Accelerated growth of skin carcinoma following fludarabine therapy for chronic lymphocytic leukemia.

We present four patients with chronic lymphocytic leukemia treated with fludarabine, who developed aggressive skin cancer after years of quiescence, a short time after institution of treatment. Their leukemias responded well to therapy with fludarabine with initial treatment as well as relapse. Three patients had recurrence with basal cell carcinomas with multiple, rapidly growing tumors and one had recurrence of both basal and squamous cancers and eventually died of metastatic squamous cell carcinoma. Fludarabine induces prolonged period of lymphopenia, affecting especially the T cell population, which is crucial in the defense against skin cancers. There appears to be a direct association between fludarabine and the flare up of skin cancers in these patients, possibly analogous to the increased incidence of these malignancies in patients on chronic cyclosporine immunosuppression.