A retrospective review of the Eastern Cooperative Oncology Group adjuvant chemotherapy studies EST 5177 and EST 6177 was performed in order to ascertain the first indicator of relapse in women with breast cancer and pathologically positive axillary lymph nodes. Of 856 evaluable patients, 208 have relapsed. In 175 patients who relapsed, the first indicator could be clearly identified: symptoms, 36%; patient self-examination, 18.3%; physical examination by the physician, 19.4%; abnormal blood chemistries, 12%; bone scans, 8%; chest x-rays, 5.1%; and mammograms, 1.1%. Although 74% of recurrences are therefore detected clinically, in a sizable proportion (26%), the ancillary tests were the earliest indicators of relapse. The manner of detection was not influenced by nodal, estrogen receptor (ER), or menopausal status. These results suggest that the follow-up schedule currently employed by ECOG appears reasonable.