Socioeconomic and Racial Disparities in the Presentation of Advanced Colon Cancer in a Veterans Affairs Population: A Ten-Year Single Center Experience: Presidential Poster

Abstract

Purpose: Colorectal cancer (CRC) is the third leading cause of cancer death in the United States. We sought to study trend of CRC location over time and roles of race and SES in determining stage and location of CRC in a veteran population. Methods: Records were reviewed for patients diagnosed with CRC at VA Loma Linda during 1999-2009. Variables included age at diagnosis, sex, anatomic location, stage at diagnosis, race/ethnicity, SES quintiles (low, medium, high; using 2011 census block groups based on method described by Yost et al). Analysis was performed using SAS version 9.2. Results: A total of 600 patients (mean age at diagnosis 77.4 years), grouped as 580 males (97.1%), 17 females (2.9%); 126 blacks (21%), 388 whites (64.7%), 69 Hispanics (11.5%), 16 others (2.7%); 125 low SES (20.8%), 286 middle SES (64.3%), 89 high SES (14.8%), were included. At time of diagnosis, 109 (18.1%) patients were at stage I, 168 (28%) at stage II, 135 (22.5%) at stage III, and 188 (31.3%) at stage IV. Ten years were divided in three categories (t1=1999-2002, t2=2003-2005, t3=2006-2009) to study trends. During 10 years, there were 226 right-sided and 374 left-sided CRC. Controlling for time and race, right side was at non-significant higher risk of stage IV CRC (odds ratio [OR] 1.147; 95% confidence interval [CI] 0.805-1.635). Number of right-sided CRC during different time periods t1 (45) to t2 (58) and t3 (123) increased significantly (p for trend t2-t1=0.1753; t3-t2=0.0039; t3-t1=<0.0001). Number of stage IV CRC during different time periods 72 (t1), 55 (t2), and 61 (t3) decreased significantly (p for trend t2-t1=0.0346; t3-t2=0.0583; t3-t1<0.0001). Sorted by race, number of right-sided CRC increased in both blacks (p for trend t2-t1=0.0784; t3-t2=0.0135; t3-t1<0.0001) and whites (p for trend t2-t1=0.7484; t3-t2=0.0075; t3-t1=0.0239; p overall=0.0121). There was a significant decrease in stage IV CRC for blacks (p for trend t2-t1=0.1453; t3-t2=0.0764; t3-t1=0.0004; p overall=0.0003) and whites (p for trend t2-t1=0.1957; t3-t2=0.2883; t3-t1=0.1753; p overall=0. 0129). Low SES was more closely associated with black race and right side. With SES as a constant, poor blacks were at a higher risk of developing right-sided CRC compared to poor whites (OR 2.62; 95% CI=1.03-6.67). Also, poor blacks were more likely to have stage IV CRC compared to poor whites, but association was non-significant (OR=1.14; 95% CI=0.47-2.72). Conclusion: At our VA, there is a significant trend for diagnosis of more right-sided and less stage IV CRC over a 10-year time period. Low SES is associated with stage IV and right-sided CRC, but it is not as strong a predictor of location and stage as race is.Table 1: Trend of colorectal cancer location and cancer stage with timeTable 2: Trend of colorectal cancer stage with time period and stage IV with race