Immunosuppressed patients are known to have an increased incidence of skin cancer. Patients with multiple myeloma (MM) show impaired immune function. In the past, because of poor survival, the incidence of specific secondary primary malignancies such as skin cancer among these patients was difficult to establish. With more effective MM therapies that have emerged in recent years, these patients are living markedly longer, and therefore, it becomes of increasing importance to determine whether their risk of developing other medical problems such as skin cancer is increased. We performed a retrospective cohort study of 205 myeloma patients and 193 age-, race-, and gender-matched control subjects to assess the incidence of skin cancers among patients with MM and determine the specific types of and risk factors for skin cancer. We found that there is an increased occurrence of skin cancer among patients with MM compared to control subjects (26.8% vs. 16.1% in controls; P = 0.009). Among specific types of skin cancer, the proportion of patients with squamous cell carcinoma (SCC) was higher than controls (P = 0.016). In addition to MM diagnosis, older age and Caucasian ethnicity were predictors of skin cancer of any type. Furthermore, older age was also a predictor of SCC.

e20044 Background: Multiple myeloma (MM) patients (pts) have shown a higher risk of developing other cancers, although the type, time course, and relationship to MM treatment of these cancers are less clear. In this study, we determined the risk of specific skin cancer (CA) types among MM patients and its relationship to onset of MM and treatment. Methods: MM pts and unrelated age, sex, and race-matched companions (controls) seen at a MM clinic were enrolled in a retrospective cohort study. Information regarding baseline characteristics of MM and history of skin CA was obtained from medical records. Overall skin CA prevalence and types were compared between groups; among MM patients, the occurrence of skin CA was analyzed relative to date of diagnosis and treatment regimens, with stratification according to treatment duration. Results: We enrolled 205 MM pts and 201 controls with 27.3% and 14.9% demonstrating skin CA, respectively (p < 0.001). Specific types of skin CA included 60 and 37 basal cell carcinomas (BCC), 50 and 17 squamous cell carcinomas (SCC), and 9 and 5 melanomas in the MM pts and controls, respectively. The standardized incidence ratios (SIR) were SCC: 2.88 (p< 0.001), BCC: 1.59 (p<0.001), and melanoma: 1.76 (p = 0.074). SCC SIR was elevated (p<0.001) across each yearly time point from 10 years prior to MM diagnosis through 10 years subsequent to MM diagnosis. BCC SIR was elevated (p <0.002) from 7 through 10 years following MM diagnosis. The SIR markedly increased over time following the diagnosis of MM for both SCC and BCC. Relative risk (RR) was determined for pts treated with bortezomib, immunomodulatory agents, alkylating agents, glucocorticoids, and anthracyclines. There was no significant increase in RR overall or for any specific type of skin CA in relationship to the type or duration of MM treatment. Conclusions: MM pts show an increased risk of skin CA (there was no increase in melanoma incidence), including SCC and BCC. SCC occurred before and following the diagnosis of MM whereas BCC followed the diagnosis of MM. The post-MM diagnosis increase in skin CA was not related to specific drugs used to treat MM.