Increased incidence of malignant melanoma and other rare cutaneous cancers in the setting of chronic lymphocytic leukemia.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), or non-Hodgkin lymphoma (NHL) are at increased risk for the development of skin malignancies.

OBJECTIVES: This study was conducted to estimate the incidences of rare skin malignancies in patients with CLL/SLL or NHL.

METHODS: Patients with a diagnosis of CLL/SLL or NHL recorded in the Surveillance, Epidemiology and End Results (SEER) database during 1992-2007 were identified. Diagnoses of specific skin malignancies were identified from SEER files.

RESULTS: During 1992-2007, a total of 128,674 patients with first diagnoses of CLL/SLL or NHL were recorded in SEER; 4743 were excluded because follow-up data were unavailable. Among the remaining 123,931 patients, 28,964 had CLL/SLL and 94,967 had NHL. Standardized incidence ratios (SIRs) for invasive malignant melanoma, Merkel cell carcinoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, Kaposi's sarcoma, and sebaceous carcinoma were 2.3, 8.2, 3.6, 2.5, 2.9, and 1.4, respectively, in CLL/SLL patients and 1.6, 3.2, 1.5, 1.3, 17.6, and 0.8, respectively, in NHL patients. When invasive melanoma was stratified by patient age and sex, the highest SIR (17.8) was found in men aged 0-49 years with CLL (P < 0.001).

CONCLUSIONS: Patients with CLL/SLL or NHL have a higher risk for the subsequent development of rare skin cancers. Given the more aggressive nature of these malignancies in this setting, regular monitoring for the development and prompt treatment of cutaneous malignancy is prudent in patients with NHL and particularly in patients with CLL. Regular use of sun protection may decrease the morbidity associated with skin cancer in this immunosuppressed population.