Investigating the Incidence of Contralateral Metachronous Testicular Cancer Following Radical Orchidectomy

Abstract

Background: Testicular cancer is the most common malignancy in males aged 15 - 40 years. Although germ cell tumors (GCTs) account for the majority of cases, metachronous contralateral testicular cancer is rare. Objectives: This study aimed to evaluate the incidence of metachronous contralateral testicular cancer in patients without known risk factors, to assess the necessity of routine contralateral testicular biopsy. Methods: This historical cohort study included 220 patients under 40 years old with unilateral testicular GCT diagnosed before March 2019 at Shahid Modares Hospital, Tehran, Iran. Patients with cryptorchidism, family history of testicular cancer, testicular atrophy, or immunodeficiency were excluded. Finally, 95 patients completed at least a 5-year follow-up. Data were collected from medical records and patient interviews. Results: The mean age at diagnosis was 30.5 years. Seminoma was the most common pathology (50.5%). Right-sided tumors were more frequent (56.8%). After a minimum follow-up of 5 years, only one (1.05%) patient developed metachronous contralateral testicular cancer, occurring 5.5 years after the initial diagnosis. Conclusions: The incidence of metachronous contralateral testicular cancer in patients without risk factors was low (1.05%). Therefore, in strictly low-risk patients (no cryptorchidism, family history, or atrophy), routine contralateral testicular biopsy may not be necessary given the low incidence. Further studies with larger sample sizes are recommended to establish definitive guidelines.