RECTAL CANCER - University of Southern California

RECTAL CANCER

Cancer in Los Angeles County: Rectal Cancer Incidence, Mortality and Survival 2000-2017.

Cancer in Los Angeles County: Rectal Cancer Incidence, Mortality and Survival 2000-2017

Amie Eunah Hwang, PhD Kai-Ya Tsai, MSPH

James Huynh Lihua Liu, PhD

Heinz-Josef Lenz, MD Dennis Deapen, DrPH

Design By: Hinde Kast

Suggested Citation:

Hwang AE, Tsai KY, Huynh J, Liu L, Lenz H-J, Deapen D. Cancer in Los Angeles County: Rectal Cancer Incidence, Mortality and Survival 2000-2017. Los Angeles Cancer Surveillance

Program, Norris Comprehensive Cancer Center, University of Southern California, 2020.

Copyright© 2020 by the University of Southern California.

All rights reserved.

This document, or parts thereof, may be reproduced in any form with citation.

CANCER IN LOS ANGELES COUNTY:

RECTAL CANCER

Los Angeles Cancer Surveillance Program USC/Norris Comprehensive Cancer Center

The Keck School of Medicine of the University of Southern California

CSP website: https://csp.usc.edu

Cancer data access portal for Los Angeles County + all California

https://explorer.ccrcal.org/

https://csp.usc.edu/

https://urldefense.com/v3/__https:/explorer.ccrcal.org/__;!!LIr3w8kk_Xxm!61fQJrUNQ0af2iB4ntqMSy8Ro6aat5uKqhnRocB3GoVmR4zxagNQ3q5FKqSt70Cx-Xs$

PREFACE………………………………………………………………….………1

EXECUTIVE SUMMARY.…………………………………………...…….……2

HISTORICAL BACKGROUND OF THE CSP………………………….……3

ACKNOWLEDGEMENT……………………………………………….………4

RECTAL CANCER STATISTICS……………………………………………...5

Incidence…………………………………………………………………………………….…….5

Mortality………………………………………………………………………….…………….. 12

Survival……………………………………………………………………….………………….16

SUMMARY OF RECTAL CANCER RISK FACTORS……………………..22

Modifiable Risk Factors…………………………………………………………………….…………….22

Non-modifiable Risk Factors……………………………………………………………….…………….23

SUPPLEMENTAL MATERIAL...............................……………….…...…...25

The Diverse Population of Los Angeles County…………………………………………….……….…..25

How Cancer is Registered……………………………………………………………………….....……..26

The Use of CSP Data for Research…………………………………………………………….…….…...26

The Importance of Investigating Time Trends and Survival………………………....….……...…….…27

Protection of Confidentiality………………………………………………………………………....…..28

Cancer Data…………………………………………………………………………………………..…...28

Statistical Methods…………………………………………………………………………………....…..29

Cautions in Interpretations…………………………………………………………………………....….30

Table of Contents


Preface 1

As the most populous county in the United States with more than 10 million racially and ethnically

diverse residents, Los Angeles County is an ideal place for cancer research. The vast disparities in cancer

risk among different population groups provide excellent opportunities to gain better understanding

about the potential causes of each type of cancer in order to develop better cancer control and prevention

strategies. It was for this very reason a group of visionary faculty researchers in the University of

Southern California Medical School (now the Keck School of Medicine) established the Los Angeles

Cancer Surveillance Program (CSP).

For the past 50 years, the CSP has become a leader on the national and international stages for cancer

surveillance and cancer epidemiological research with multitudes of contributions to the field. The CSP

cancer data and its diverse demographics are a gold mine of information for not only scientific research,

teaching and training the next generation of public health professionals, but also for serving the

community needs and building academic and community partnerships.

The CSP is a valued member and strong partner of the Norris Comprehensive Cancer Center whose

aim is to make cancer a disease of the past, for which the CSP data plays a significant role. Likewise, the

CSP is able to leverage the expertise of Cancer Center scientists to ensure data are well used to achieve

cancer prevention and control. The CSP also partners with the Keck School of Medicine, the University

of Southern California, and the larger communities beyond. CSP informational reports like this one

underscore the CSP’s commitment to serving its local communities for the ultimate goal of improving

cancer prevention, detection, treatment, and survival.

This report was prepared by the following researchers: Amie E. Hwang, PhD, cancer epidemiologist

and Assistant Professor; Kai-Ya Tsai, statistician; James Huynh, research assistant; Lihua Liu, PhD,

director and Associate Professor; Heinz-Josef Lenz, MD, clinical oncologist, Professor; Dennis

Deapen, DrPH, epidemiologist and Professor.


Executive Summary 2

Colorectal cancer is the third most commonly diagnosed cancer among men and the second

most common among women in Los Angeles County. Rectal cancer accounts for about 30% of colorectal cancers. Taken separately, rectal cancer alone is the 9th most common cancer for both men and women. Over 1,100 people are newly diagnosed with rectal cancer every year in Los Angeles County. Rectal cancer occurs most frequently in the older population with an incidence rate of 26 per 100,000 for 50-64 year olds and 52 per 100,000 for 65+ year olds. Due to active screening program for those 50 years of age or older, localized disease is more common in the older population, but younger patients are more frequently diagnosed with distant disease for whom screening recommendations are lacking. Incidence of rectal cancer is higher in several Asian Pacific Islander subgroups such as Hawaiian/Samoans and Japanese. Incidence rates of this cancer have steadily declined since 2000, most notably for localized diseases. Non-Hispanic Blacks experience excess burden of rectal cancer as they have highest proportion of distant disease and the highest rate of mortality. Compared to Non-Hispanic Whites, risk of dying for Non-Hispanic Black male patients is 23% higher and for Hawaiian/Samoan male patients is 44% higher. All other Asians/Pacific Islander groups and Hispanics have lower mortality than non-Hispanic Whites. Mortality rates have also declined significantly for those over 65 years of age, but have remained stable for the other age groups. Risk for rectal cancer is increased with an excess weight, sedentary lifestyle, red meat consumption, smoking, and alcohol intake. Those with family history of colon cancer or adenomatous polyps, Lynch syndrome and inflammatory bowel disease are also at elevated risk of colon cancer.

