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Disparities in gallbladder, intra-hepatic bile duct, and other biliary cancers among multi-ethnic populations: a California Cancer Registry study

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Disparities in gallbladder, intra-hepatic bile duct, and other biliary cancers among multi-ethnic populations: a California Cancer Registry study

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Content Disparities in gallbladder, intra-hepatic bile duct, and other biliary cancers among multi-
ethnic populations: a California Cancer Registry study
by
Qiyu Yang
A Thesis Presented to the
FACULTY OF THE USC KECK SCHOOL OF MEDICINE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF SCIENCE
(MOLECULAR EPIDEMIOLOGY)
December 2021
Copyright 2021 Qiyu Yang

ii
Table of Contents
List of Tables ................................................................................................................ iii
List of Figures .............................................................................................................. iv
Abbreviations ................................................................................................................ v
Abstract ........................................................................................................................ vi
Introduction ................................................................................................................... 1
Methods ........................................................................................................................ 8
Data Source .............................................................................................................. 8
Data Variables .......................................................................................................... 9
Statistical Analysis .................................................................................................. 10
Results ........................................................................................................................ 11
Sociodemographic characteristics of GBC cases in California ............................... 11
Clinical characteristics of GBC cases in California ................................................. 12
Determinants of receipt of treatment ....................................................................... 13
Survival analysis ..................................................................................................... 14
Discussion .................................................................................................................. 27
References ................................................................................................................. 31

iii
List of Tables

Table 1. Sociodemographic characteristics of NHW, NHB, USB Hispanics, FB Hispanic,
USB Asian, and FB Asian GBC patients in California (1990-2020)
………………………………………………………………………………………………..….16

Table 2. Clinical characteristics of NHW, NHB, USB Hispanic, FB Hispanic, USB Asian,
and FB Asian GBC patients in California (1990-2020)
………………………………………………………………………………………………..….19

Table 3. Determinants of receipt of treatment among NHW, NHB, USB Hispanic, FB
Hispanic, USB Asian, and FB Asian GBC patients in California (1990-2017)
………………………………………………………………………………………………..….21

Table 4. Multivariate GBC-specific survival analyses for GBC cases in California (199-
2020)
………………………………………………………………………………………………..….23

Table 5. Survival analyses of GBC patients stratified by cancer stage based on Stage
SEER
………………………………………………………………………………………………..….25

iv
List of Figures

Figure 1. Estimate Age-Standardized incidence rate (world) in 2020
………………………………………………………………………………………………..…...4

Figure 2. Age-Standardized Mortality rate in North America, 2020
………………………………………………………………………………………………..…...5

Figure 3. Age-Standardized incidence and Mortality rate, North America, 2020
………………………………………………………………………………………………..…...6

Figure 4. Hispanic Population Percentage in the US by States
………………………………………………………………………………………………..…...7

v
Abbreviations

CCR California Cancer Registry
CI Confidence Interval
HR Hazard ratio
ICD-9 International Classification of Diseases, 9
th
Revision
ICD-10 International Classification of Diseases, 10
th
Revision
ICD-O-3 International Classification of Diseases for Oncology, 3
rd

Revision
LR test Likelihood ratio test
NAACCR North American Association of Central Cancer Registries
NCI National Cancer Institute
NHB Non-Hispanic Black
NHW Non-Hispanic White
FB Foreign born
USB U.S. born
OR Odds ratio
SEER Surveillance, Epidemiology, and End Results Program
SES Socioeconomic status
N0 No lymph nodes involvement
N1 Lymph nodes involvement
M0 No metastasis
M1 Metastasis

vi
Abstract

Background

The incidence of gallbladder, intra-hepatic bile duct, and biliary cancers (we
collectively refer to them as GBC henceforth) is low, but due to vague symptoms and lack
of proper screening technologies, the mortality rate is high. The determinants of GBC are
not clear, although there are some putative risk factors. There are very few population-
based studies of GBC, especially focused on the Hispanic population, where the
incidence is high.

Methods
Using California Cancer Registry Data (CCR) from 1990-2018 we evaluated
demographic and clinical characteristics of patients, such as stage, treatment status, and
survival rate, and compared across racial/ethnic groups defined by nativity, which
included: non-Hispanic whites (NHW), non-Hispanic Blacks (NHB), US born Hispanics,
foreign-born Hispanics, US born Asians, and foreign-born Asians. Descriptive statistics,
logistic regression, and Cox regression were used.

Results
We included 37,393 patients’ records in the study. Statistically significant
differences in frequencies were observed for all sociodemographic characteristics across
racial/ethnic groups defined by nativity. Specifically, when considering age, NHB (50%),
USB Hispanic (49.2%) and FB Hispanic (56.0%) patients had almost doubled proportion
of diagnosis younger than 69 years old than NHW (35.7%). More than half of these

vii
population fall into low socioeconomic status (SES) category and FB Hispanic patients
had the largest proportion of individuals without insurance (6.4%), which was 6 times
compared to NHW (0.9%). Compared to NHW (10.6%), NHB (11.4%), USB Hispanic
(8.8%), USB Asian (8.7%) and FB Asian (10.8%) patients, there were more FB Hispanic
patients (12.9%) with remote metastasis at the time of diagnosis (p<0,001). FB Hispanic
patients also had the greatest proportion of diagnoses with regional organ involvement
and tumor size over 5 centimeters. In addition, FB Hispanic patients (1.64%) had the
largest proportion of not receiving treatment compared to NHW (0.9%) and NHB (0.7%)
patients (p<0.001). Patients who had older age and had middle SES, had higher likelihood
of receiving treatment. Among all GBC cases in this study, NHB, USB Hispanics, and FB
Hispanics did not statistically significantly differ from NHW in their risk of dying of GBC
and related cancers. In contrast, US born and foreign-born Asian patients had lower risk
of dying of GGBC and related cancers than NHW patients. With increasing in age, the
chance of dying from GBC increases. Survival chances were inversely correlated with
advance in cancer stage.

Conclusion
Between 1990-2018, disparities in GBC and related cancers across
racial/ethnic groups in California were observed in our study. FB Hispanic patients had
greater proportion of individuals diagnosed with GBC when younger than 69 years old,
greater proportion of individuals with low SES, greater proportion of diagnoses with
remote extension of the tumor, and were less likely to receive treatment. Despite these
differences, neither of these groups showed disparities in survival compared to NHW

viii
cases. Instead, we observed that Asian patients were less likely to die of GBC and related
cancers compared to NHW cases. The observed large percent of Hispanic patients with
unemployment, low SES, and uninsured status, which can all act as barriers for accessing
diagnosis and treatment, may explain the greater proportion of diagnosis at more
advanced stage and grade in this population.

