Trends in Disparities in Receipt of Adjuvant Therapy for Elderly Stage III Colon Cancer Patients The Role of the Medical Oncologist Evaluation

Background: Race disparities in adjuvant chemotherapy for stage III colon cancer patients have been documented, and medical oncologist evaluation is a critical step in the treatment process. Recent healthcare system and environmental changes may have reduced treatment gaps. Objectives: To examine differential rates of oncologist evaluation and conditional treatment, by race, and to determine whether changing evaluation and treatment patterns reduced disparities. Research Design: Retrospective analysis of Surveillance Epidemiology and End Results-Medicare registry, enrollment, and claims data. Subjects: Patients age >65, white or African American race, diagnosed with American Joint Committee on Cancer stage III colon cancer between 1997 and 2002. N = 7176. Key Measures: Oncology specialty evaluation and management visit or chemotherapy claim; receipt of 5-fluorouracil based chemotherapy. Time periods are grouped into early (1997-1998), middle (1999-2000), and late (2001-2002). Results: Initial adjusted oncologist evaluation rates were higher for whites compared with African American patients (58.7% vs. 42.9%). but changes over time reduced the race gap substantially. We did not find significant race-time trends in treatment rates conditional on oncologist evaluation. Conclusions: Race disparities in medical oncologist evaluations diminished over time, possibly in response to increased provider supply or changing patient and provider attitudes, but there was no parallel reduction in disparities in conditional treatment rates. Projected decreases in oncologist supply suggest the need for further research on this relationship. Research on the role of supplemental medical insurance on disparities in treatment is needed, particularly as the cost of recommended adjuvant therapy increases.