Patient and physician decision styles and breast cancer chemotherapy use in older women: Cancer and Leukemia Group B protocol 369901.

PURPOSE Physician and patient decision styles may influence breast cancer care for patients ≥ 65 years ("older") because there is uncertainty about chemotherapy benefits in this group. We evaluate associations between decision-making styles and actual treatment. METHODS Data were collected from women treated outside of clinical trials for newly diagnosed stage I to III breast cancer (83% response) from January 2004 through April 2011 in 75 cooperative group sites. Physicians completed a one-time mailed survey (91% response), and clinical data were abstracted from charts. Patient decision style was measured on a five-point scale. Oncologists' preference for prescribing chemotherapy was based on standardized vignettes. Regression and multiple imputation were used to assess associations between chemotherapy and other variables. Results There were 1,174 women seen by 212 oncologists; 43% of women received chemotherapy. One-third of women preferred to make their own treatment decision. Patient and physician decision styles were independently associated with chemotherapy. Women who preferred less physician input had lower odds of chemotherapy than women who preferred more input (odds ratio [OR] = 0.79 per 1-point change; 95% CI, 0.65 to 0.97; P = .02) after considering covariates. Patients whose oncologists had a high chemotherapy preference had higher odds of receiving chemotherapy (OR = 2.65; 95% CI, 1.80 to 3.89; P < .001) than those who saw oncologists with a low preference. CONCLUSION Physicians' and older patients' decision styles are each associated with breast cancer chemotherapy use. It will be important to re-evaluate the impact of decision styles when there is greater empirical evidence about the benefits and risks of chemotherapy in older patients.