#69 Racial and ethnic differences in bowel surveillance procedures following colorectal cancer surgery with curative intent

PURPOSE: Bowel surveillance with colonoscopy or barium enema is recommended for early detection of recurrences and metachronous tumors after colorectal cancer surgery with curative intent. There is a documented pattern of under-use coupled with some overuse of these procedures. Sociodemographic variation has been observed among those undergoing these procedures. The purpose of this analysis was to investigate racial/ethnic differences in postoperative bowel surveillance in a large population-based dataset: linkage of NCI Surveillance, Epidemiology, and End Results (SEER) cancer registry with Medicare data. METHODS: We analyzed data from 44,768 non-Hispanic white, 2,921 black, and 4,416 other patients, age 65 and over, who had a diagnosis of local or regional colorectal cancer between 1986 and 1996, and were followed through 12/31/98. Information about surgery and bowel surveillance with colonoscopy, flexible sigmoidoscopy, and barium enema was obtained from Medicare claims using ICD-9-CM and CPT-4 codes. RESULTS: We observed statistically significant racial/ethnic differences in time to first surveillance (p < 0.001). The chance of surveillance within 18 months of surgery was 57%, 48%, and 45% for non-Hispanic whites, blacks, and others, respectively. After adjusting for sociodemographic, hospital, and clinical characteristics in a Cox proportional hazards model, blacks were 13% less likely than non-Hispanic whites to undergo surveillance if diagnosed by 12/31/90 (RR = 0.87, 95% CI = 0.80–0.95) and 24% less likely if diagnosed between 1/1/91 and 10/31/96 (RR = 0.76, 95% CI = 0.70–0.82). CONCLUSION: Blacks, who have a 40% higher colorectal cancer mortality rate than non-Hispanic whites, were less likely than non-Hispanic whites to receive postoperative bowel surveillance. This result was not explained by measured racial/ethnic differences in sociodemographic, hospital, and clinical characteristics.