Exploiting Diverse Data Sources to Examine Colorectal Cancer Disparities
Principal Investigator: Chyke A. Doubeni, MD, MPH
Department of Family Medicine and Community Health
Division of Preventive and Behavioral Medicine, Department of Medicine
University of Massachusetts Medical School
Worcester, Massachusetts 01655
What's the problem?
Death rates from colorectal cancer (CRC) are declining. However, racial and ethnic disparities in CRC death rates persist and are widening between Blacks and Whites. Racial and ethnic differences in screening rates also persist. The reasons for these differences have not been entirely elucidated. CRC develops through a well-established multistage process, and early identification and removal of precursor lesions can potentially prevent the disease. In addition, early stage tumors are curable. Therefore, it is important to understand why disparities in CRC screening, treatment, and mortality exist so that appropriate steps can be taken to ameliorate the problem.
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How is this research addressing the problem?
Using a variety of different data sources, Dr. Doubeni has shed light on the various factors that influence CRC screening, diagnostic follow-up, and treatment among different population groups. Three recent studies illustrate his work and show how he has confirmed previous findings as well as opened new areas of investigation.
In the first study, Dr. Doubeni and his team examined tumor stage and survival among CRC patients who received care at participating Cancer Research Network (CRN) health care systems. The CRN is a consortium of 14 research centers that are affiliated with integrated health care systems and that provide the full spectrum of cancer care, from screening to end-of-life care. Each of CRN system has a tumor registry that provided the data for analysis. Dr. Doubeni’s team found Black patients with CRC had a higher risk of dying than did Whites, whereas Asians/Pacific Islanders had a better chance of survival compared with Whites. The survival rates of Whites and Hispanics did not differ significantly. The survival difference between Blacks and Whites was explained by differences in tumor stage and receipt of surgical therapy. Confirming other studies, Dr. Doubeni’s team found that Blacks were less likely to be diagnosed through screening and that they were less like to receive cancer-related therapies compared with other racial and ethnic groups. However, the racial differences were smaller in this insured population that received care in an integrated health system than have been seen in other studies.
In a second study, using a different data set, Dr. Doubeni is examining socioeconomic and racial differences in CRC screening. In this analysis, he has used data from the Medicare Current Beneficiary Survey (MCBS), an ongoing annual survey of Medicare beneficiaries, to clarify complex socioeconomic patterns of disparities. He is exploring how education and income may relate to differences in use of CRC screening tests, and whether rates of testing among less educated individuals vary by type of health insurance.
In the third study, Dr. Doubeni and his team used yet another data set to examine another facet of this same issues of disparities. The Prostate, Lung, Colorectal, and Ovarian (PCLO) Cancer Screening Trial is an ongoing multicenter, randomized controlled trial designed to evaluate the influences of screening on cancer mortality. Because the PCLO contains data on diagnostic follow up of abnormal screening, it provided an opportunity for Dr. Doubeni to explore whether the higher CRC incidence and mortality among Blacks compared to Whites reflects differences in the use of health care services or CRC susceptibility. The researchers found lower rates of diagnostic follow up among Blacks compared to Whites, but no significant differences in the prevalence of different kinds of CRC pathology. This suggests that health care utilization may play more of a role than biology in CRC racial disparities.
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Significance of the research & results
Throughout his career, Dr. Doubeni has taken advantage of research opportunities to break new ground in understanding cancer screening and health disparities. Early in his career, Dr. Doubeni participated in the CRN Scholars Program at the University of Massachusetts Medical School, then conducted the MCBS study under an NIH K01 training award. Currently he is co-principal investigator on a NIH Grand Opportunities (GO) grant, which is examining cervical and CRC screening. He also serves as principal investigator on a competitively funded R01 grant that involves a larger number of institutions and a larger sample population. This grant will complement and extend the investigation of CRC screening beyond the GO grant.
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Recent related publications of interest
Laiyemo AO, Doubeni C, Pinsky PF, Doria-Rose P, Bresalier R, Lamerato LE, Crawford ED, Kvale P, Fouad M, Hickey T, Riley T, Weissfeld J, Schoen RE, Marcus PM, Prorok PC, Berg CD. Race and colorectal cancer disparities: Health-care utilization vs different cancer susceptibilities. Journal of the National Cancer Institute 2010;102(8):538-546. [View Abstract]
Doubeni CA, Laiyemo AO, Reed G, Field TS, Fletcher RH. Socioeconomic and racial patterns of colorectal cancer screening among Medicare enrollees in 2000 and 2005. Cancer Epidemiology, Biomarkers & Prevention 2009;18(8):2170-2175. [View Abstract]
Doubeni CA, Field ST, Buist DS, Korner EJ, Bigelow C, Lamerato L, Herrinton L, Quinn VP, Hart G, Hornbrook MC, Gurwitz JH, Wagner EH. Racial differences in tumor stage and survival for colorectal cancer in an insured population. Cancer 2007;109(3):612-620. [View Abstract]
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