TAMOXIFEN FOR DISEASE-NEGATIVE BUT MCA-POSITIVE BREAST-CANCER PATIENTS

Increased levels of mucin-like carcinoma-associated antigen (MCA) in b reast cancer patients with no evidence of disease following the treatm ent of the primary disease created a dilemma of 'to treat' or 'wait an d see'. One might assume that early treatment of clinically undetectab le disease on the basis of an elevated serum level of a sensitive and reliable tumor marker, may improve the treatment results, and even pro long the patient's survival. 'Wait and see' on acceptance of the notio n that even early metastatic disease, still manifested only by uprisin g MCA levels, is incurable, and treatment should be kept in reserve fo r palliation of symptomatic disease. Sixty-one breast cancer patients with increasing MCA levels but without evidence of metastatic disease were randomized for tamoxifen 20 mg b.i.d. or to follow-up till relaps e. The results for a median follow-up period of one year were encourag ing. The non-treated patients experienced a significantly higher relap se rate (24.1%) than the tamoxifen-treated subjects (0%; p=0.012). The results for a median follow-up of 5 years were disappointing. The ove rall relapse rate was 22.2%. The relapse rate among the control patien ts was 25.8% while in the treatment arm it was 17.4% (p=0.46). The eve nt-free survival and the pattern of relapse were similar in both arms. Tamoxifen may therefore be reserved for overt metastases, and not was ted on asymptomatic subclinical disease. It seems that there is no yie ld in terms of event-free survival for MCA measurements in breast canc er patients during the 5-year follow-up period.