Key words: Gallbladder cancer, Hispanics, population-based, California Cancer Registry

1
Introduction

The gallbladder (GB), as part of our digestive system, is in the upper abdomen
area under the liver. The gallbladder store bile produced by the liver, and releases bile
into the small intestine through the bile duct to help digest fats
1
. There are several
common GB conditions, such as cholelithiasis, cholecystitis, gallstone pancreatitis, and
congenital biliary cysts. Some conditions can be treated with antibiotics; and sometimes,
patients can take oral medication like Ursodeoxycholic acid to help dissolve small
gallstones and reduce symptoms
2
. Treatment like cholecystectomy can be performed to
patients under certain conditions and there are no observable problems with major
health
3
.
Gallbladder cancer, other bile duct cancers, and intra-hepatic bile duct cancers
(collectively referred to here as GBC) are rare GB conditions and are considered as one
of the most aggressive cancers of the biliary tract. These tumors arise from the epithelial
lining of the GB and the cystic duct, with over 90 percent of GBC being adenocarcinomas,
while others are squamous cell carcinoma
4
. GBC only accounts for 1.2% of all global
cancer diagnosis
5
, with fewer than 20,000 cases per year in the United States
6
.
Surprisingly, it ranks as the 17
th
most common cause of death from cancer and the most
common cancer in 20
th
century
7
. The age-standardized incidence rate (ASR) of GBC is
higher in certain countries, as shown in the darkest blue color countries shown in Figure
1, such as Bolivia, where the ASR is 8.5 per 100,000, and 5.6 per 100,000 and 2.9 per
100,000 in Chile and Republic of Korea, respectively
4
.
The estimate number of new cases of GBC in 2020 was 115,949 globally while the
total number of deaths is 84,695 worldwide in the same year
4
. The GLOBOCAN data

2
indicates that there were 2301 deaths in United States in 2020 (ASR = 0.31 per 100,000,
Figure 2). Lacking sensitive screening tests leads to only 1 in 5 diagnoses being made in
an early stage. About 43% of GBC cases were diagnosed after spread to lymph nodes,
or regional organs. Nearly half of diagnoses are made after distant metastasis
8
. Without
early detection, the 5-year survival rate decreases dramatically from 80% at stage 0 to
28% at stage II
9
, the median survival of advanced stage cancer is approximately one
year
5
. Notably, the incidence of GBC is always higher in female than males, regardless
of racial and ethnic groups worldwide. Male GBC age-standardized incidence rate is 0.51
per 100,000, whereas among females it is 0.82 per 100,000 in North America (Figure 3).
The overall survival of GBC in the United States has been improved in recent years
with enhanced healthcare system and advances in the combination of diagnostic
modalities such as ultrasound (US) evaluation combined with computerized tomography,
magnetic resonance imaging or positron emission tomography, which can provide a more
accurate structural and functional assessment
10
. However, according to American
Cancer Society, GBC incidence rates in both Hispanic men and women are doubled those
in non-Hispanic White population from 2014 to 2019
11
, also they were less likely to receive
curative surgeries, hence the overall survival of GBC for Hispanic population did not show
improvements in the past decades
12
. Although the incidence of all cancers in Hispanics
is lower than non-Hispanic populations, especially in lung cancer and breast cancer
13
,
the incidence and mortality of GBC in Hispanics stood out.
The main causes of GBC are still not clear, but several predisposition factors are
correlated with GBC, like cholelithiasis, which was also called gallstones; porcelain
gallbladder, one of the GB conditions that the wall of gallbladder covered with calcium

3
deposites, and also pre-cancerous changes of choledochal cysts
14
. In addition, some
other disruptions of health may cause genetic mutations such as reproductive factors,
chronic infections, and carcinogens exposures
15
. Such aberrations can accumulate
during a person’s lifetime, which may have consequences in older ages. According to the
American Institute for Cancer Research (AICR), Body Mass Index (BMI) was also
statistically significant related to GBC, with 5kg/m
2
increases in weight, the risk of having
GBC increased by 25%
7
.
Despite the total GBC cases each year in the United States is decreasing, there
is no clear understanding for the high incidence and mortality in Hispanics. In this study,
we use data of cancer patterns in California, to evaluate demographic, clinical variables,
and survival rates, across racial and ethnic groups, with large representation of Hispanics.
According to the US Census Bureau of 2019, Hispanic groups ranked as the second
largest population in the United States, whereas non-Hispanic white ranked as number
one population. The majority of the Hispanic population resides in the southwestern area
in the US (Figure 4). The top two states that have the largest Hispanic population are
California and Texas, consists of 32.4% and 32% of total Hispanics, respectively
16
. In
California, over 80% of Hispanics originally came from Mexico, roughly about 10% are
Central Americans, and the rest of the Hispanic population includes South Americans,
Puerto Ricans, Cuban, and other Hispanic origin
17
.

4
Figure 1. Estimate Age-Standardized incidence rate (world) in 2020

Darker blue areas indicate higher ASR, located in most part of south-east Asia area, part of
Africa and south America (data source: GLOBOCAN 2020 Graph production: IARC
(http://gco.iarc.fr/today World Health Organization)

5

Figure 2. Age-Standardized Mortality rate in North America, 2020

Based on population, the ASR is 0.31. Data source: GLOBOCAN 2020 Graph
production: IARC (http://gco.iarc.fr/today) World Health Organization.

6
Figure 3. Age-Standardized incidence and Mortality rate, North America, 2020

Black circled box indicates incidence rate in the United State between male
and female, where shows the odd ratio between female ASR and male ASR is
1.6. Data source: GLOBOCAN 2020 Graph production: IARC
(http://gco.iarc.fr/today) World Health Organization.

7

Figure 4. Hispanic Population Percentage in the US by States

According to the U.S. Census bureau, Population Estimates Program(PEP), the
majority of Hispanics and Latinos reside in southwestern states of the United States,
top five states are California, Nevada, Arizona, New Mexico, and Texas (3).

