Patterns of Care for Metastatic Colorectal Cancer in Appalachia, and the Clinical, Sociodemographic, and Service Provider Determinants

Background: Appalachia has high colorectal cancer (CRC) incidence and mortality, at least in part due to screening disparities. This paper examines patterns and determinants of metastatic colorectal cancer care. Methods: CRC patients diagnosed in 2006-2008 from 4 cancer registries (Kentucky, Ohio, Pennsylvania, and North Carolina) were linked to Medicare claims (2005-2009.) The final sample after exclusions included 855 stage IV and 590 stages I-III patients with metachronous or synchronous metastases. We estimate bivariate and multivariate analyses for several surgical and chemotherapeutic strategies of care using clinical, sociodemographic, and contextual determinants. Results: Among 1,445 CRC patients, 84% had primary tumor resection and 44% received chemotherapy. Of the chemotherapy patients, 44% received newer systemic agents for at least 75% of the cycles. One year survivors with liver or lung metastases were more likely to have their primary tumor resected immediately (86.1% vs 69.5% for liver, and 78.2% vs 64.9% for lung) and have their metastases resected/ablated (15.7% vs 2.6% for liver and 15.0% vs 0.5% for lung). Patients with stages I-III primary tumors (versus IV) were much more likely to be resected, but they were less likely to receive chemotherapy. Patients with comorbidities (congestive heart failure, dementia, or respiratory disease) had lower odds of chemotherapy. Smaller hospital size and surgical volume had higher odds of immediate versus delayed surgery. The newer chemotherapeutic agents were more common with higher surgical volume. Conclusions: Metastatic colorectal cancer has clinical, sociodemographic, and service provider determinants.