CA 15-3 as a marker in the follow-up of patients with breast cancer

CA 15-3 was determined pre-operatively in 49 patients with stage III breast cancer and in 36 patients with stage IV breast cancer and the results were compared with the results in 64 healthy females. The upper reference limit of healthy females at 95 percent specificity was about 30 U/ml. In stage III cancer 50 percent of the patients have values of CA 15-3 above 30 U/ml, a value exceeded by 80 percent of the stage IV patients. In stage IV disease 30 percent of the patients have values above 100 U/ml being the 95 percentile of stage III patients.