In order to provide the most comprehensive yet precisely focused information for the broader community, we provide the colorectal cancer statistics in three publications independently focused on colon cancer, rectal cancer and combined colorectal cancer. We recommend that the readers refer to the other publications to serve their specific needs (“Cancer in Los Angeles County: Colon Cancer Incidence, Mortality and Survival 2000-2017” and “Cancer in Los Angeles County: Colorectal Cancer Incidence, Mortality and Survival 2000-2017”).


The Los Angeles Cancer Surveillance Program (CSP) is the population-based cancer registry for Los

Angeles County. It identifies and obtains information on all new cancer diagnoses made in the County.

The CSP was organized in 1970 and operates within the administrative structure of the Keck School of

Medicine and the Norris Comprehensive Cancer Center of the University of Southern California. In

1987, it became the regional registry for Los Angeles County for the then new California Cancer

Registry. The CSP is one of 3 such regional registries collectively providing statewide cancer surveillance.

In 1992, the CSP joined the National Cancer Institute’s Surveillance, Epidemiology and End Results

(SEER) program. This consortium of 16 population-based SEER registries provides the federal

government with ongoing surveillance of cancer incidence and survival in the U.S. To date, the CSP

database contains more than 1.7 million records, and about 47,000 incident cancers are added annually.

The CSP is one of the most productive cancer registries in the world in terms of scientific contributions

toward understanding the demographic patterns and the causes of specific cancers. The CSP has a

bibliography of more than 10,000 publications in scientific journals. The registry supports a large

ongoing body of research funded mainly by the U.S. National Cancer Institute, other cancer research

organizations, and the State of California.

Historical Background of the CSP 3


The collection of cancer incidence data used in this study was supported by the California Department

of Public Health pursuant to California Health and Safety Code Section 103885; Centers for Disease

Control and Prevention’s (CDC) National Program of Cancer Registries, under cooperative agreement

5NU58DP006344; the National Cancer Institute’s Surveillance, Epidemiology and End Results

Program under contract HHSN261201800032I awarded to the University of California, San Francisco,

contract HHSN261201800015I awarded to the University of Southern California, and contract

HHSN261201800009I awarded to the Public Health Institute. The ideas and opinions expressed

herein are those of the authors and do not necessarily reflect the opinions of the State of California,

Department of Public Health, the National Cancer Institute, and the Centers for Disease Control and

Prevention or their Contractors and Subcontractors.

This work would not be possible without the work and dedication of CSP field technicians, other CSP

staff members, and cancer registrars across Los Angeles County and beyond.

Amie Hwang Kai-Ya Tsai James Huynh

Lihua Liu Heinz-Josef Lenz Dennis Deapen

Acknowledgement 4



Table 1. Frequency and Distribution of Invasive Rectal Cancer Cases by Sex, Age, Race/Ethnicity, Socioeconomic Status and Disease Stage, Los Angeles County, 2000-2017.

Male Female Male and Female N % N % N %

Age (years) 0-39 399 4 317 4 716 4 40-49 1,216 11 924 10 2,140 11 50-64 4,316 38 3,106 35 7,422 37 65+ 5,425 48 4,620 52 10,045 49

Race/Ethnicity

Non-Hispanic White 4,873 43 3,965 44 8,838 43 Non-Hispanic Black 1,055 9 954 11 2,009 10 Hispanic 3,115 27 2,299 26 5,414 27 Asian/Pacific Islander 2,152 19 1,629 18 3,781 19 Other/Missing 161 1 120 1 281 1

Asian/Pacific Islander Ethnicity Chinese 565 5 426 5 991 5 Japanese 320 3 224 2 544 3 Filipino 480 4 354 4 834 4 Korean 384 3 298 3 682 3 Vietnamese 142 1 125 1 267 1 South Asian 72 1 30 0 102 1 Thai/Hmong/Cambodian/Laotian 70 1 64 1 134 1 Hawaiian/Samoan 33 0 20 0 53 0

Socioeconomic Status High 2,110 19 1,708 19 3,818 19 Mid-High 2,283 20 1,911 21 4,194 21 Middle 2,224 20 1,751 20 3,975 20 Mid-Low 2,423 21 1,900 21 4,323 21 Low 2,316 20 1,697 19 4,013 20

Disease Stage Localized 4,554 40 3,766 42 8,320 41 Regional 3,814 34 2,784 31 6,598 33 Distant 2,030 18 1,479 17 3,509 17 Unknown 958 8 938 10 1,896 9

A total of 20,323 patients were diagnosed with rectal cancer from 2000-2017 in Los Angeles County. 86%

of the patients were 50 years of age or older at diagnosis. 43% of the patients were Non-Hispanic Whites.

Rectal Cancer Statistics 5

INCIDENCE

Figure 1. Disease Stage Distribution of Invasive Rectal Cancer by Age, Race/Ethnicity

and Socioeconomic Status, Los Angeles County, 2000-2017.

