Incidence of second and secondary malignancies in patients with CLL: A single institution experience.

Abstract

6568 Background: Patients with chronic lymphocytic leukemia (CLL) have a higher incidence of second malignancies than the general population with one study showing the risk at 2.2 times the general popualtion. The increased incidence is thought to be due to immunosupression which results in decreased cell surveillance and proliferation of malignant cells. Our study aims to present the rate of second malignancies by cancer type in patients with CLL at our institution. Methods: The Moffitt Cancer Center Total Cancer Care (TCC) database was used to identify patients who had a diagnosis of CLL between January 1993-December 2009. Individual charts were reviewed to confirm the diagnosis of CLL, collect demographic data, and to assess for the presence of a second malignancy under an IRB approved protocol. A second malignancy was defined as another malignancy or transformation of CLL reported in the medical record. Second malignancy data was placed in three categories; skin cancers, solid tumor malignancy, and hematologic malignancy. Results: 546 CLL patients were included in the study. Median age was 62.5 years. 84 (43%) were Stage 0 and 62 (32%) were Stage 1 RAI at diagnosis indicating earlier disease. 266 (49%) patients had a second or secondary malignancy. A total of 304 cancers were identified. 14% of patients had more than one malignancy. Melanoma was identified in 44 (16.5%) patients and non-melanoma skin cancer was identified in 54 (20%). Lung cancer was identified as the most frequent solid tumor malignancy with 36 (13.5%) cases, followed by prostate (35), breast (21), colorectal (15), and bladder (14). 10 patients had a Richter’s transformation of their CLL. 26 patients developed either myelodysplastic syndrome or acute myelogenous leukemia. Conclusions: Second malignancies are frequent in CLL patients. Immunosupression, increased UV light exposure, longer life expectancy in low risk CLL, and tertiary cancer center referral bias are likely reasons for these increased rates. Further research is needed to identify the precise mechanism which cause patients with CLL to have higher rates of second malignancies and to identify if there is an increased risk of a specific type of malignancy in patients with CLL.