Evidence for an association between cutaneous melanoma and non-Hodgkin lymphoma

BACKGROUND. Over the past 2 decades both cutaneous melanoma (CM) and non-Hodgkin lymphoma (NHL) incidence rates have increased substantially. One approach to better understanding the etiologic basis for these increases is to examine the risk of NHL in CM survivors and the risk of CM in NHL survivors. METHODS. To explore the possible association between CM and NHL, the authors followed cohorts of CM and NHL patients registered through the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program between 1973 and 1996 and identified patients who developed CM after NHL and NHL after CM. The number of observed cases then were compared with the number of expected cases to see if CM survivors were at an increased risk of NI-IL or if NHL survivors were at an increased risk of CM. RESULTS. Between 1973 and 1996, 54,803 CM patients and 62,597 NHL patients who met the authors' inclusion criteria were identified through SEER. The authors found statistically significant elevated risks of NHL among CM survivors (standardized incidence ratio [SIR], 1.42; 95% confidence interval [CI], 1.23-1.63) and CM among NHL survivors (SIR, 1.75; 95% CI, 1.48-2.07). CONCLUSIONS. These results support an association between CM and NHL. Although detection bias and posttherapy effects may explain part of this association, shared genetic or etiologic factors, such as sunlight exposure, also may play a role. (C) 2001 American Cancer Society.