Temporal change in risk of metachronous contralateral renal cell carcinoma: influence of tumor characteristics and demographic factors.

PURPOSE

To determine the relative risk (RR) of developing a metachronous contralateral renal tumor after an initial diagnosis of renal cell carcinoma (RCC), with stratification by renal tumor characteristics, demographic factors, and follow-up duration, in order to develop an improved risk-based surveillance strategy.

PATIENTS AND METHODS

The 1973 to 1997 Surveillance, Epidemiology, and End Results database was used to determine the observed and expected number of metachronous contralateral renal tumors developing after an initial diagnosis of RCC.

RESULTS

A total of 43,483 patients had a first diagnosis of RCC. Contralateral RCC developed subsequently in 155 (0.4%) of 40,049 patients with follow-up who had no synchronous diagnosis of RCC, with 10.81 expected cases (RR, 14.3; 95% CI, 12.2 to 16.8). The respective RRs (and 95% CIs) for contralateral RCC for white men and women were 16.0 (11.1 to 22.3) and 13.7 (7.7 to 22.6) at less than 2 years, 8.8 (5.0 to 14.3) and 10.5 (5.0 to 19.3) at 2 to 5 years, 13.5 (8.1 to 21.0) and 5.1 (1.4 to 13.2) at 5 to 10 years, and 13.0 (6.2 to 23.9) and 13.7 (5.0 to 29.9) at > or = 10 years, respectively. The RRs were significantly higher in black compared with white men for the first 5 years, with the RRs (and 95% CIs) in the former group of 95.3 (58.2 to 146.7) at less than 2 years and 41.9 (16.8 to 86.3) at 2 to 5 years.

CONCLUSION

The incidence of metachronous contralateral RCC is stable on long-term follow-up, suggesting that surveillance of the contralateral kidney should remain rigorous on extended follow-up. Black men are at a significantly higher risk of developing contralateral RCC in the first 5 years of follow-up.