Response to hormonal therapy as a prognostic factor for metastatic breast cancer treated with combination chemotherapy.
One hundred thirty-six patients with metastatic carcinoma of the breast who received adequate trials of hormonal therapy were evaluated in order to determine the relationship of response to prior hormonal therapy and the results achieved with combination chemotherapy. Fifty-three patients had shown objective responses and 83 had failed to respond to the commonly used modes of endocrine therapy for carcinoma of the breast. Distribution of patient characteristics known to influence the response to chemotherapy and the type of chemotherapy used were similar for both groups. Of 53 hormone-responsive patients, 37 achieved either complete or partial responses for an overall response rate of 70%, not significantly different from the 67% response rate observed among patients unresponsive to hormonal therapy. The estimated medial duration of chemotherapy-induced response was 23 months for hormone-responsive patients, as compared with 13 months for the patients unresponsive to hormonal therapy (P < 0.01). Similarly, survival time was significantly prolonged among hormone-responsive patients as compared with the nonresponding patients, with estimated median survival times of 33 months and 16 months, respectively (P < 0.01). Central nervous system metastases developed in 16 (19%) of the 83 patients unresponsive to hormoinal therapy and this was significantly higher than the 6% rate (3 of 53) observed among the hormone-responsive patients (P = 0.05). Our data indicate that the nature of response to hormonal therapy in advanced breast cancer is an important prognostic factor for the results achieved with combination chemotherapy. An apparent increase in the incidence of central nervous system metastases among the hormone-unresponsive patients warrents further study.