An association between cutaneous melanoma and non-Hodgkin's lymphoma: pooled analysis of published data with a review.

BACKGROUND Several epidemiological studies have suggested an association between cutaneous melanoma and non-Hodgkin's lymphoma. METHODS We pooled the data from seven cohort studies and calculated the risk of secondary occurrence of cutaneous melanoma after non-Hodgkin's lymphoma, and of non-Hodgkin's lymphoma subsequent to the occurrence of cutaneous melanoma. RESULTS There were 137 612 patients with primary non-Hodgkin's lymphoma and 109 532 patients with primary cutaneous melanoma. We found a statistically significant increased risk of non-Hodgkin's lymphoma among cutaneous melanoma survivors [standardised incidence ratio (SIR) 2.01, 95% confidence interval (CI) 1.79-2.24] and cutaneous melanoma among non-Hodgkin's lymphoma survivors (SIR 1.41, 95% CI 1.26-1.58). CONCLUSION Our study confirmed an association between cutaneous melanoma and non-Hodgkin's lymphoma occurring in the same patient indicative of a need to examine further the role of the common risk factors.