Bilateral germ cell testicular tumors in New Zealand: experience in Auckland and Christchurch 1978-1994.

PURPOSE: The incidence of germ cell testicular tumors (GCTTs) is increasing world wide, and with effective treatment, the majority of patients are being cured. Thus, the clinical and social impact of a second testicular tumor is becoming more important. The frequency, cumulative risk, and relative risk of developing a second testicular cancer in New Zealand have been documented and compared with other reports. PATIENTS AND METHODS: The records of 741 men presenting with germ cell testicular cancer in Auckland and Christchurch between 1978 and 1994 have been reviewed, and these data have been compared with data from other published studies. Cumulative risk was assessed by the Kaplan-Meier method. RESULTS: Over 2% of the study population developed a second germ cell testicular cancer. The cumulative risk was 5.2% over 15 years. The relative risk of developing a contralateral testicular tumor is 27.5 times higher than age-matched New Zealand peers. These results match the only comparable report in the literature. Five of the 16 bilateral tumors (31%) were synchronous, which is a higher incidence than in any other reported series. There was no concordance of histology in the first and second tumors. Prior exposure to cisplatin combination chemotherapy did not prevent the development of a second tumor. CONCLUSION: Men who are cured of a germ cell testicular cancer have a greatly increased risk of developing a second testicular cancer. Such patients should be informed of this risk and ideally kept under long-term surveillance.