Delayed recovery of peripheral blood cell numbers after adjuvant cytotoxic chemotherapy for stage II breast cancer.

A study was made on the recovery of the bone marrow after adjuvant chemotherapy given to 30 post-mastectomy patients with stage II breast cancer treated with either melphalan or melphalan and methotrexate at 6-weekly intervals for 1 year. Counts of peripheral blood cells were made serially during treatment and then for a further 2 years after stopping chemotherapy. Mean counts for all cell types fell during chemotherapy and recovery was long-delayed. Thus 24 months after chemotherapy, mean counts for total leucocytes and platelets were significantly lower than mean pretreatment counts and counts for a normal female population, and the count for neutrophils was significantly lower than the count before treatment; after 24 months mean counts for lymphocytes were not significantly depressed. Melphalan was assumed to be the agent responsible. Slow haematological recovery after cessation of adjuvant chemotherapy with one particular regimen points to the need for including long-term post-chemotherapy observation of the bone marrow in the assessment of adjuvant chemotherapy programmes.