Bone marrow morphologic changes after combination chemotherapy including VP-16

Bone marrow aspirates and biopsy specimens were examined from seven patients with small cell lung cancer. All patients had received recent combination chemotherapy including VP-16. No correlation between marrow biopsy cellularity and hematologic toxicity could be established. However, an unusual combination of morphologic changes was seen. This included an initial rapid increase in the M:E ratio, interference with cell division, and eventual cell death. There was little evidence of mitotic arrest or megaloblastosis. These changes are consistent with the known mechanism of action of VP-16, the only agent given to all patients. The small sample size and the unknown contributions of the other cytotoxic agents administered allow only limited conclusions.