0%

10%

20%

30%

40%

50%

60%

Prop

ortio

n of

cas

es

Figure 1B. Distribution of Disease Stage by Race/Ethnicity

Localized Regional Distant


0%

10%

20%

30%

40%

50%

Age 0-39 Age 50-64 Age 65+

Prop

ortio

n of

cas

es

Figure 1A. Distribution of Disease Stage by Age

Age 40-49



Figure 1. Disease Stage Distribution of Invasive Rectal Cancer by Age, Race/Ethnicity

and Socioeconomic Status, Los Angeles County, 2000-2017.

0%

10%

20%

30%

40%

50%

60%

Highest Upper-Middle Middle Lower-Middle Lowest

Prop

ortio

n of

cas

es

Figure 1C. Distribution of Disease Stage by Socieconomic Status


Distant disease is more common among younger patients and localized disease is more common

among older patients.

Non-Hispanic Blacks have the highest proportion of distant disease. Hawaiian/Samoans have

the highest regional diseases.

Patients of higher socioeconomic status are diagnosed with localized diseases more frequently.

Distribution of disease stage is similar between different socioeconomic status.



Table 2A. Age-Adjusted Incidence Rates of Invasive Rectal Cancer by Sex, Age,

Race/Ethnicity and Disease Stage (per 100,000 population), Los Angeles County, 2000-2017.


The incidence of rectal cancer is the highest in the older males. Hispanics have lower incidence than other

race/ethnic groups. Patients are diagnosed with localized and regional diseases more frequently than

distant diseases.

Male Female Male and Female Total 15.0 9.7 12.1 Age (years)

0-39 0.8 0.6 0.7 40-49 9.5 7.1 8.3 50-64 31.1 20.7 25.7 65+ 66.7 41.0 51.9

Race/Ethnicity Non-Hispanic White 14.8 10.4 12.4 Non-Hispanic Black 15.5 10.4 12.6 Hispanic 13.6 7.9 10.4 Asian/Pacific Islander 17.4 10.4 13.5

Asian/Pacific Islander Ethnicity Chinese 14.2 8.8 11.3 Japanese 22.4 12.1 16.6 Filipino 18.1 9.0 12.5 Korean 19.8 12.0 15.4 Vietnamese 18.5 14.1 16.1 South Asian 9.6 4.0 6.8 Thai/Hmong/Cambodian/Laotian 15.1 10.3 12.5 Hawaiian/Samoan 32.4 15.0 21.7

Disease Stage Localized 6.0 4.1 4.9 Regional 5.0 3.0 3.9 Distant 2.6 1.6 2.1


Table 2B. Incidence Rate Ratio for Invasive Rectal Cancer by Sex and Race/Ethnicity,

Los Angeles County, 2000-2017.

Male Female Male and Female Race/Ethnicity

Non-Hispanic White (Reference) 1.00 1.00 1.00 Non-Hispanic Black 1.05 1.00 1.01 Hispanic 0.92 0.76 0.83 Asian/Pacific Islander 1.18 1.00 1.08


Localized disease occurs more frequently than regional and distant disease.

Hawaiian/Samoan and Japanese males experience the highest incidence and South Asians females the

lowest. Compared to Non-Hispanic White males, Hawaiian/Samoan males have more than two-fold

risk of rectal cancer and Japanese males have 52% increased risk.



Figure 2. Annual Age-Adjusted Incidence Rate Trends of Invasive Rectal Cancer by Disease Stage, Race/Ethnicity and Sex (per 100,000), Los Angeles County, 2000-2017.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Inci

denc

e Ra

te

Year of Diagnosis

Figure 2A. Annual Age-Adjusted Incidence Rate Trends by Disease Stage


0.0

5.0

10.0

15.0

20.0

25.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Inci

denc

e Ra

te

Year of Diagnosis

Figure 2B. Annual Age-Adjusted Incidence Rate Trends by Race/Ethnicity among Males

Non-Hispanic White Non-Hispanic Black Hispanic Asian Pacific Islander



Figure 2. Annual Age-Adjusted Incidence Rate Trends of Invasive Rectal Cancer by Disease Stage, Race/Ethnicity and Sex (per 100,000), Los Angeles County, 2000-2017.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Inci

denc

e Ra

te

Year of Diagnosis

Figure 2C. Annual Age-Adjusted Incidence Rate Trends by Race/Ethnicity among Females


The downward trend of incidence is more prominent for localized rectal cancer. There is a recent increase

of regional rectal cancer after 2014. While most racial/ethnic groups experienced decrease in risk of rectal

cancer over time, risks for Hispanics remained unimproved.



Table 3A. Age-Adjusted Mortality Rates of Rectal Cancer by Sex, Age, and Race/Ethnicity (per

100,000 population), Los Angeles County, 2000-2017.

The highest rectal cancer mortality rate is observed among Non-Hispanic Black males and

Hawaiian Samoan males. The lowest rectal cancer mortality is observed among Hawaiian/

Samoan females. Due to potential underestimation of rates in South Asians, South Asian data

should be interpreted cautiously (see Stastical Method).


MORTALITY

Male Female Male and Female Total 3.2 1.9 2.5 Age (years)

0-39 0.1 0.1 0.1 40-49 1.6 1.0 1.3 50-64 5.6 3.2 4.3 65+ 16.3 10.0 12.7

Race/Ethnicity Non-Hispanic White 3.3 2.1 2.6 Non-Hispanic Black 4.6 2.6 3.4 Hispanic 2.8 1.5 2.1 Asian/Pacific Islander 3.0 1.8 2.3



Table 3B. Mortality Rate Ratios for Rectal Cancer by Sex and Race/Ethnicity,

Los Angeles County, 2000-2017.

