Understanding Racial and Ethnic Differences in Survival from Colorectal Cancer


Despite improvements in overall case-fatality rates over the past two decades, disparities in survival from colorectal cancer particularly between Blacks and Whites have continued to increase. The causes of these disparities remain unclear. Given that colorectal cancer is preventable and potentially curable, it is imperative to identify the underlying causes of racial and ethnic differences in survival. The goal of this proposal is to identify potentially modifiable contributing factors to disparities in survival from colorectal cancer that may be amenable to system-based interventions.

Few studies have examined outcomes for colorectal cancer in racially diverse populations with health insurance coverage. Cancer Research Network-affiliated health care systems have stable enrolled racially and geographically diverse populations from varying socioeconomic backgrounds including patients younger than 65 years. These settings provide a unique laboratory in which to examine influences on colorectal cancer survival that are independent of the effects of health care insurance.

##Study Aims

The specific aims of this proposed project are to:

1. Compare colorectal cancer survival rates by race and ethnicity over the period 1993 through 2004.

2. Compare the distribution of tumor stage at diagnosis for colorectal cancer by race and ethnicity.

3. Examine potential mediators of the relationship between race/ethnicity and survival among colorectal cancer patients, including:

a) Patterns of colorectal examinations before cancer diagnosis

b) Patterns of cancer-directed therapy after cancer diagnosis

c) Burden of chronic medical conditions around the time of diagnosis.

4. Examine the patterns of care of survivors of colorectal cancer.

5. Explore the influence of socioeconomic status on the relationship between race/ethnicity and survival among patients with colorectal cancer.


This proposed project will be conducted on a large multi-racial cohort of patients diagnosed with carcinoma of the colon and rectum between 1993 and 2005 while enrolled at one of 4 health care systems affiliated with Cancer Research Network, by expanding the current Cancer Research Network racial disparities dataset. The sites have been selected to include those affiliated with health care systems with relatively large proportions of non-White members. Colorectal cancer patients will be identified through the sites’ electronic tumor registries and linked to information in electronic administrative databases. Within this cohort, the influence of race/ethnicity on stage at diagnosis and survival and examine potential mediators of survival disparities we will quantify.


This proposal will improve the understanding of racial disparities by examining aspects of the clinical care of patients with colorectal cancer that may contribute to disparities, including patterns of use of emerging technologies.

##Project Status

This is an NCI mentored career development project and Chyke Doubeni, MD, MPH is PI. The PI is mentored by several senior investigators within and outside the Cancer Research Network including Dr. Terry Field and Robert Fletcher. Dr. Doubeni is currently working with a variety of data from several sources including the NIH-AARP study, MCBS, NHIS, the US Census Bureau, Area resources File (AHRQ) Qualitative Data from key informants, and PLCO. Manuscripts are currently being developed around the incidence and mortality from CRC, the use of CRC screening services.

This is a cross-cutting project that involves primary data collection, studies of the effectiveness of cancer screening, and the use of cancer prevention services. Dr. Doubeni also conducts research on youth tobacco research under the auspices of this career development program focused on the influence of environmental factors on smoking initiation.

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