8
Methods
Data Source
Data were obtained from the California Cancer Registry (CCR), a
comprehensive statewide cancer surveillance program. All patients’ personal information
were deleted to protect their privacy. The inclusion criteria were adult patients between
1990 and 2018. Primary GB cases were identified by National Cancer Institute
Surveillance, Epidemiology, and End Results Program (NIH SEER) site codes (21080,
Gallbladder; 21090, other biliary cancers; 21072, intra hepatic bile duct), and both
localized and invasive cancer cases were included in this study. Hispanic subpopulations
were defined by the NAACCR Hispanic Identification Algorithm (NHIA), which is a registry
algorithm that identifies all Hispanic patients and can be used to determine country of
origin. NHIA is derived from a combination of NAACCR variables to classify cases as
Hispanics or non-Hispanics based on Spanish/Hispanic origin, last name, maiden name,
birthplace, race, sex, and the Indian Health Services (IHS) linkage. We assigned nativity
as USB and FB based on birthplace information. For individuals with missing birthplace
(9.9%), we used an algorithm previously reported
18
. Briefly, individuals with age at SSN
issue of 25 or younger were considered USB, whereas those with age at SSN issue over
25 were considered FB. Individuals who did not have information on either birthplace or
SSN issued age were considered as missing values. We combined nativity, race group
variable, and Hispanic subpopulations to create the following mutually exclusive groups:
NLW, NLB, U.S. born Hispanics (USB Hispanics), foreign-born Hispanics (FB Hispanics),
US born Asians and foreign-born Asians. Survival status (alive, deceased due to CRC,

9
deceased due to other causes) were identified based on the International Classification
of Diseases, 9
th
Revision and 10
th
Revision (ICD-9 and ICD-10).

Data Variables
In addition to nativity as mentioned before, we also included the following
variables from CCR database: ages at diagnosis based on mean age at diagnosis (<69,
69-79, >79), ages at diagnosis based on tertile distribution (,60, 60-70, >70), sex of
patients, socioeconomic status (SES) (low, middle, high), insurance status (not insured,
managed care, Medicaid, Medicare, other and unknown), religion status (Roman catholic,
none, agnostic or atheist, Christian not catholic, Jewish, other western, eastern and
unknown), occupations (agriculture, forestry, fishing, construction, manufacturing, mining,
transportation, communication, public administration, wholesale, retail, professional,
entertainment, recreation, active military, business, repair, personal services, not working
and unknown), SSN issued status (no SSN and with SSN at the time of diagnosis). We
also considered the following clinical characteristics: histological grade (Grade-I well
differentiated, II-moderately well differentiated, III-poorly differentiated, IV-
undifferentiated/anaplastic, not stated and unknown), cancer stage based on Stage
SEER (in situ, localized, regional, remote and unstaged/unknown), tumor size (no tumor,
<2cm, 2-5cm, >5cm and unknown), type of records indicate the accuracy of our data
(healthcare facilities, autopsy, death certificates), lymph node involvement at the time of
diagnosis (N0 and N1), presence of metastasis (M0 and M1). Specifically, N0 and N1 for
lymph nodes indicate negative and positive lymph nodes involvement, and M0 and M1 in
presence of metastasis refer to no metastasis and metastasis
19
. Finally, we created a

10
composite overall treatment status variable (no treatment vs. had treatment) based on
record of the following treatments: surgery, chemotherapy, radiotherapy, hormones
therapy, immunotherapy.

Statistical Analysis
All the sociodemographic and clinical characteristics across racial/ethnic
groups were represented by proportion. P-value was used to test differences across
groups for both sociodemographic and clinical variables. Odds ratios (OR) and 95%
confidence intervals (CI) from multivariable logistic regression models were used to
assess possible determinants of treatment receiving status. Hazard ratio (HR) and
associated 95% confidence intervals (CIs) from multivariable Cox proportional hazards
regression model was used to evaluate survival disparities between NHB, USB Hispanics,
FB Hispanics, USB Asians, FB Asians relative to NHW. Variables like age at diagnosis,
sex, SES, insurance status, histological grade, cancer stage, treatment status were
included in multivariable model. Statistical analyses were performed with Stata/SE 15.1
for MacOS (StataCorp, College Station, TX, USA).

11
Results
Sociodemographic characteristics of GBC cases in California
A total of 37,393 GBC cases were diagnosed in California among NHW (19,208),
NHB (1,974), USB Hispanics (5,482), FB Hispanics (4,778), USB Asians (2,236), and FB
Asians (3,715) between 1990-2018. Based on the mean age of diagnosis, patients
younger than 69 consists of 42.3% of the total case population, where those over 79 years
old were 26% of cases (n = 9708). When considering a younger cutpoint based on tertiles,
we observed that the majority of cases over 70 years old (n = 19468), with 21% being
younger than 60 years old. Over half of the patients were female (52.5%, n = 20563). The
two groups that had the most cases for the religion categories were catholic and unknown.
Over 50% of patient were jobless at the time of diagnosis.
Statistically significant differences in frequencies were observed for all these
variables across racial/ethnic groups defined by nativity (Table 1). Compared to NHW,
NHB and Hispanic groups had almost double the proportion of diagnosis younger than
69 years old (35.7% NHW vs. 50% NHB, 49.2% USB Hispanics, 56.0% FB Hispanics).
More than half of NHB (56.8%), USB Hispanics (61.1%), FB Hispanics (67.2%) fall into
low-income SES, whereas the majority of NHW patients (51.4%), USB Asians (50.4%),
and FB Asians (43.8%) were of high SES (p<0.001). Compared to NHW, NHB, USB
Hispanics, USB Asians and FB Asians, FB Hispanics had doubled the proportion of
female patients (FB Hispanics female 64.2% vs FB Hispanics male 35.8%), while other
racial/ethnic groups had almost equal distribution for both sexes. Additionally, FB
Hispanics had the highest proportion of individuals without insurance (6.4%), which was

12
6 times compared to NHW (0.9%). Most patients had managed care, Medicaid, or
Medicare.

