Adjuvant chemotherapy after resection in elderly Medicare and Medicaid patients with colon cancer

Background: This study investigated the influence of Medicaid enrollment on the receipt and completion of adjuvant chemotherapy and the likelihood of evaluation by an oncologist for those patients who do not initiate chemotherapy. Methods: Medicaid and Medicare administrative data were merged with the Michigan Tumor Registry to extract a sample of patients who had resection for a first primary colon tumor diagnosed between January 1, 1997, and December 31, 2000 (n = 4765). We used unadjusted and adjusted logistic regression to assess the relationship between Medicaid enrollment and the outcomes of interest. Results: Relative to Medicare patients, Medicaid patients were less likely to initiate chemotherapy (odds ratio, 0.50; 95% confidence interval, 0.39-0.65) or complete chemotherapy (odds ratio, 0.52; 95% confidence interval, 0.31-0.85). When the sample was restricted to patients with TNM-staged disease, Medicaid patients were less likely to initiate chemotherapy. Older patients and patients with comorbidities were also less likely to initiate or, in some cases, to complete chemotherapy. Conclusion: Medicaid enrollment is associated with disparate colon cancer treatment, which likely compromises the long-term survival of these patients.