Abstract 5644: Second cancer risks among lymphoma survivors in the SEER-Medicare linked dataset
Authors: Morton Lindsay M. , Curtis Rochelle E. , Engels Eric A. , Caporaso Neil , Tucker Margaret A. , Warren Joan L. , Fraumeni Joseph F. 
Published: February 2011

Background. Second cancers are a leading cause of morbidity and mortality among cancer survivors. Previous studies have shown increased second cancer risks after non-Hodgkin lymphoma and chronic lymphocytic leukemia (CLL); however, no earlier investigation has quantified differences in second cancer risk by lymphoma subtype, and little is known about the second cancer etiologies.

Methods. We evaluated second cancer risks compared with the general population among 62,841 two-month survivors of the most common lymphoma subtypes [CLL/small lymphocytic lymphoma (SLL), follicular lymphoma (FL), and diffuse large B-cell lymphoma (DLBCL)] diagnosed in 13 SEER registry areas during 1992-2006. To investigate specific risk factors for second cancers following lymphoma, we then identified 51,909 patients in the SEER-Medicare linked dataset who were diagnosed with lymphoma at age 66 years or older during 1992-2005. Risk factor data were obtained from Medicare claims for treatment and medical conditions. Patients with second primary invasive cancers were ascertained in the corresponding SEER registry files. Risk factors were modeled using multivariate Cox proportional hazards regression for each lymphoma subtype, adjusting for potential confounders.

Results. Lung cancer was the most common second malignancy and occurred in excess compared with the general population for survivors of CLL/SLL and FL but not for survivors of DLBCL [CLL/SLL: standardized incidence ratio (SIR)=1.53, 95% confidence interval (CI) 1.39-1.68; FL: SIR=1.34, 95%CI 1.15-1.55; DLBCL: SIR= 1.03, 95%CI 0.89-1.19)]. A similar pattern was observed for cutaneous melanoma (CLL/SLL: SIR=2.08, 95%CI 1.73-2.48; FL: SIR=1.47, 95%CI 1.09-1.94; DLBCL: SIR=1.16, 95%CI 0.85-1.54). Acute non-lymphocytic leukemia risks were significantly elevated after all three major lymphoma subtypes, with higher risks for FL and DLBCL than for CLL/SLL (CLL/SLL: SIR=1.58, 95%CI 1.03-2.32; FL: SIR=5.32, 95%CI 3.85-7.17; DLBCL: SIR=4.63, 95%CI 3.43-6.12). In the SEER-Medicare linked dataset, 5,002 patients with a second primary invasive cancer after lymphoma were identified, including 744 patients with lung cancer, 198 with melanoma, and 88 with acute non-lymphocytic leukemia. Results will be presented for second cancer risk factors of interest obtained from the Medicare database, including radiotherapy, specific chemotherapeutic agents, history of emphysema and chronic obstructive pulmonary disease, and specific infections (e.g., bronchitis, pneumonia, influenza).

Discussion. Identification of risk factors for second cancers after lymphoma will provide valuable information for lymphoma survivors and their physicians as well as advancing our understanding of carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5644.