Increased breast-cancer recurrence rate after adjuvant therapy with levamisole. A preliminary report. Executive Committee of the Danish Breast Cancer Cooperative Group.

After total mastectomy with partial axillary-lymph-node biopsy, patients with breast carcinomas with histologically positive lymph-nodes but without distant metastasis (N+, Mo) were allocated at random to receive either radiotherapy alone (384 patients) or radiotherapy plus levamisole 2.5 mg/kg/day for two consecutive days each week for 48 weeks (336 patients). At 1 year the levamisole-treated patients had a significantly higher recurrence rate than the radiotherapy-only group. They also had an unacceptably high incidence of side-effects, especially patients aged over 50. The frequency of levamisole-induced agranulocytosis was 3.6% and leucopenia 15-20%. These preliminary results suggest that adjuvant therapy with levamisole should not be used in patients with N+, Mo breast carcinoma.