Increased incidence of non-melanomatous skin cancer in patients with chronic lymphocytic leukemia, an 11-year case-control study

Abstract

19554 Background: Chronic Lymphocytic Leukemia (CLL) is a disease of B lymphocytes that affects immune tolerance and surveillance. Patients with CLL have an increased risk of basal and squamous cell skin carcinomas, which tend to be aggressive. We report the incidence of non-melanomatous (NM) in a >80% Caucasian cohort of patients with CLL and compared them to normal controls who reside in Southern California. Methods: A retrospective review was conducted of all patients in the Naval Medical Center San Diego tumor registry with CLL diagnosed between Jan 1, 1995 and Dec 31, 2005. The electronic records of 74 CLL patients and 100 control patients from the internal medicine clinic were assessed for skin biopsies performed at our institution revealing NM skin malignancies. Results: Within our CLL population, the average age at diagnosis was 72.2 years. 34% (25/74) had NM skin cancer with an incidence of 11,457 NM skin cancers per 100,000 person-years. The average number of malignant lesions was 3.7 per patient with one patient receiving 17 biopsies. 27% (7/25) of CLL patients with NM skin cancer had only squamous cell carcinoma and 23% (6/25) had only basal cell carcinoma. 42% (11/25) of patients had both squamous and basal cell cancers and one had a Merkel cell carcinoma. In the control population, the average age at diagnosis was 76.4 years. 16% (16/100) had NM skin malignancies with an incidence of 5,333 NM skin cancers per 100,000 person-years. The average number of malignant lesions was 3.7 per patient with one patient receiving 28 biopsies. 63% (10/16) had basal cell carcinomas, only 25% (4/16) had squamous cell carcinomas and 13% (2/16) had both types of cancer. Conclusions: Patients with CLL are at increased risk of developing NM skin cancers, especially squamous cell carcinomas. Patients with CLL have a 2.1 times higher risk of developing NM skin cancer than our control population, who had an incredibly high rate of skin cancer compared to prior publications. CLL patients should be closely screened for cutaneous malignancies in order to excise them before they cause further morbidity. Increased surveillance is especially prudent for elderly patients with fair skin types who have been exposed to a large amount of UV-light. No significant financial relationships to disclose.