Perioperative adjuvant chemotherapy in breast cancer. The Scandinavian Adjuvant Chemotherapy Study 1

In a randomized study of operable primary breast cancer patients initiated January 1965, 507 patients received one single course with cyclophosphamide 5 mg/kg/day for six days, first dose given immediately after mastectomy. The 519 control patients received no adjuvant chemotherapy. In other respects both groups were treated equally. Median follow-up time is 17.1 years. In terms of relapse-free percentage, the difference between the groups after 20 years is 13.5% in favour of the cyclophosphamide group. The difference is statistically highly significant. This benefit is observed in node positive as well as in node negative patients, and over as well as under 50 years. The immediate side effects of the cyclophosphamide course have been very moderate. No late complications have been observed. In a parallel randomized study with 110 patients where the same course was given 2-4 weeks after mastectomy, no benefit could be observed.