Male Female Male and Female Race/Ethnicity

Non-Hispanic White (Reference) 1.00 1.00 1.00 Non-Hispanic Black 1.40 1.22 1.28 Hispanic 0.87 0.72 0.79 Asian/Pacific Islander 0.91 0.86 0.88


Non-Hispanic Black males and Hawaiian/Samoan males experience 36-40% increased risk of dying

from rectal cancer compared to Non-Hispanic Whites. Hawaiian/Samoan females have 50% reduced

risk of dying from rectal cancer compared to the Non-Hispanic Whites.



Figure 3. Annual Age-Adjusted Mortality Rate Trends of Rectal Cancer by Age,

Race/Ethnicity and Sex (per 100,000), Los Angeles County, 2000- 2017.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Mor

talit

y Ra

te

Year of Death

Figure 3A. Annual Age-Adjusted Mortality Rate Trends by Age

Age 0 to 39 Age 40 to 49 Age 50 to 64 Age 65+

Rate of dying from rectal cancer has decreased significantly for older population, but for those under age 64,

the mortality rates have not improved over time.



0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Mor

talit

y Ra

te

Year of Death

Figure 3C. Annual Age-Adjusted Mortality Rate Trends by Race/Ethnicity among Females


0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Age-

Adju

sted

Mor

talit

y Ra

te

Year of Death

Figure 3B. Annual Age-Adjusted Mortality Rate Trends by Race/Ethnicity among Males


The downward trend in mortality due to rectal cancer is observed among Non-Hispanic Blacks. The

mortality trends have remained similar for the other race/ethnic groups over time.



Table 4. One- and Five-year Observed Survival from Invasive Rectal Cancer by Sex, Age, Race/Ethnicity,

Socioeconomic Status and Disease Stage, Los Angeles County, 2000-2017.

The highest 5-year observed survival from rectal cancer is among South Asians and the lowest is among Non-Hispanic Blacks and

Hawaiian/Samoans.


SURVIVAL

1 Year Survival (%) 95% CI 5 Year

Survival (%) 95% CI

Sex Males 81.8 81.0-82.5 52.8 51.8-53.8 Females 82.1 1.30-82.9 56.2 55.1-57.3

Age (years) 0-39 87.6 84.8-89.9 62.1 57.9-65.9 40-49 90.2 88.9-91.4 65.4 63.1-67.5 50-64 88.8 88.0-89.5 65.1 63.9-66.3

65+ 74.8 73.9-75.6 43.8 42.7-44.8 Race/Ethnicity

Non-Hispanic White 80.0 79.1-80.8 52.5 51.3-53.6 Non-Hispanic Black 77.0 75.0-78.8 45.6 43.2-47.9 Hispanic 84.0 82.9-84.9 55.5 54.0-57.0 Asian/Pacific Islander 85.5 84.4-86.7 59.8 58.0-61.4

Asian/Pacific Islander Ethnicity Chinese 85.6 83.2-87.7 60.6 57.1-63.8 Japanese 81.5 78.0-84.6 56.9 52.4-61.1 Filipino 85.5 82.9-87.8 60.2 56.5-63.7 Korean 87.8 85.0-90.1 61.2 57.2-65.1 Vietnamese 86.7 81.9-90.3 59.0 52.2-65.1 South Asian 86.1 77.2-91.7 71.5 60.2-80.0 Thai/Hmong/Cambodian/Laotian 79.0 70.7-85.2 52.0 41.8-61.3 Hawaiian/Samoan 92.5 81.1-97.1 42.8 28.7-56.2

Socioeconomic Status High 86.1 84.9-87.1 61.2 59.5-62.8 Mid-High 83.6 82.4-84.8 57.4 55.7-59.0 Middle 80.6 79.3-81.9 53.2 51.5-54.8 Mid-Low 82.0 80.8-83.2 51.5 49.8-53.1 Low 80.2 78.9-81.5 50.1 48.4-51.8

Disease Stage Localized 93.0 92.5-93.6 75.0 73.9-76.0 Regional 88.4 87.6-89.2 56.7 55.3-58.0 Distant 53.5 51.8-55.2 11.1 10.0-12.3 Unknown 62.4 60.1-64.7 33.3 30.9-35.7

CI: Confidence Interval


Table 5. One- and Five-year Relative* Survival from Invasive Rectal Cancer by Sex, Age, Race/Ethnicity,

Socioeconomic Status and Disease Stage, Los Angeles County, 2000-2017.

Hawaiian/Samoan rectal cancer patients have the worst 5-year survival after accounting for expected survival

from other causes of death. South Asians have the highest.


1 Year Survival (%) 95% CI 5 Year

Survival (%) 95% CI

Sex Males 86.3 85.5-87.1 64.5 63.3-65.7 Females 86.4 85.5-87.3 67.4 66.0-68.7

Age (years) 0-39 91.0 88.5-93.0 65.0 60.7-69.0 40-49 92.2 90.8-93.3 69.2 66.8-71.4 50-64 90.7 90.0-91.4 70.6 69.3-71.9 65+ 80.7 79.7-81.6 60.7 59.2-62.2

Race/Ethnicity Non-Hispanic White 84.8 83.8-85.7 66.3 64.8-67.7 Non-Hispanic Black 82.1 80.0-84.1 57.4 54.4-60.3 Hispanic 87.5 86.4-88.5 64.2 62.4-65.9 Asian/Pacific Islander 89.5 88.3-90.6 68.8 66.8-70.7

