Accrual to the Breast Cancer Prevention Trial by participating Community Clinical Oncology Programs: a panel data analysis.

In 1992 patient accrual to the National Cancer Institute-sponsored Breast Cancer Prevention Trial was initiated in the United States and Canada. The Trial will involve 16,000 women who are evaluated to be at high risk of developing breast cancer. Nearly 250 health care organizations are participating in the Trial, including over 40 Community Clinical Oncology Program (CCOP) organizations, which are a component of the NCI's national clinical trials program. A previous NCI-funded evaluation conducted by the University of North Carolina showed the CCOP program to be an effective means of transferring the latest cancer technology, particularly cancer treatments, to the community setting. This paper describes a study designed to evaluate the performance of CCOP organizations in the Breast Cancer Prevention Trial. Using data from the first fifteen months of the Trial, the ability of CCOPs to accrue women is assessed using panel data estimation techniques. An attempt is made to predict accrual by structural, process, and environmental characteristics of participating CCOPs. Factors predictive of accrual include month in which accrual occurred and the extent of competition for trial participants in the CCOP service area. The hypothesized model explains slightly over 19 percent of the variation in accrual performance. The analysis demonstrates the utility of a panel data approach to modeling the dynamics of CCOP participation in a chemoprevention clinical trial.