Effect on natural killer and antibody-dependent cellular cytotoxicity of adjuvant cytotoxic chemotherapy including melphalan in breast cancer

Natural killer (NK) cell activity and antibody-dependent (K) cell activity were studied sequentially in 30 patients with early node-positive breast cancer entered into an adjuvant chemotherapy trial. The drugs used were melphalan, and melphalan with methotrexate, given for 12 months. Estimations were made 3-monthly during chemotherapy, and then at 15 and 24 months to assess recovery. Mean values for NK-cell activity during chemotherapy were significantly lower than the mean pre-chemotherapy baseline value at all time-points from 3 to 15 months, but there was recovery by 24 months. Mean values for K-cell activity during chemotherapy did not appear to differ from the mean pre-chemotherapy value, but variability in individual values was high. Over a 4-year follow-up period, a comparison of 16 patients who did not develop recurrent breast cancer with 14 who did showed that NK-cell activity was significantly lower in the latter group 12 months after the start of chemotherapy.