Lack of association between renal cell carcinoma and non-Hodgkin's lymphoma

Objectives. To determine the incidence of non-Hodgkin's lymphoma (NHL) and renal cell carcinoma (RCC) after a diagnosis of the other malignancy. Methods. The 1973 to 1994 Surveillance, Epidemiology, and End Results (SEER ) data base was used to determine the age-, sex-, race-, and calendar year- specific incidence rates for each year for RCC and NHL. The expected number of second cancers for each sex, race, and follow-up period (less than 1, 1 to 5, 5 to 10, and 10 or more years) was obtained by multiplying these inc idence rates by the age-, sex-, race-, and calendar year-specific number of person-years at risk, with these products summed over the different age gr oups and calendar years. The standardized incidence ratio (SIR) was calcula ted (observed/expected number of second cancers), with statistical signific ance determined using the Poisson test. Results. From 1973 to 1994, 32,293 individuals in the SEER data base were d iagnosed with RCC and 63,997 with NHL. NHL was diagnosed after RCC in 67 ca ses versus 59.8 expected (SIR 1.12, P = 0.19) and RCC after NHL in 96 cases versus 56.1 expected (SIR 1.71, P <0.0001). Only white males and females h ad a significantly increased risk of RCC after NHL, which was limited to th e first year of follow-up. Excluding the first year of follow-up, NHL was d iagnosed after RCC in 54 cases versus 49.3 expected (SIR 1.10, P = 0.27) an d RCC after NHL in 54 cases versus 45.1 expected (SIR 1.20, P = 0.11). Conclusions. When the first year of follow-up is excluded, there is no incr eased risk of NHL after RCC or vice versa. UROLOGY 54: 28-33, 1999. (C) 199 9, Elsevier Science Inc.