In 141 postmenopausal node-positive patients with primary breast cancer, routine biochemical markers (alkaline phosphatase, gamma-glutamyl transpeptidase, carcinoembryonic antigen), and chest x-ray, in combination with history and clinical examination, have been performed at 3 monthly intervals for at least 2 years. Sixty one patients relapsed at a median time of 14 months. The recurrence was detected at routine follow-up in 40 (66%) patients. Of these 40 patients, 26 (65%) presented with symptoms, 11 (28%) were asymptomatic but were found to have relapsed on clinical examination, and only 3 (8%) had their relapse diagnosed on the basis of an abnormal chest x-ray. The remaining 21 patients presented early with symptoms. Therefore symptoms and clinical examination accounted for the detection of relapse in 58 of the 61 (95%) patients. Of the patients who had relapsed, 49% (30 of 61) had one or more abnormal markers/chest x-rays prior to relapse, rising to 79% (48 of 61) at the time of relapse. Of 80 patients with no evidence of recurrence, 36% (29) had no marker abnormality recorded, whereas in 64% (51) one or more abnormalities were found. These results suggest that history and examination are the important procedures in follow-up, and that abnormal markers are not always due to metastatic disease and may be misleading.