Clinical characteristics of GBC cases in California
Clinical characteristics were evaluated across racial/ethnic groups defined by
nativity (Table 2). A total of 37,393 GBC cases were diagnosed in California among NHW
(19,208), NHB (1,974), USB Hispanic (5,482), FB Hispanic (4,778), USB Asian (2,236),
and FB Asian (3,715) individuals between 1990-2018. Most patients were diagnosed as
Grade II-moderately well-differentiated and Grade III-poorly differentiated (23.2%, n =
8226 and 20.3%, n = 7170, respectively); also, most patients were diagnosed when tumor
spread to regional organ (14%, n =5156) or tumor already metastasized (11%, n = 3956).
For the majority of cases, the tumor size was between 2 to 5 centimeters, without lymph
nodes involvement and no metastasis at the time of diagnosis. Most of the cases were
recorded in healthcare facilities, with very few done at autopsy or through death
certificates (<2%).
Statistically significant differences in frequencies were observed for all variables
across race/ethnicity defined by nativity (p-value < 0.001) except lymph nodes
involvement (Table 2). About 12-15% of cases had involvement of lymph nodes across
all racial/ethnic groups. FB Hispanics showed a slightly higher proportion of grade-II
differentiation level than all other racial/ethnic group categories (25.2% in FB Hispanics
vs. 22.4% in NHW, 21.3% in NHB, 23.9% in USB Hispanics, 23.9% in USB Asians, and
24.9% in FB Asians, p-value < 0.001), also compared to NHW, NHB, USB Asians, FB
Asians, USB and FB Hispanics had slightly higher proportion of grade-III poorly

13
differentiation level (USB Hispanics 22.2%, FB Hispanics 23.5% vs. NHW 19.1%, NHB
20.7%, USB Asians 17.1%, FB Asians 21.0%). More FB Hispanics (12.9%) were
diagnosed with remote metastasis than NHW (10.6%), NHB (11.4%), USB Hispanics
(8.8%), USB Asians (8.7%), and FB Asians (10.8%) (p<0.001). Similarly, FB Hispanics
had the greatest proportion of diagnoses with regional organ involvement (15.1%,
p<0.001) (Table 2). At the time of diagnoses, NHB (26.8%) and FB Hispanics (26.4%)
had the greatest proportion of tumors with size over 5 centimeters compared to NHW
(23.6%), USB Hispanics (25.5%), USB Asians (22.4%), and FB Asians (25.2%) (p <
0.001). More NHB (26.3%) were diagnosed with metastasis than NHW (20.9%), USB
Hispanics (24.4%), FB Hispanics (21.8%), USB Asians (20.6%), and FB Asians (18.4%)
had the smallest proportion of metastasis at the time of diagnoses (p < 0.001).
Overall, for treatment status, over 98% of GBC cases had treatment. However, FB
Hispanics (1.64%) had the largest proportion of not receiving treatment compared NHW
(0.9%), NHB (0.7%), USB Hispanics (1.1%), USB Asians (1.3%) and FB Asians (1.44%)
(p-value < 0.001) (Table 2).

Determinants of receipt of treatment
Treatment receiving status were evaluated by sociodemographic and clinical
determinants using multivariable models (Table 3). Most patients choose treatment (98%,
n = 35840).
Compared to NHW cases, FB Hispanics cases were significant less likely to
receive treatment (OR = 0.68, 95% CI: 0.53-0.86) whereas NHB (OR = 1.45, 95% CI:
0.88-2.38) and USB Hispanic cases (OR = 1.09, 95% CI: 0.82-1.43) were more likely to

14
receive treatment, even though the latter two estimates were not statistically significant.
Asian cases had slightly lower chance to receive treatment compared to NHW cases
(table 3).
Overall, patients who had older age, and had higher likelihood of receiving
treatment. Similarly, patients of middle SES (OR = 1.11, 95% CI: 0.86-1.43) were more
likely to receive treatment compared to those of low SES, whereas those of high SES
(OR = 0.99, 95% CI: 0.80-1.22) showed almost no difference compared to low SES
patients.
Grade-IV cases were more likely to receive treatment (OR = 1.52, 95% CI: 0.69-
3.33) compared to Grade-I tumor, although the estimate was not statistically significant.
Inversely, cases with localized stage (OR = 0.33, 95% CI:0.25-0.44), extension to regional
organs (OR = 0.23, 95% CI: 0.19-0.28), and extension to remote organs (OR = 0.97, 95%
CI: 0.67-1.39) at the time of diagnosis had lower likelihood of receiving treatment
compared to tumors diagnosed with in situ stage. Similar results were observed in tumor
size at the time of diagnosis where the likelihood of receiving treatment decrease with
increasing tumor size, albeit none of the estimates were statistically significance (Table
3).

Survival analysis

Survival analyses using multivariate analyses (Table 4) showed that among GBC
cases, NHB, USB Hispanic, and FB Hispanic patients did not statistically significantly
differ from NHW patients in their risk of dying of GBC. However, compared to NHW
patients USB Asians (HR = 0.83, 95% CI = 0.71-0.97, Wald p-value = 0.02) and FB Asians

15
(HR = 0.82, 95% CI = 0.71-0.91, Wald p-value = 0.001) were less likely to die. Those
between 69 and 79 years old were ~35% more likely to die of GBC than NHW (HR = 1.38,
95% CI = 1.27-1.50, Wald p-value < 0.001), also age over 79 were ~86% more likely to
die of GBC (HR = 1.86, 95% CI = 1.70-2.03 Wald p-value < 0.001) (Table 5). Compare to
GBC cases who were in low SES, survival rate increase with increase of income, middle
SES (HR = 0.97, 95% CI = 0.89-1.06, Wald p-value < 0.58) and high SES (HR = 0.81,
95% CI = 0.75-0.88, Wald p-value < 0.001) were less likely to die from GBC.
For clinical variables, survival rates were inversely correlated with advance in
cancer stage. Localized tumor (HR = 5.01, 95% CI = 2.56-9.82, Wald p-value < 0.001),
metastasize to regional organ (HR = 7.06, 95% CI = 3.64-13.71, Wald p-value < 0.001),
metastasize to remote organ (HR = 16.01, 95% CI = 8.29-30.94, Wald p-value < 0.001)
were dramatically more likely to die of GBC compared to tumor in situ stage.
Results did not different when we evaluated survival stratifying by stage (Table 5).

16

Table 1. Sociodemographic characteristics of NHW, NHB, USB Hispanics, FB Hispanic, USB Asian, and FB Asian GBC
patients in California (1990-2020)

NHW NHB
USB
Hispanic
FB Hispanic US Asian FB Asian
p-value

19208 1974 5482 4778 2236 3715

AGE of diagnosis

<0.001
<69 6864(35.7%) 987(50.0%) 2695(49.2%) 2675(56.0%) 872(39.0%) 1722(46.4%)

>=69 and <=79 6391(33.3%) 595(30.1%) 1652(30.1%) 1313(27.5%) 739(33.1%) 1180(31.8%)

>79 5953(31.0%) 392(19.9%) 1135(20.7%) 790(16.51%) 625(28.0%) 813(21.9%)

AGE of diagnosis

<0.001
<60 3187(16.6%) 497(25.2%) 1439(26.2%) 1528(32.0%) 437(19.5%) 848(22.8%)

