Clinical trials. A family physician's perspective. Primary care specialists diagnose and manage a wide variety of problems. Cancer is one relatively small part of the practice of these clinicians. Patients with newly diagnosed cancer usually are referred to surgical specialists. Primary care physicians often determine future events after surgical care. Oncologists may or may not be consulted depending on tumor type and past experiences of the physician, patient, and patient's family. Many primary care physicians think that chemotherapy regimens given empirically have little if any scientific evidence to support their use. Side effects of cancer treatment regimens often cause suffering and profoundly effect quality of life. There is a lack of communication between oncologists and primary care physicians. Dialogue between oncologists and primary care doctors may help solve communication problems. Clinical trials help determine which treatments are effective. Many clinical trials are conducted at the community hospital level. Most primary care physicians support clinical trials once they know about them. Education activities should be directed at promoting patient referral for participation in clinical trials. 