Response to treatment and its influence on survival in metastatic breast cancer.

The clinical response to first systemic therapy of 381 patients with metastatic breast cancer was assessed; the influence of the category of this first response on eventual survival from diagnosis of first distant metastasis was analyzed. Survival from diagnosis of first distant metastasis was found to be similar whether the patient had a complete response, a partial response, or stable disease; only when progressive disease occurred with first systemic treatment was survival significantly shortened. This similarity in survival whatever the category of response from diagnosis of first distant metastases was found whether the patient received chemotherapy or hormone therapy as first systemic treatment, and whether the patient was premenopausal or postmenopausal; there was some suggestion on analysis of premenopausal patients treated with hormone therapy as first systemic therapy that a complete response conferred a survival advantage, but the numbers were small in this group. When complete responders to first systemic therapy as well as any other subsequent systemic therapy were analyzed for survival from diagnosis of first distant metastasis, again, no survival advantage could be found compared to the other response categories, but the complete response rate was low owing to the unselected nature of this group of study patients. It is concluded that the categories of complete, partial, or stable response to therapy have no great significance in terms of survival; the category of progressive disease to first systemic therapy is, however, associated with a shorter survival in all the analyses performed. We suggest that assessment of a treatment's worth should be based as much on the patient's subjective feeling of well-being as on the magnitude of the tumor response, since with currently available therapies, provided some form of response is obtained, the magnitude of the response does not appear to translate into any major survival advantage. This study points up the disparity between research-oriented criteria of response (survival, response rate, and its magnitude) and patient care criteria of response (survival and quality of life).