Therapeutic oophorectomy in metastatic breast cancer.

One hundred five patients undergoing therapeutic oophorectomy for metastatic breast cancer (n = 105) from 1975 to 1985 were reviewed. There were 54 responders (51%) to oophorectomy, with a median duration of response of 16 months (range, 3 to 129 months). Thirty of 42 (71%) estrogen receptor (ER)-positive patients responded to oophorectomy versus five of 24 (21%) ER-negative patients (P less than 0.001). Of the 39 patients with unknown ER status, 19 (49%) responded to oophorectomy. Osseous, soft tissue, and pulmonary metastases responded at similar rates. Of the 16 patients who had received adjuvant chemotherapy, there were five responders (31%) to oophorectomy. Second-line endocrine therapy was effective in 29 of 53 (55%) patients. Fifteen of 28 (54%) ER-positive patients responded to second-line endocrine therapy while two of six (33%) ER-negative patients responded. Twenty-three of 37 (62%) oophorectomy responders responded to second-line endocrine therapy versus six of 16 (38) nonresponders. Oophorectomy appears to be a valuable palliative treatment for metastatic breast cancer. ER-positive patients have the best chance of responding to this therapy. However, ER-negative patients have a reduced but definite chance of responding with a good duration of response. Response to further endocrine treatments is predicted by response to oophorectomy and to a lesser degree by ER status.