>=60 and <=70 4719(24.6%) 612(31.0%) 1555(28.9%) 1410(29.5%) 563(25.2%) 1100(29.6%)

>70 11302(58.5%) 865(43.8%) 2458(44.8%) 1840(38.5%) 1236(55.3%) 1767(47.6%)

Sex of the patient

<0.001
Male 9145(47.6%) 861(43.6%) 2278(41.6%) 1710(35.8%) 1058(47.3%) 1776(47.8%)

Female 10062(52.4%) 1112(56.3%) 3204(55.4%) 3068(64.2%) 1178(52.7%) 1939(52.2%)

SES

<0.001
Low SES 5138(26.7%) 1121(56.8%) 3347(61.1%) 3213(67.2%) 671(30.0%) 1359(36.6%)

Middle SES 4201(21.9%) 380(19.3%) 974(17.8%) 800(16.7%) 439(19.6%) 727(19.6%)

High SES 9869(51.4%) 473(24.0%) 1161(21.2%) 765(16.0%) 1126(50.4%) 1629(43.8%)

Insurance Status

<0.001
Not Insured 180(0.9%) 48(2.4%) 133(2.4%) 306(6.4%) 28(1.3%) 126(3.4%)

Managed Care 6469(33.7%) 676(34.2%) 1781(32.5%) 1037(21.7%) 840(37.6%) 992(26.7%)

Medicaid 678(3.5%) 213(10.8%) 760(13.9%) 1080(22.6%) 169(7.6%) 518(13.9%)

17
Medicare 7805(40.6%) 675(34.2%) 2013(36.7%) 1387(29.0%) 948(42.4%) 1483(39 9%)

Other 514(2.7%) 87(4.4%) 134(2.4%) 123(2.6%) 54(2.4%) 80(2.2%)

Unknown 3562(18.5%) 275(13.9%) 661(12.1%) 845(17.7%) 197(8.8%) 516(13.9%)

Religion Status

<0.001
Roman Catholic 3478 (18.1%) 143 (7.2%) 3027 (55.2%) 3275 (68.5%) 360 (16.1%) 795 (21.4%)

None, agnostic or atheist 1220 (6.4%) 76 (3.9%) 139 (2 .5%) 94 (2 .0%) 173 (7.7%) 253 (6.8%)

Christian not catholic 6586 (34.3%)
1058
(53.6%)
807 (14.7%) 551 (11.5%) 372 (16.6%) 693 (18.7%)

Jewish 736 (3.8%) 2 (0.1%) 8 (0.1%) 16 (0.3%) 0 (0.0%) 1 (<1%)

other western 15 (0.1%) 4 (0.2%) 2 (<1%) 1 (<1%) 0 (0.0%) 2 (0.1%)

eastern 131 (0.7%) 23 (1.2%) 5 (0.1%) 3 (0.1%) 325 (14.5%) 627 (16.9%)

unknown 7042(36.7%) 668 (33.8%) 1494 (27.3%) 838 (17.5%)
1006
(45.0%)
1344 (36.2%)

industry

<0.001
Agriculture, Forestry,
Fishing
115 (0.6%) 5 (0.3%) 89 (1.6%) 166 (3.5%) 17 (0.8%) 49 (1.3%)

construction 413 (2.2%) 26 (1.3%) 130 (2.4%) 100 (2 .1%) 15 (0.7%) 34 (0.9%)

manufacturing 356 (1.9%) 21 (1.1%) 82 (1.5%) 71 (1.5%) 25 (1.1%) 57 (1.5%)

mining 12 (0.1%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (<1%)

transportation,
communication, public
admin
501 (2 .6%) 68 (3.4%) 101 (1.8%) 38 (0.8%) 38 (1.7%) 45 (1.2%)

wholesale 25 (0.1%) 0 (0.0%) 5 (0.1%) 2 (<1%) 1 (<1%) 4 (0.1%)

retail 357 (1.9%) 29 (1.5%) 70 (1.3%) 78 (1.6%) 48 (2.1%) 77 (2.1%)

profession1l, entertainment,
recreation
1559 (8.1%) 128 (6.5%) 167 (3.0%) 105 (2.2%) 121 (5.4%) 180 (4.8%)

active military 76 (0.4%) 7 (0.4%) 6 (0.1%) 3 (0.1%) 8 (0.4%) 9 (0.2%)

18
business, repair, personal
services
275 (1.4%) 44 (2 .2%) 84 (1.5%) 116 (2 .4%) 23 (1.0%) 79 (2.1%)

not working
11245
(58.5%)
1173
(59.4%)
3801 (69.3%) 3376 (70.7%)
1595
(71.3%)
2471 (66.5%)

unknown 4274 (22 .3%) 473 (24.0%) 947 (17.3%) 723 (15.1%) 345 (15.4%) 709 (19.1%)

19
Table 2. Clinical characteristics of NHW, NHB, USB Hispanic, FB Hispanic, USB Asian, and FB Asian GBC patients in
California (1990-2020)

NHW NHB USB Hispanic FB Hispanic US Asian FB Asian
p-value

19208 1974 5482 4778 2236 3715
Histological grade

<0.001
Grade-well diff 1499 (8.2%) 163 (8.7%) 448 (8.8%) 375 (8.3%) 187 (9.2%) 302 (8.6%)

II-moderately well diff 4106 (22.4%) 401 (21.3%) 1220 (23.9%) 1135 (25.2%) 488 (23.9%) 876 (24.9%)

III-poorly diff 3507 (19.1%) 389 (20.7%) 1130 (22.2%) 1055 (23.5%) 348 (17.1%) 741 (21.0%)

IV-undiff/anaplastic 208 (1.1%) 19 (1.0%) 72 (1.4%) 50 (1.1%) 25 (1.2%) 50 (1.4%)
Not Stated 9016 (49.2%) 911 (48.4%) 2231 (43.7%) 1883 (41.9%) 992 (48.6%)
1555
(44.1%)

Missing 872 (4.5%) 91 (4.6%) 381 (7.0%) 280 (5.9%) 196 (8.8%) 191 (5.1%)
Stage Summary on Stage
SEER

<0.001
In situ 285 (1.5%) 23 (1.2%) 119 (2.2%) 95 (2.0%) 35 (1.6%) 52 (1.4%)

localized 1744 (9.1%) 134 (6.8%) 370 (6.7%) 372 (7.8%) 154 (6.9%) 355 (9.6%)

regional
2807
(14.6%)
236 (12.0%) 594 (10.8%) 721 (15.1%) 256 (11.4%) 542 (14.6%)

