Retrospective analysis of second malignancies in patients with multiple myeloma.

Abstract

8090 Background: Recent data from patients with multiple myeloma (MM) enrolled in randomized clinical trials have shown an increased incidence of second malignancies after treatment with lenalidomide, but the prevalence of second malignancies in the overall MM population is uncertain. Methods: We retrospectively analyzed the medical records of 320 consecutive MM patients followed at the Penn State Hershey Cancer Institute between 2006 and 2010. We excluded from the analysis basocellular and squamocellular carcinomas of the skin. Results: Forty-three patients (13%) were found to have second malignancies, and 5 of them had a third cancer. One pt had 4 cancers. They included cancers of the prostate (8 pts), breast (8), MDS/leukemia (6), colon/rectum (5), melanoma (5), lung (4), uterus (4), bladder (3), kidneys (2), pancreas (2), testicle (1), myeloproliferative disorders (1), and sarcoma (1). Of 50 cancers, 36 (72%) developed before the diagnosis of MM, at a median of 65 months (range, 1-372), and 14 after that, at a median of 37 months (range, 3-104). Lenalidomide was used in 239 (75%) patients, and in 9 of 14 cases of post-MM second malignancies. Conclusions: Second malignancies usually develop before the diagnosis of MM, i.e., MM is the second malignancy for the majority of patients. The use of lenalidomide could not be indicated as a possible carcinogenic factor for the majority of MM patients with second malignancies.