Abstract
BACKGROUND: Our purpose was to identify physicians' individual characteristics, attitudes, and organizational contextual factors associated with higher enrollment of patients in cancer clinical trials among physician participants in the National Cancer Institute's Community Clinical Oncology Program (CCOP). We hypothesized that physicians' individual characteristics, such as age, medical specialty, tenure, CCOP organizational factors (i.e. policies and procedures to encourage enrollment), and attitudes toward participating in CCOP would directly determine enrollment. We also hypothesized that physicians' characteristics and CCOP organizational factors would influence physicians' attitudes toward participating in CCOP, which in turn would predict enrollment. METHODS: We evaluated enrollment in National Cancer Institute-sponsored cancer clinical trials in 2011 among 481 physician participants using Structural Equation Modeling. The data sources include CCOP Annual Progress Reports, two surveys of CCOP administrators and physician participants, and the American Medical Association Masterfile. RESULTS: Physicians with more positive attitudes toward participating in CCOP enrolled more patients than physicians with less positive attitudes. In addition, physicians who practiced in CCOPs that had more supportive policies and practices in place to encourage enrollment (i.e. offered trainings, provided support to screen and enroll patients, gave incentives to enroll patients, instituted minimum accrual expectations) also significantly enrolled more patients. Physician status as CCOP Principal Investigator had a positive direct effect on enrollment, while physician age and non-oncology medical specialty had negative direct effects on enrollment. Neither physicians' characteristics nor CCOP organizational factors indirectly influenced enrollment through an effect on physician attitudes. CONCLUSION: We examined whether individual physicians' characteristics and attitudes, as well as CCOP organizational factors, influenced patient enrollment in cancer clinical trials among CCOP physicians. Physician attitudes and CCOP organizational factors had positive direct effects, but not indirect effects, on physician enrollment of patients. Our results could be used to develop physician-directed strategies aimed at increasing involvement in clinical research. For example, administrators may want to ensure physicians have access to support staff to help screen and enroll patients or institute minimum accrual expectations. Our results also highlight the importance of recruiting physicians for volunteer clinical research programs whose attitudes and values align with programmatic goals. Given that physician involvement is a key determinant of patient enrollment in clinical trials, these interventions could expand the overall number of patients involved in cancer research. These strategies will be increasingly important as the CCOP network continues to evolve.