Bilateral carcinoma of the breast.

A review of patients treated at the Peter MacCallum Clinic, Melbourne, between 1968 and 1973 inclusive, revealed 76 cases of primary carcinoma involving the opposite breast. Twenty-one of these occurred synchronously, when they were usually associated with elderly patients, a strong family history and an increased delay in presentation. The behaviour of these tumours was unremarkable, though the survival of the patients may have been less than those with single lesions, and in accord with the doubled risk of distant spread and local recurrence. Fifty-five patients with metachronous lesions did not present initally with features which would help to identify them as being prone to this double pathology. About 50% of the second carcinomas occurred within five years, but the remainder developed at intervals which were in several cases longer than 20 years. The patients did not present earlier on the second occasion, and several had advanced lesions. There was no evidence that the behaviour of the second carcinoma was influenced by immunological factors or patient susceptibility. Implications with regard to management are outlined, and the importance of long-term follow-up with regular examination is emphasized.