Evidence for an association between non-hodgkin lymphoma and melanoma

Purpose Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the United States, but the etiology of most cases remains obscure. We investigated the relation between family history of skin cancer and risk of NHL using data from the Selected Cancers Study. Methods Cases (n = 1008) were men ages 32 to 60 years diagnosed with NHL from 1984 to 1988 and identified from eight U.S. population-based cancer registries. Case diagnoses were confirmed on consensus after independent and blinded re-review of tissue specimens by a panel of three hematopathologists. Controls (n = 1782) were men identified by random-digit dialing and frequency-matched to cases by age and cancer registry. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (95% CI) adjusted for the design variables. Results Among men with a family history of melanoma, the odds ratio for overall risk of NHL was 3.3 (95% CI = 1.4, 7.5). The corresponding odds ratio among men with a family history of other skin cancer types was 0.8 (95% CI = 0.5, 1.1). Stratified analyses for NHL of the diffuse and follicular subtypes, which comprised more than 80% of cases, revealed odds ratios of 4.0 (95% CI = 1.5, 10.8) and 2.1 (95% CI = 0.6, 8.0) for risk of diffuse NHL and follicular NHL, respectively. Conclusion These data suggest that a family history of melanoma is associated with an increased risk of NHL, particularly diffuse NHL. In contrast, a family history of other skin cancer types did not appear to be associated with NHL risk.