Asian/Pacific Islander Ethnicity Chinese 89.7 87.2-91.8 71.6 67.6-75.2 Japanese 87.1 83.3-90.1 68.8 63.4-73.7 Filipino 89.3 86.6-91.4 68.1 63.8-72.0 Korean 91.6 88.8-93.7 69.2 64.5-73.4 Vietnamese 91.3 86.5-94.5 63.8 56.1-70.5 South Asian 89.8 80.4-94.8 78.6 65.5-87.1 Thai/Hmong/Cambodian/Laotian 79.0 70.1-85.5 58.2 47.0-67.8 Hawaiian/Samoan 92.8 79.6-97.6 49.2 32.5-63.9

Socioeconomic Status High 90.2 88.9-91.3 75.1 72.9-77.0 Mid-High 87.6 86.4-88.8 69.5 67.5-71.4 Middle 84.4 83.0-85.7 64.3 62.2-66.3 Mid-Low 85.6 84.3-86.8 61.8 59.8-63.7 Low 84.3 83.0-85.6 59.0 56.9-61.0

Disease Stage Localized 96.8 96.2-97.3 89.8 88.6-90.9 Regional 92.3 91.4-93.0 68.2 66.6-69.8 Distant 59.0 57.1-60.8 14.4 13.0-15.9 Unknown 70.0 67.3-72.6 45.6 42.2-48.8

*Relative survival estimates the probability of survival from cancer considering the chances of dying fromother causes. It is calculated as a ratio of the observed survival among cancer patients to the expectedsurvival from all causes of death.

CI: Confidence Interval


Figure 4. Annual 5-year Observed Survival Trends of Rectal Cancer by Age, Race/

Ethnicity and Sex, Los Angeles County, 2000-2017.

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

5-ye

ar S

urvi

val P

roba

bilit

ies

Year of Diagnosis

Figure 4A. Annual Survival Trends by Race/Ethnicity for Males


5-year survival probabilities for males have not improved substantially. 5-year survival is lower for Non-

Hispanic Black males compared to the other racial/ethnic groups.


10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

5-ye

ar S

urvi

val P

roba

bilit

ies

Year of Diagnosis

Figure 4B. Annual Survival Trends by Race/Ethnicity for Females


Although Non-Hispanic Black females had worse survival compared to the other racial/ethnic groups in the early 2000s, their survival improved over time t o a level similar to the other racial/ethnic groups.


Figure 5B. Kaplan-Meier Observed Survival Curves by Race/Ethnicity Among Males

Figure 5. Kaplan-Meier Observed Survival Curves for Invasive Rectal Cancer by Age, Race/Ethnicity and Sex, Los Angeles County, 2000-2017.

Figure 5A. Kaplan-Meier Observed Survival Curves by Age

Rectal cancer patients aged 65 or older have significantly worse survival than those

under age 65. The survival patterns are similar for all age groups under 65.



Survival disadvantage in Non-Hispanic Blacks with rectal cancer is observed in both males and

females. Asian/Pacific Islanders have the highest survival. The survival pattern for Non-

Hispanic White males is similar to that for Hispanic males, but the survival pattern for Non-

Hispanic White females is as low as that for Non-Hispanic Black females.

Figure 5C. Kaplan-Meier Observed Survival Curve by Race/Ethnicity Among Females


Figure 5. Kaplan-Meier Observed Survival Curves for Invasive Rectal Cancer by Age, Race/Ethnicity and Sex, Los Angeles County, 2000-2017.


Table 6. Hazard Ratio* of Invasive Rectal Cancer by Sex, Age, Race/Ethnicity, Socioeconomic Status and Disease Stage, Los Angeles County, 2000-2017.

Rectal cancer patients aged 65 and older are more than twice as likely to die compared to those younger than 40. Non-Hispanic Black males experience 18% higher risk of dying compared to Non-Hispanic White male patients. Lower socioeconomic status is associated with higher risk of dying.


Male Female Male and Female HR 95% CI HR 95% CI HR 95% CI

Sex Males (Reference) 1.00 Females 0.89 0.86-0.93

Age 0-39 (Reference) 1.00 1.00 1.00 40-49 0.99 0.82-1.19 0.93 0.75-1.15 0.97 0.84-1.12 50-64 1.17 0.99-1.38 1.13 0.93-1.38 1.16 1.03-1.32 65+ 2.55 2.16-3.01 2.70 2.24-3.27 2.64 2.33-2.98

Race/Ethnicity Non-Hispanic White (Reference) 1.00 1.00 1.00 Non-Hispanic Black 1.18 1.08-1.29 1.07 0.97-1.18 1.13 1.06-1.21 Hispanic 0.90 0.84-0.97 0.82 0.75-0.89 0.87 0.82-0.91 Asian Pacific Islander 0.83 0.77-0.89 0.74 0.68-0.80 0.79 0.75-0.83

Socioeconomic Status High (Reference) 1.00 1.00 1.00 Mid-High 1.21 1.11-1.32 1.05 0.96-1.15 1.14 1.07-1.21 Middle 1.35 1.24-1.47 1.12 1.02-1.23 1.25 1.17-1.33 Mid-Low 1.34 1.23-1.46 1.27 1.15-1.40 1.31 1.23-1.40 Low 1.40 1.28-1.53 1.23 1.1-1.36 1.32 1.24-1.42

Disease Stage Localized (Reference) 1.00 1.00 1.00 Regional 1.65 1.55-1.76 1.70 1.58-1.84 1.67 1.59-1.76 Distant 6.80 6.34-7.28 7.37 6.80-8.00 7.04 6.68-7.42 Unknown 3.27 2.99-3.59 3.60 3.26-3.97 3.43 3.21-3.67

