Bone marrow biopsy during induction chemotherapy for acute myeloid leukaemia identifies only 50% of patients with resistant disease

A study was carried out to determine whether bone marrow biopsy performed on day 6 of induction therapy for acute myeloid leukaemia (AML) can identify those patients with resistant disease who would need an intensification of the first course of induction. Bone marrow biopsies were performed on day 6 of induction chemotherapy in 44 patients with AML treated with daunorubicin, cytosine arabinoside and thioguanine. Biopsies were assessed for blast count, trephine cellularity and leukaemic index. Discrimination between patients who went on to achieve remission and those with resistant disease was best achieved using the reduction in bone marrow cellularity from pretreatment marrow to day-6 marrow. However, this discriminator identified only 50% of the patients with resistant disease and included 13% of patients who achieved remission with the first course of chemotherapy. The other parameters of response were even less effective at discriminating between chemotherapy-resistant and chemotherapy-responsive disease.