Strategy for Evaluation of a New Antitumor Agent in the Treatment of Breast Cancer

Abstract

Carcinoma of the breast is the most sensitive of the common solid tumors to treatment with presently available chemotherapeutic agents. It therefore presents a dilemma to the experimental chemotherapist. On the one hand, a new drug is more likely to be active in this setting than in patients with colorectal or bronchogenic carcinoma; on the other hand, more old drugs with known low-level activity exist which might be tried first. The situation has, until recently, been further complicated by the activity of various hormonal manipulations in a fraction of patients with breast cancer. Fortunately, the minority of patients who will respond to such treatment may be further selected as being among those whose tumors contain high levels of estrogen receptor protein; thus, those with known absent or low levels of estrogen receptor protein need not undergo hormonal manipulation before chemotherapy.