*Hazard ratios (HR) obtained from multivariate Cox regression models adjusting for all variableslisted.HR: Hazard RatioCI: Confidence Interval


EXCESS WEIGHT Excess weight is a known risk factor for rectal cancer. Individuals with a higher body mass index (BMI) are at an increased risk. Every 5kg/m2 increase in BMI has been associated with an additional 9% increase in risk in men and a slight increase in women.1 It is estimated that a quarter of the population in Los Angeles and nearly 40% of all adults in the US are obese.2

SEDENTARY BEHAVIORS Physical inactivity throughout the day leads to a greater chance of developing rectal cancer, independent from obesity. Working in a sedentary occupation, such as an office job where most of the day is spent sitting, increased risk by 1.5 times when compared to those who worked in more active fields.3,4

RED MEAT AND PROCESSED MEATS The International Agency for Research on Cancer classifies processed meat as carcinogenic to humans and red meat as possibly carcinogenic. They concluded there was a strong positive association observed between the consumption of red meat or processed meat and colorectal cancer. Eating either on a regular basis may increase the risk of colorectal cancer by 17-18%. 5 Los Angeles ranked #1 in hot dog and sausage consumption in the US, consuming 31 million pounds in 2018. In the same year, 2.6 million Dodger dogs were consumed by Los Angeles County baseball fans.6

SMOKING Smoking is a known cause of multiple cancers. Long-term smoking increases the risk of rectal cancer by 50-70%.7 One-fifth of Black, Hispanic, and Asian males in Los Angeles are current smokers.2

ALCOHOL Alcohol intake increases risk of rectal cancer. This risk increases with the amount of alcohol consumed for both men and women.8

Heavy drinkers were found to have a nearly 50% greater

likelihood of developing rectal cancer than non-drinkers. 8 16% of adults in Los Angeles reported binge drinking (5 or more drinks for men, 4 or more for women) in the past month.2

Summary of Rectal Cancer Risk Factors 22

MODIFIABLE RISK FACTORS


FAMILY HISTORY AND INHERITED DISEASES Those with a family history of rectal cancer in a first-degree relative are at an 89% greater risk.9

Inherited diseases, such as familial adenomatous polyposis (FAP) and certain genetic mutations can also predispose a person to rectal cancer. If left untreated, nearly everyone with FAP will eventually develop into cancer of the colon or the rectum within their lifetime.10

INFLAMMATORY BOWEL DISEASE (IBD) IBD, such as Crohn’s disease or ulcerative colitis, elevates the risk for rectal cancer. 1.3% of adults in the US have IBD.11 Studies from around the world concluded that those with IBD were 2 times as likely to develop rectal cancer.12

RACE AND ETHNICITY Japanese-Americans, Native Hawaiians, and Ashkenazi Jews have a demonstrated higher risk of rectal cancer compared to Non-Hispanic Whites.13,14 Los Angeles County has one of the largest Jewish populations in the United States and a large Japanese-American and Pacific Islander population second only to Hawaii.15,16

REFERENCES


NON-MODIFIABLE RISK FACTORS

1. Renehan, Andrew G., et al. "Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies." The Lancet 371.9612 (2008): 569-578.

2. Los Angeles County Department of Public Health, Office of Health Assessment and Epidemiology. Key Indicators of Health by Service Planning Area (2017).

3. Lynch, Brigid M. "Sedentary behavior and cancer: a systematic review of the literature and proposed biological mechanisms." Cancer Epidemiology and Prevention Biomarkers19.11 (2010): 2691-2709.

4. Boyle, Terry, et al. "Long-term sedentary work and the risk of subsite-specific colorectal cancer." American Journal of Epidemiology 173.10 (2011): 1183-1191.

5. Bouvard, Véronique, et al. "Carcinogenicity of consumption of red and processed meat." The Lancet Oncology 16.16 (2015): 1599-1600.



6. The National Hot and Sausage Council. “Consumption Statistics from the National Hot Dog and Sausage Council.” Consumption Stats, NHDSC www.hot- dog.org/media/consumption-stats. Accessed 29 November 2019

7. Coyle, Yvonne M. "Lifestyle, genes, and cancer." Cancer Epidemiology 472.1 (2009): 25-56.8. Cho E, Smith-Warner SA, Ritz J, et al. "Alcohol intake and colorectal cancer: a pooled analysis of

8 cohort studies." Annals of Internal Medicine. 140.1 (2004): 603–13.9. Calvert, Paula M. and Harold Frucht. "The genetics of colorectal cancer." Annals of Internal

Medicine 137.7 (2002): 603-612.10. Sampson, Julian R., et al. "Autosomal recessive colorectal adenomatous polyposis due to inherited

mutations of MYH." The Lancet 362.9377 (2003): 39-41.11. Dahlhamer, James M., et al. "Prevalence of inflammatory bowel disease among adults aged≥ 18

years—United States, 2015." Morbidity and Mortality Weekly Report 65.42 (2016): 1166-1169.12. Xie, Jianlin and Itzkowitz, Steven H. "Cancer in inflammatory bowel disease." World Journal of

Gastroenterology 14.3 (2008): 378.13. Ollberding, Nicholas J., et al. "Racial/ethnic differences in colorectal cancer risk: the multiethnic

cohort study." International Journal of Cancer 129.8 (2011): 1899-1906.14. Boursi, Ben, et al. "The APC p. I1307K polymorphism is a significant risk factor for CRC in

average risk Ashkenazi Jews." European Journal of Cancer 49.17 (2013): 3680- 3685.15. Tighe, Elizabeth, et al. “Summary & Highlights- 2019”. The American Jewish Population Project

