Background: It is well recognized that stage III colon cancer patients who received chemotherapy postoperatively can have a reduced risk of recurrence and an improved survival rate. This study examined the impact of race/ethnicity and socioeconomic status (SES) on receipt of chemotherapy within 4 months after resection among stage III colon cancer patients enrolling in Medicare Parts A and B and trends of utilizing adjuvant chemotherapy.
Methods: Stage III colon cancer patients diagnosed between 2000 and 2007 were obtained from the Surveillance, Epidemiology, and End Results-Medicare data. Multilevel logistic regression was used to estimate the association between predictor variables and adjuvant chemotherapy, and the Cochran-Armitage test was used to assess for linear trends.
Results: Of 13,608 stage III colon cancer patients aged 66 and older, 56 percent received adjuvant chemotherapy within 4 months of surgical resection. Blacks or patients residing in the least affluent areas were less likely to receive the adjuvant chemotherapy within 4 months after resection, both before and after adjusting for race/ethnicity and other independent variables. A significantly decreasing trend was observed, from 58 percent in 2000 to 53 percent in 2007, for all patients combined. Trends of receiving chemotherapy within 4 months after resection were varied more in racial/ethnic groups than in SES groups.
Conclusions: After adjusting for demographic and clinical factors, there are persistent racial/ethnic and SES disparities in the use of adjuvant chemotherapy among Medicare-insured elderly patients with stage III colon cancer. The shortage of chemotherapy drugs and the change of Medicare drug administration reimbursement could be attributive factors in the decline of using adjuvant chemotherapy within 4 months of surgical resection.