Patients with tumors which appear localized at diagnosis frequently develop metastases after primary definitive therapy. This suggests that occult (microscopic) dissemination of tumor has occurred prior to presentation. This is optimally treated early with chemotherapy after primary definitive treatment. The rationale for this approach is based on cytokinetic studies: micrometastases are more sensitive to anticancer agents thatn larger primary tumors from which they were derived and treatment administered when the tumor burden is at its nadir avoids the necessity to escalate doses and affect host tolerance. The application of these concepts to clinical practice has resulted in significant increases in survivals. Investigations to facilitate early detection of clinical metastases and the integrated use of multidisciplinary treatment for eradication of metastases are outlined.