Abstract
PURPOSE: Although the number of medical oncologists (MOs) has steadily increased over time, and adjuvant chemotherapy provides significant survival benefit for patients with stage III colon cancer, many patients still do not receive chemotherapy. Uneven geographic distribution of MOs may contribute to decreasing access to cancer care. This study explored the association of MO availability by hospital service area (HSA) of patient residence and access to chemotherapy treatment. METHODS: Using the linked SEER-Medicare database, the study identified 9,262 patients who were age ≥66 years and underwent colectomy for stage III colon cancer diagnosed from 2000 to 2005. MOs were identified by physician specialty codes. HSAs are geographic areas that are relatively self-contained with respect to routine hospital care. Multivariate logistic regression was used to investigate the association between MO availability by HSA of patient residence and initiation of chemotherapy. RESULTS: Within 3 months after colectomy, 5,622 patients (60.7%) initiated chemotherapy. Adjusting for clinical and patient characteristics, patients residing in an HSA with ≥ one MO had an increased likelihood of initiating chemotherapy within 3 months after colectomy compared with those living in areas with no MOs (one to two MOs: OR, 1.451 [P < .01]; three to eight MOs: OR, 1.497 [P < .01]; ≥ nine MOs: OR, 1.322 [P < .01]). CONCLUSION: Results suggest that the availability of ≥ one MO within the HSA in which a patient resides was associated with greater access to chemotherapy after surgery.