Incidence and Clinical Pattern of Contralateral Synchronous and Metachronous Germ Cell Testicular Cancer.

Abstract Background Incidence of a second testicular tumor is higher in patients diagnosed with testicular cancer than in the general population. As incidence of unilateral germ cell cancer is increasing worldwide and most of these patients are cured, a growing number of patients at risk of developing a contralateral testis cancer is expected. Objective To analyze clinical and histological characteristics, as well as the absolute and cumulative incidence of a second testicular cancer in a cohort of 3,834 patients diagnosed with germ cell testicular cancer between I/1994 and I/2018 in 18 referral hospitals of the Spanish Germ Cell Cancer Group. Methods Patients were treated according to stage and year of diagnoses. Contralateral testis biopsy was not routinely performed, according to European Association of Urology rules. Follow-up of the contra lateral testis consists of a physical exam only and an annual optional testicular ultrasound for 10 years. Results Median age of the patients included was 32 years (18–82). With a median follow-up of 61 months (0–240), 67/3,834 patients (1.74%) were diagnosed with a second testicular tumor. The second testicular tumor was synchronic (diagnosed within 6 months of the first orchiectomy) in 19 patients, and metachronous in 48. Pathology of the second tumor was reported as a seminomatous testis tumor in 47 patients and a nonseminomatous cancer in 20. Cumulative incidence of contralateral testicular cancer was 2% at 5 years, and 4% (IC 95% 3%–5%) at 14 years. Younger age was a risk factor for developing a second testicular tumor (P = 0.006), whereas chemotherapy reduced the risk for a metachronous testicular cancer (P = 0.046). Within our cohort, 6 families with testicular cancer aggregation (more than 2 tumors in the same family) were identified. Conclusions Incidence of second testicular neoplasm in this cohort of 3,834 patients was similar to that which has been reported in other countries. Metachronous tumors and seminomas are more common. Follow-up of the contralateral testis is mandatory, as well as adequate information for patients to prevent a second neoplasm if feasible, and to detect and treat it as soon as possible.