(2019): 04-0516. U.S. Census Bureau. American Community Survey, 2018 American Community Survey 5-Year

Estimates, Table B02001. U.S. Census website. Retrieved May 02, 2020


THE DIVERSE POPULATION OF LOS ANGELES COUNTY

Los Angeles County is the most racially/ethnically diverse county in the U.S. The number of residents

living in Los Angeles County exceeds 10 million, according to the 2018 population estimates. Hispanic

or Latino individuals account for 48.5% of the County’s total population, in contrast to 38.9% in

California and 17.8% in the U.S.1 The proportion of non-Latino whites in Los Angeles County is 26.3%,

as compared to 37.5% in California and 61.1% in the U.S.1 About 8.5% of U.S. Latinos, 8.3% of U.S.

Asian Americans, and 4.8% of U.S. Pacific Islanders live in Los Angeles County.1 People of multi-race

count for 3.9% of the County’s total population, much higher than the national average of 3.2%.1

The 1.4 million Asian Americans in Los Angeles County include 0.4 million Chinese, 0.3 million

Filipino, 0.2 million Korean, 0.1 million Japanese, 0.1 million Asian Indian and over 93,000

Vietnamese.1 Los Angeles County is also home to more than 28,000 Native Hawaiians and Other Pacific

Islanders.1

Among the 4.9 million self-reported Hispanics or Latinos in the County, 76% identify as Mexican, 8.4%

Salvadoran, 5.2% Guatemalan, 1.0% Puerto Rican, 0.8% Cuban, 1.0% Honduran, 0.9% Nicaraguan, and

2.8% South American.1

About 3.5 million Los Angeles County residents are foreign-born; 14.7% of them entered the country

since 2010.1 More than half (56.8%) of the total population five years of age or older speak a language

other than English.1

The 2.7 million non-Latino white population also has highly diverse origins. The population of

European origin includes large numbers of persons from Britain, Germany, Ireland, Italy, Russia,

France, and other parts of Europe. In the past 30 years the County experienced a substantial influx of

immigrants from Iran, Lebanon and the former Soviet Union. The Armenian community is estimated to

be nearly 200,000. Over 53,000 individuals of Arabic descent live in Los Angeles County.1

Every numerically important religious group in the U.S. is represented by sizable populations. There is

also a wide variation in socioeconomic and sociocultural characteristics of the County population.

Occupation and industry data reflect the diversity one would expect of a large urban metropolis. In

addition, Los Angeles County is characterized by geographic diversity, with regions of mountains,

valleys, deserts, and seashores.

With its large and diverse populations, Los Angeles County is an ideal place for monitoring cancer

occurrence and conducting epidemiological investigations.

Supplemental Material 25


HOW CANCER IS REGISTERED

Under the California model of reporting, a passive cancer surveillance system has been implemented

statewide, in which hospitals and other facilities where cancer is diagnosed or treated bear the

responsibility for identifying and reporting cancer cases to the local regional registry within six months

after the patient’s diagnosis or treatment. Pathologists diagnosing cancer are required to submit an

electronic copy of the pathology report within two weeks of diagnosis. Each hospital or other reporting

facility is required to complete a full report known as an abstract, including stage and treatment

information, on every cancer case seen at the facility. All completed abstracts are linked by to the

pathology reports to assure that one abstract is completed for each histologically-verified cancer

diagnosis. In addition, any previously unrecognized cancer diagnoses among Los Angeles County

residents, identified as a result of searching computerized death records, are traced back to patient

records in hospitals or other facilities so that data can be abstracted, when possible, in a similar way to

data found using pathology reports.

USE OF CSP DATA FOR RESEARCH

The CSP data serve as a descriptive epidemiological resource to generate new hypotheses regarding

specific cancer sites or histologic subtypes, monitor descriptive trends and patterns of cancer incidence,

and identify demographic subgroups at high risk of cancer. A high priority is always placed on

exploring demographic patterns and trends in cancer incidence among the racially and ethnically

diverse population of Los Angeles County.



THE IMPORTANCE OF INVESTIGATING CANCER TRENDS

To keep an eye on cancer ratesMonitoring cancer rates provides clues about what causes cancer. When we observe a change in the rate of

cancer that seems to follow a change in an environmental exposure, we consider the possibility of a link

between the exposure and cancer. For example, at the beginning of last century, increasing lung cancer

rates followed the introduction and increasing popularity of cigarettes and smoking.

To monitor improvements in cancer outcomesWhile cancer prevention is our ultimate goal, efforts are also focused on successful treatment. An ultimate

measure of treatment success is long-term survival, especially in the AYA age group with many more years

of life expectancy. We seek to identify the factors associated with long-term survival to benefit future

cancer patients.

To know whether cancer control efforts are workingWe also monitor cancer rates to provide a “report card” on how well cancer prevention programs work. We

generally expect that a successful intervention program, such as the introduction of the HPV (human

papillomavirus) vaccine should be followed by a decline in cervical and other HPV-related cancer rates.

To decide what resources are required to fight cancerBecause cancer is such an important health problem and is costly in terms of treatment and social costs,

such as loss of work time and quality of life, it is important to have a clear idea of the changing burden of

cancer on society. Government officials and policymakers use trends in cancer rates to determine funding

for screening, treatment and related social services, as well as to establish priorities for supporting effective

research into the causes and prevention of cancer and the development of treatments.

