Physician-Driven Variation in Nonrecommended Services Among Older Adults Diagnosed With Cancer

IMPORTANCE: Interventions to address overuse of health care services may help reduce costs and improve care. Understanding physician-level variation and behavior patterns can inform such interventions. OBJECTIVE: To assess patterns of physician ordering of services that tend to be overused in the treatment of patients with cancer. We hypothesized that physicians exhibit consistent behavior. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of patients 66 years and older diagnosed with cancer between 2004 and 2011, using population-based Surveillance, Epidemiology, and End Results (SEER)-Medicare data to assess physician-level variation in 5 nonrecommended services. Services included imaging for staging and surveillance in low-risk disease, intensity-modulated radiation therapy (IMRT) after breast-conserving surgery, and extended fractionation schemes for palliation of bone metastases. MAIN OUTCOME AND MEASURES: To assess variation in service use between physicians, we used a random effects model and a logistic regression model with a lag variable to assess whether a physician’s use of a service for a prior patient predicts subsequent service use. RESULTS: Cohorts ranged from 3464 to 89 006 patients. The total proportion of patients receiving each service varied from 14% for imaging in staging early breast cancer to 41% in early prostate cancer. From the random effects analysis, we found significant unexplained variation in service use between physicians (P