Racial Disparities in Colon Cancer Survival Persist

Jeffrey H. Silber, M.D., Ph.D. The Nancy Abramson Wolfson Endowed Chair in Health Services Research Director, Center for Outcomes Research The Children's Hospital of Philadelphia Professor of Pediatrics, Anesthesiology & Critical Care The Perelman School of Medicine Professor of Health Care Management, The Wharton SchoolMedicalResearch.com Interview with:
Jeffrey H. Silber, M.D., Ph.D.

The Nancy Abramson Wolfson Endowed Chair in Health Services Research Director, Center for Outcomes Research
The Children’s Hospital of Philadelphia
Professor of Pediatrics, Anesthesiology & Critical Care
The Perelman School of Medicine
Professor of Health Care Management, The Wharton School
The University of Pennsylvania  Philadelphia, PA 19104

Medical Research: What is the background for this study? What are the main findings?

Response: Differences in colon cancer survival by race is a well recognized problem among Medicare beneficiaries. We wanted to determine to what extent the racial disparity in survival is due to a racial disparity in presentation characteristics at diagnosis (such as advanced stage and the presence of chronic diseases) versus a disparity in subsequent treatment by surgeons and oncologists.

To answer this question, we compared black colon cancer patients to three matched white groups:

(1) “Demographics” match controlling age, sex, diagnosis year, and Survey, Epidemiology, and End Results (SEER) site;
(2) “Presentation” match controlling demographics plus comorbidities and tumor characteristics including stage and grade; and
(3) “Treatment” match including presentation variables plus details of surgery, radiation and chemotherapy.

We studied Medicare patients 65 years of age and older diagnosed between 1991-2005 in the SEER-Medicare database. There were 7,677 black patients and 3 sets of 7,677 matched white controls.

We found that difference in 5-year survival (black-white) was 9.9% in the demographics match. This disparity remained unchanged between 1991-2005. After matching on presentation characteristics, this difference fell to 4.9%. Finally, after additionally matching on treatment, this same difference hardly changed, moving to only 4.3%. So the disparity in survival attributed to treatment differences comprised only an absolute 0.6% of the overall 9.9% survival disparity.

Medical Research: What should clinicians and patients take away from your report?

Response: Racial disparities in colon cancer survival did not decrease among patients diagnosed between 1991-2005. This persistent disparity appears far more related to presentation characteristics at diagnosis than subsequent treatment differences.

Medical Research: What recommendations do you have for future research as a result of this study?

Response: We need to find better ways to encourage black Medicare patients to be screened for colon cancer and to contact their primary care provider when they develop new symptoms. We also need to improve the primary care infrastructure in the United States to address the extreme racial disparity in the prevalence of chronic diseases that we observe.

Citation:

Racial Disparities in Colon Cancer Survival: A Matched Cohort Study

Jeffrey H. Silber, MD, PhD; Paul R. Rosenbaum, PhD; Richard N. Ross, MS; Bijan A. Niknam, BS; Justin M. Ludwig, MA; Wei Wang, PhD; Amy S. Clark, MD; Kevin R. Fox, MD; Min Wang, MHS; Orit Even-Shoshan, MS; and Bruce J. Giantonio, MD

Ann Intern Med. 2014;161(12):845-854. doi:10.7326/M14-0900