To see the effect of changes in cancer screening and detection methodsMany things can cause changes in cancer rates, including changes in the distribution of the factors that

cause the disease, changes in our ability to prevent or detect cancer early, changes in the population,

changes in diagnostic criteria to define a type of cancer, and even simple random variation.

To make cancer a disease of the past

Keeping an eye on cancer rates provides clues about the causes of cancer, how successful we are at

preventing cancer, and where we should focus our efforts in the future to make cancer a disease of the past.



PROTECTION OF CONFIDENTIALITY

Confidentiality procedures at the CSP are rigidly formulated and maintained. All employees of the

CSP sign a confidentiality pledge after being advised of the necessity for maintaining strict

confidentiality of patient information, and are shown methods to assure this. Confidentiality of

computerized data is assured by highly restricted access and protected by encryption. All reports and

summaries produced for distribution by the CSP, such as those presented here, are in statistical form

without any personal identifiers. All individual studies using confidential information obtained from

the registry are individually reviewed by the California Protection of Human Subjects Board. For

studies from outside investigators, review and approval by a federally approved institutional review

board is required.

CANCER DATA

Cancer data used in this report are based on new cancer cases diagnosed among the residents in Los

Angeles County from January 1, 2000 to December 31, 2017.

Cancer patients are grouped by sex (male, female), age (0-39, 40-49, 50-64, 65+ years old), race/

ethnicity (Non-Hispanic White, Non-Hispanic Black, Hispanic, Asian/Pacific Islander),

socioeconomic status (SES) (high, mid-high, middle, mid-low, low), and stage of disease at diagnosis

(localized, regional, distant). Asian/Pacific Islanders are further categorized as Chinese, Japanese,

Filipino, Korean, Vietnamese, South Asian that includes Indian, Pakistani, Sri Lankan, Nepalese,

Bhutanese, and Sikkimese, and Thai/Hmong/Cambodian/Laotian. Localized stage refers to cancer

that has not spread from original location. Regional stage refers to cancer that has spread beyond

original location to either nearby organs/lymph nodes, and distant stage refers to cancer that has spread

to other parts of the body.

The follow-up of cancer patients is conducted by the CSP through a combination of methods including

information sharing from the reporting hospitals, record linkage with vital statistics, Social Security

Administration, driver license information, and credit records. The follow-up information helps to

determine the vital status of a cancer patient, calculate the survival time, and estimate the survival rate of

the specific cancer.



STATISTICAL METHODS

We provide case count and percentage distribution of cancer cases by patient demographics and tumor

stage at diagnosis. In order to compare cancer risk levels among different groups, we calculate and

present the age-adjusted incidence rates and age-adjusted mortality rates by considering the number of

cancer occurrences and cancer related deaths, respectively, in relation to the size of the group’s at-risk

population. In order to preserve statistical stability of rate estimation and comply with the suppression

rules set by the California Cancer Registry (CCR), minimum case count of less than event threshold for

numerator is set at 11 is not shown in tables and not used for calculating rates. Annual population

estimates for 2000-2017 in Los Angeles County by aggregated racial/ethnic groups were provided by

the CCR based on the county level estimates by the National Center for Health Statistics. We

estimated the annual populations for Asian and Pacific Islander ethnic groups as identified in the 2000

and 2010 population censuses as well as the 2011-2015 American Community Survey 5-year Estimates

using linear interpolation and extrapolation. South Asian population included Asian Indians,

Pakistanis, Sri Lankans, Bangladeshis, and Nepalese. Because Bhutanese and Sikkimese, two small

population groups, are included in the incidence data but not in the population data, rate estimates for

South Asians may be overestimated slightly.

Observed survival is the actual percentage of patients still alive at some specified time after the diagnosis

of cancer. It considers deaths from all causes, cancer or otherwise. Relative survival estimates the

probability of survival from cancer after considering the chances of dying from other causes. It is

calculated as a ratio of the observed survival among cancer patients to the expected survival from all

causes of death using survival probabilities in the general population of same age group. Using non-

parametric Kaplan-Meier survival function, we calculated the observed survival at 5-years after

diagnosis by cancer type and stratified by sex, age, race/ethnicity, SES, and tumor stage. Graphs of the

estimates of the survival rate allow us to see how the survival probability changes over time and differs

by patient and tumor characteristics. We also estimated hazard ratio by comparing the probability of

deaths between age groups, race/ethnicity groups, SES and stage using multivariate Cox regression

model.

As with all population-based cancer registries, the CSP does not directly contact patients for follow-up.

The quality of follow-up information is critical to the survival evaluation. The accuracy of a patient’s

racial/ ethnic classification depends on the patient’s racial/ethnic identification recorded in the medical charts.



CAUTIONS IN INTERPRETATION

This information may be based on self-identification by the patient, on assumptions made by an

admission clerk or other medical personnel, or on an inference made using race/ethnicity of parents,

birthplace, maiden name or last name. Efforts that evaluate the data quality of population-based cancer

registries have concluded that misclassification of race/ethnicity may exist for a very small portion of the

registry records. The reliability of estimates for at-risk population may affect the cancer risk estimates.

Finally, special caution should be used when interpreting the meaning of the analyses that are based on

only a few cases. Calculations based on small numbers are statistically unstable.

REFERENCE

1. U.S. Census Bureau, 2014-2018 American Community Survey 5-Year Estimates.





Los Angeles Cancer Surveillance Program USC/Norris Comprehensive Cancer Center

The Keck School of Medicine of the University of Southern California

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RECTAL CANCER - University of Southern California