Breast Cancer: An Update

Breast cancer comprises approximately 13 .9% of all cases of malignancy in both sexes and 19% in women, in whom it is the commonest form of cancer . 1 The American Cancer Society estimates that 11 0,000 women developed breast cancer in 1 981 , and some 3 7, 1 00 deaths from the disease occurred. ~ The fiveyear survival rate has been improving over the past 40 years as shown in Table 11 , but patients remain in risk of recurrence indefinitely, and survival for ten years is generally accepted as the minimal time period necessary to establish the validity of new therapies. Data from the first study of the National Surgical Adjuvant Breast and Bowel Project (NSABP) are shown in Table 2 and indicate that the majority of women with breast cancer ultimately succump to the di$ease.3 Thus, although only 1 0% of cases present with metastatic disease (an additional 5% predictably have very rapid progression : inflammatory carcinoma, extensive local or regional disease), over half of those undergoing mastectomy will develop recurrence within ten years. The identification of women with either adverse or favorable prognostic features modifies these figures considerably. Among the important favorable variables are : attainment of menopausal status for at least five years ; in-