Swiss adjuvant trials in women with node-negative breast cancer. OSAKO.

Women with node-negative breast cancer have a 30% chance of relapse 5 years after mastectomy. If it is possible to prevent or defer recurrent disease with adjuvant systemic therapy, node-negative patients, with their low tumor burden, should theoretically benefit most from such treatment. In 1974 we started a randomized adjuvant trial in eastern Switzerland, using a subjectively less toxic regimen [chlorambucil, methotrexate, and fluorouracil (LMF)]. Two hundred fifty-four patients were randomly assigned after standardized modified radical mastectomy to observation only or to treatment with oral LMF for 6 months followed by BCG skin scarifications monthly for up to 2 years. While we find no significant statistical difference between the control group and the treated group in terms of relapse-free survival, there is a strong and consistent trend toward prolongation of overall survival within the treated group.