Remote 2037 (10.6%) 225 (11.4%) 482 (8.8%) 615 (12.9%) 194 (8.7%) 403 (10.8%)
unstaged/unknown
12335
(64.2%)
1356
(68.7%)
3917 (71.5%) 2975 (62.3%)
1597
(71.4%)
2363
(63.6%)

Tumor size

<0.001
No tumor 96 (1.1%) 8 (0.9%) 28 (1.1%) 10 (0.4%) 11 (0.9%) 7 (0.4%)

<2 cm 2038 (24.0%) 179 (19.0%) 593 (23.0%) 483 (21.5%) 283 (23.8%) 417 (22.0%)

2-5 cm 4350 (51.2%) 501 (53.3%) 1303 (50.5%) 1164 (51.7%) 628 (52.9%) 991 (52.4%)
>5 cm 2006 (23.6%) 252 (26.8%) 657 (25.5%) 593 (26.4%) 266 (22.4%) 477 (25.2%)

20
Missing
10718
(55.8%)
1034
(52.4%)
2901 (52.9%) 2528 (52.9%)
1048
(46.9%)
1823
(49.1%)

Lymph node involvement

0.14
No lymph nodes involvement 4649 (85.1%) 533 (85.0%) 1572 (87.6%) 1248 (84.6%) 670 (85.6%)
1002
(84.9%)

lymph nodes involvement 814 (14.9%) 94 (15.0%) 223 (12.4%) 228 (15.4%) 113 (14.4%) 178 (15.1%)

Missing
13745
(71.6%)
1347
(68.2%)
3687 (67.3%) 3302 (69.1%)
1453
(65.0%)
2535
(68.2%)

Metastasis

<0.001
M0 3424 (79.1%) 381 (73.7%) 1200 (75.6%) 977 (78.2%) 524 (79.4%) 781 (81.6%)

M1 906 (20.9%) 136 (26.3%) 387 (24.4%) 273 (21.8%) 136 (20.6%) 176 (18.4%)

Missing
14878
(77.5%)
1457
(73.8%)
3895 (71.1%) 3528 (73.8%)
1576
(70.5%)
2758
(74.2%)

Type of records

<0.001
Healthcare facility
18891
(98.3%)
1935
(98.0%)
5433 (99.1%) 4717 (98.7%)
2218
(99.2%)
3669
(98.8%)

Autopsy 59 (0.3%) 12 (0.6%) 9 (0.2%) 13 (0.3%) 6 (0.3%) 4 (0.1%)

Death certificate 258 (1.3%) 27 (1.4%) 40 (0.7%) 48 (1.0%) 12 (0.5%) 42 (1.1%)

Treatment Status

<0.001
No treatment 181(0.9%) 15 (0.7%) 56 (1.1%) 76(1.64%) 28(1.30%) 52 (1.44%)

Had treatment 18431 (99%) 1910(99%) 5272(98.9%) 4546(98.3%) 2142(98.7%) 3539(98.5%)

21
Table 3. Determinants of receipt of treatment among NHW, NHB, USB Hispanic, FB Hispanic, USB Asian, and FB
Asian GBC patients in California (1990-2017)

No Treatment
Treatment
received

N = 494 N = 35840 Odds Ratio Lower CI Upper CI p-value
Population

0.004
NHW
238 (48.2%) 18431 (51.4%)
1
ref

NHB 17 (3.4%) 1910 (5.3%) 1.45 0.88 2.38 0.14
USB Hispanics
63 (12.8%) 5272 (14.7%) 1.09 0.82 1.43 0.59
FB Hispanics
87 (17.6%) 4546 (12.7%) 0.68 0.53 0.86 0.002
USB Asians 29 (5.9%) 2142 (6.0%) 0.95 0.65 1.41 0.81
FB Asians
60 (12.1%) 3539 (9.9%) 0.76 0.57 1.01 0.06
Age at diagnosis

<0.001
< 69
250 (50.6%) 15260 (42.6%)
1
ref

69-79 156 (31.6%) 11401 (31.8%) 1.52 0.93 2.49 0.098
> 79
88 (17.8%) 9179 (25.6%) 1.42 1.14 1.78
0.002
SES

0.56
Low SES
204 (41.3%) 14226 (39.7%)
1
ref

Middle SES 90 (18.2%) 7188 (20.1%) 1.11 0.86 1.43 0.432
High SES
200 (40.5%) 14426 (40.3%) 0.99 0.80 1.22
0.92
Insurance Status

<0.001
Not Insured
7 (1.4%) 807 (2.3%)
1
ref

Managed Care 138 (27.9%) 11496 (32.1%) 0.62 0.29 1.35 0.23
Medicaid
46 (9.3%) 3289 (9.2%) 0.60 0.27 1.34
0.22
Medicare
175 (35.4%) 13845 (38.6%) 0.60 0.28 1.29
0.19
Other 17 (3.4%) 967 (2.7%) 0.43 0.18 1.04 0.062
Unknown
111 (22.5%) 5436 (15.2%) 0.38 0.17 2.0.82
0.013
Histological grade

<0.001

22
Grade I -well diff 74 (15.0%) 2886 (8.4%) 1ref
II-moderately
194 (39.3%) 7988 (23.3%) 1.06 0.81 1.39
0.65
III-poorly diff
153 (31.0%) 6993 (20.4%) 1.18 0.89 1.56
0.25
IV-undiff/anaplastic 7 (1.4%) 415 (1.2%) 1.52 0.69 3.33 0.29
Not Stated
66 (13.4%) 16044 (46.7%) 6.20 4.44 8.66
0.000
Cancer stage in SEER

<0.001
in situ 0 (0.0%) 608 (1.7%) 1ref
localized
77 (15.6%) 3026 (8.4%) 0.33 0.25 0.44
0.000
regional
182 (36.8%) 4938 (13.8%) 0.23 0.19 0.28
0.000
remote 35 (7.1%) 3913 (10.9%) 0.97 0.67 1.39 0.87
unstaged/unknown
200 (40.5%) 23355 (65.2%) omitted omitted omitted omitted
Tumor size

<0.001
No tumor
1 (0.3%) 159 (1.0%) 1ref

<2 cm 90 (29.9%) 3784 (22.8%) 0.27 0.03 2.00 0.20
2-5 cm 164 (54.5%) 8542 (51.4%) 0.34 0.04 2.48 0.29
>5 cm
46 (15.3%) 4136 (24.9%) 0.59 0.08 4.37
0.61
Lymph nodes involvement

