We have implemented a consultant-extender system that enables community physicians, in cooperation with regional specialists, to deliver adjuvant chemotherapy to patients with node-positive breast cancer. The system employs computer-generated care protocol forms that indicate the data to be collected and the drug dose(s), with the appropriate rules for their administration. This continuous process of monitoring and modifying therapy assures protocol compliance and facilitates quality of care assessment. Seventy-three physicians throughout Alabama delivered appropriate chemotherapy at nearly 97% of 2612 visits by 195 patients. Disease-free intervals of 149 of those patients treated in a prospective clinical trial are indistinguishable from those of comparable patients treated largely within academic centers. This system provides a mechanism for decentralizing speciality care, incorporating community physicians into clinical trials, and improving continuing medical education techniques.