Testicular ultrasonographic features predict future risk for bilateral testicular germ cell tumour: A long-term single centre follow-up study

Bilateral testicular germ cell tumours (B-GCT) are rare, with an incidence of 2-5%, and can be classified as synchronous (sB-GCT) or metachronous (mB-GCT). Our study aimed to identify clinical, biochemical, and radiological risk factors for mB-GCT in a cohort of patients with GCT at a single tertiary referral centre. This retrospective case-control study included patients with GCT referred to Policlinico Umberto I-Sapienza University of Rome, from 2005 to 2023. We evaluated clinical history, testicular ultrasound features, hormone levels, semen analysis, histological characteristics, staging, and treatments. mB-GCTs were compared with unilateral GCT patients with a follow-up longer than the median time-to-onset of the second tumour. Of 319 patients, 52 experienced B-GCT, with a median time-to-onset of the second tumour of 62 months (range: 8-229). The mB-GCT group showed higher gonadotropin levels (FSH 13.6mUI/mL vs. 7.4mUI/mL, p