0.007
N0 110 (77.5%) 9547 (85.5%) 1ref
N1
32 (22.5%) 1613 (14.5%) 0.58 0.39 0.87
0.008
Metastasis

0.002
M0 74 (92.5%) 7199 (78.2%) 1ref
M1
6 (7.5%) 2003 (21.8%) 3.402 1.47 7.83
0.004

23

Table 4. Multivariate GBC-specific survival analyses for GBC cases in California (199-2020)
Hazard Ratio Lower CI Upper CI p-value

Population

<0.0001
NHW 1
ref

NHB 1.06 .91 1.24 0.40
USB Hispanics 1.07 0.96 1.19 0.21
FB Hispanics .96 0.85 1.09 0.56
US Asians 0.85 0.73 1.00 0.05
FB Asians 0.82 0.71 0.93 0.003
Age at diagnosis

<0.0001
< 69 1
ref

69-79 1.35 1.29 1.42 <0.001
Sex 0.1
Male 1
ref

Female 0.98 0.92 1.05 0.65
SES

<0.001
Low SES 1
ref

<0.0001
Middle SES 0.97 0.89 1.07 0.58
High SES 0.81 0.75 0.88 <0.001
Insurance Status

0.012
Not Insured 1
ref

Managed Care 0.69 0.55 0.87 0.002
Medicaid 0.97 0.76 1.23 0.81
Medicare 0.72 0.57 0.91 0.006
Other 0.79 0.59 1.07 0.14
Unknown 0.48 0.73 1.16 0.48

24

Histological grades

<0.0001
Grade I -well diff 1
ref

II-moderately well diff 1.13 0.94 1.37 0.18
III-poorly diff 1.91 1.59 2.29 <0.001
IV-undiff/anaplastic 0.69 2.03 3.78 <0.001
Not Stated 2.52 2.12 2.99 <0.001
Cancer stage based on Stage SEER

<0.0001
In situ 1
ref

Localized 5.01 2.56 9.82 <0.001
Regional 7.06 3.64 13.71 <0.001
remote 16.01 8.29 30.94 <0.001
Unstaged/unknown 8.91 4.63 17.17 <0.001
Treatment status

<0.0001
No treatment 1
ref

Had treatment 3.02 1.75 5.22 <0.001

25

Table 5. Survival analyses of GBC patients stratified by cancer stage based on Stage SEER
Hazard Ratio Lower CI Upper CI Wald p-value

Population

NHW 1
ref

NHB 1.08 0.94 1.26 0.26
USB Hispanics 1.03 0.93 1.14 0.54
FB Hispanics 0.93 0.82 1.04 0.23
US Asians 0.83 0.71 0.97 0.02
FB Asians 0.82 0.71 0.91 0.001
Age at diagnosis

< 69 1
ref

69-79 1.38 1.27 1.50 <0.001
>79 1.86 1.70 2.03 <0.001
Sex
Male 1
ref

Female 0.95 0.88 1.02 0.144
SES

<0.001
Low SES 1
ref

Middle SES 0.97 0.89 1.06 0.58
High SES 0.81 0.75 0.88 <0.001
Insurance Status

0.012
Not Insured 1
ref

Managed Care 0.74 0.59 0.93 0.01
Medicaid 1.01 0.80 1.29 0.88
Medicare 0.76 0.60 0.96 0.01
Other 0.78 0.58 1.06 0.11

26
Unknown 0.98 0.77 1.23 0.83

27
Discussion

In this study we report on disparities in GBC presentation across racial/ethnic
groups in California, taking into account nativity. We report that among FB Hispanic
patients, compared to NHW, there is a greater proportion of FB Hispanic cases diagnosed
at age younger than 69, greater proportion of females, individuals or low SES. FB
Hispanic patients also had the highest proportion of individuals without insurances. FB
Hispanic cases also showed a greater proportion of diagnoses with remote extension of
the tumor, whereas NHB cases showed the greatest proportion of larger tumors. We
report that compared to NHW cases, FB Hispanic and FB Asians cases were less likely
to receive treatment. However, both US Asians, and FB Asians had improved survival
compared to NHW cases, whereas all other groups did not differ.
Although the gallbladder is not an organ in the human body essential for survival,
adenocarcinoma of gallbladder is life threatening most of the times. Risk factors include
increasing age, female gender, obesity, chronic infections (such as salmonella typhi),
carcinogens exposures, smoking and other gallbladder conditions, such as biliary cysts,
gallstones, porcelain gallbladder, pre-cancerous changes of choledochal cysts
14
. Most
gallbladder cancers are discovered in advanced stage, where the radiotherapy is
recommended for patients sometimes, but not all patients are recommended for
radiotherapies, as it depends on lymph nodes involvement, presence of metastasis and
other clinical criteria.
The Hispanic population has been reported to have higher proportion of GBC
cases compared to non-Hispanic populations
11
. There are many potential factors that
could explain the disparities between Hispanics and non-Hispanic populations. Economic

28
status may play a role, given that incidence and death rates of GBC are higher in counties
with over 13% of households living in poverty and in counties has high percentage of
immigrants
8
. Compared to NHW, Blacks and Hispanics have 1.5 to 3 times higher
proportion of uninsured individuals, which can contribute to difficulties in access to
professional treatment
12
. Similarly, to other diseases, the mortality of GBC, gallstones,
and other gallbladder-related diseases, has been reported to be inversely proportional to
educational attainment or other educational-related factors across all racial and ethnic
groups
20
.
In this study, disparities were observed regarding to sociodemographic, clinical
characteristics and survival when comparing Hispanic population to non-Hispanic
populations.
In general, females have been reported to have higher incidence rate of developing GBC
than males. A previous study of GBC in New Mexico State reported that the incidence
ratio of Hispanic female to Hispanic males was 3.3
21
. Similar situation was observed in
California where the incidence ratio GBC of female to male was 1.67 regardless of ethnic
groups and nativity. In our study, we did not estimate incidence rates by gender. However,
we did observe that compared to other racial/ethnic groups, FB Hispanics had a greater
proportion of female’s cases.
Cancer extension during first diagnosis can be an indication of early or late access
to healthcare system and hospitals for diagnosis. Also, the TNM system was used to
conclusively described the tumor status by three factors: the size and extent of the main
tumor, number of nearby lymph node that have cancer and whether its metastasized
22
.
When considering grade and stage at diagnosis we observed that FB Hispanics, USB

29
Hispanics, and NHB had the highest proportion of tumors diagnoses with either advanced
grade or stage. Similarly, these groups, along with FB Asians had the greatest proportion
of tumors diagnosed with larger size. Altogether, these finding suggests a greater
proportion of delayed diagnoses among these three populations. There are many reasons
can cause this high proportion of delayed diagnoses, such as barriers to access
healthcare, lack of insurance, low socioeconomic status. In addition, this high proportion
of delayed diagnoses in FB cases can also be due to their immigrant identities, and
language barriers.
NHB and Hispanic patients did not seem to differ in survival compared to NHW
patients. We observed that with increasing age, the survival rate decreases, and that
overall, patients with insurances were more likely to survive from GBC than uninsured
cases; however, cases with Medicaid were more likely to die compared to uninsured
cases. In addition, income status was also a determinant for survival with patients with
high SES and middle SES cases being more likely to survive GBC compared to low SES
cases. Interestingly, even though more than half of FB Hispanic patient population falls
into the low SES category, their survival did not seem to differ from NHW. Similarly, we
observed that survival rate decreased with advanced cancer stage. Even though FB
Hispanics had the highest proportion of advance stage at first diagnosis compared to
other racial/ethnic and nativity groups, their survival did not differ from NHW.
Among the strengths of our study is the utilization of the CCR, a population-based
resource with large numbers of GBC data in California. Given that this is a relatively rare
cancer, this dataset allows the analysis of multiple socio-demographic and clinical
variables available in the CCR. This can help us to assess some neglected variables in

30
previous studies which might correlated with the incidence and survival of GBC,
especially in the Hispanic population. In addition, we considered nativity of Hispanics and
Asians in our analyses, which allowed us to revel possible disparities between USB cases
and FB cases. Some limitations of this study need to be noted. One is that there are large
numbers of individuals with missing stage variable, as well as data on lymph nodes and
metastasis data.
Using the California Cancer Registry data, we report that among all cases
diagnosed between 1990-2018, FB Hispanic patients seemed to be diagnosed with more
adverse characteristics and at a younger age. Similarly, NHB patients also showed a
greater proportion of cases diagnosed at more advanced stage. Despite these
differences, neither of these groups showed disparities in survival compared to NHW
patients. Instead, we report that Asian patients showed improved survival compared to
NHW patients. There was a large percent of the Hispanic patient population with
unemployment, low SES, and uninsured status, which may become barrier for patients to
access diagnosis and treatment and may explain the greater proportion of diagnosis at
more advanced stage and grade.

31
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terms/def/differentiation. Accessed 28 Aug.

Abstract (if available)

Abstract Background: The incidence of gallbladder, intra-hepatic bile duct, and biliary cancers (we collectively refer to them as GBC henceforth) is low, but due to vague symptoms and lack of proper screening technologies, the mortality rate is high. The determinants of GBC are not clear, although there are some putative risk factors. There are very few population-based studies of GBC, especially focused on the Hispanic population, where the incidence is high. ❧ Methods: Using California Cancer Registry Data (CCR) from 1990–2018 we evaluated demographic and clinical characteristics of patients, such as stage, treatment status, and survival rate, and compared across racial/ethnic groups defined by nativity, which included: non-Hispanic whites (NHW), non-Hispanic Blacks (NHB), US born Hispanics, foreign-born Hispanics, US born Asians, and foreign-born Asians. Descriptive statistics, logistic regression, and Cox regression were used. ❧ Results: We included 37,393 patients’ records in the study. Statistically significant differences in frequencies were observed for all sociodemographic characteristics across racial/ethnic groups defined by nativity. Specifically, when considering age, NHB (50%), USB Hispanic (49.2%) and FB Hispanic (56.0%) patients had almost doubled proportion of diagnosis younger than 69 years old than NHW (35.7%). More than half of these population fall into low socioeconomic status (SES) category and FB Hispanic patients had the largest proportion of individuals without insurance (6.4%), which was 6 times compared to NHW (0.9%). Compared to NHW (10.6%), NHB (11.4%), USB Hispanic (8.8%), USB Asian (8.7%) and FB Asian (10.8%) patients, there were more FB Hispanic patients (12.9%) with remote metastasis at the time of diagnosis (p<0,001). FB Hispanic patients also had the greatest proportion of diagnoses with regional organ involvement and tumor size over 5 centimeters. In addition, FB Hispanic patients (1.64%) had the largest proportion of not receiving treatment compared to NHW (0.9%) and NHB (0.7%) patients (p<0.001). Patients who had older age and had middle SES, had higher likelihood of receiving treatment. Among all GBC cases in this study, NHB, USB Hispanics, and FB Hispanics did not statistically significantly differ from NHW in their risk of dying of GBC and related cancers. In contrast, US born and foreign-born Asian patients had lower risk of dying of GGBC and related cancers than NHW patients. With increasing in age, the chance of dying from GBC increases. Survival chances were inversely correlated with advance in cancer stage. ❧ Conclusion: Between 1990–2018, disparities in GBC and related cancers across racial/ethnic groups in California were observed in our study. FB Hispanic patients had greater proportion of individuals diagnosed with GBC when younger than 69 years old, greater proportion of individuals with low SES, greater proportion of diagnoses with remote extension of the tumor, and were less likely to receive treatment. Despite these differences, neither of these groups showed disparities in survival compared to NHW cases. Instead, we observed that Asian patients were less likely to die of GBC and related cancers compared to NHW cases. The observed large percent of Hispanic patients with unemployment, low SES, and uninsured status, which can all act as barriers for accessing diagnosis and treatment, may explain the greater proportion of diagnosis at more advanced stage and grade in this population.

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Asset Metadata

Creator Yang, Qiyu (author)

Core Title Disparities in gallbladder, intra-hepatic bile duct, and other biliary cancers among multi-ethnic populations: a California Cancer Registry study

School Keck School of Medicine

Degree Master of Science

Degree Program Molecular Epidemiology

Degree Conferral Date 2021-12

Publication Date 11/22/2021

Defense Date 11/21/2021

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag California Cancer Registry,gallbladder cancer,Hispanics,OAI-PMH Harvest,population-based

Format application/pdf (imt)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Stern, Mariana Carla (committee chair), Liu, LiHua (committee member), Setiawan, Veronica Wendy (committee member)

Creator Email qiyuyang@usc.edu,qyyang31@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-oUC17239459

Unique identifier UC17239459

Legacy Identifier etd-YangQiyu-10253

Document Type Thesis

Format application/pdf (imt)

Rights Yang, Qiyu

Type texts

Source 20211124-wayne-usctheses-batch-900-nissen (batch), University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

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Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA

Repository Email cisadmin@lib.usc.edu