Thromboembolic disease in testicular germ cell tumors-real-world evidence of three Portuguese institutions.

Introduction: Testicular germ cell tumors (TGCTs) are highly curable malignancies with long-term overall survival (OS) exceeding 90%. Thromboembolic (TE) events are a relevant treatment-related complication, reported in approximately 10% of patients. This study aimed to evaluate the incidence, risk factors, and prognostic impact of TE in TGCT. Methods: We performed a retrospective multicenter cohort study including 136 post-pubertal male patients with histologically confirmed TGCT treated between 2007 and 2021 at three Portuguese centers. The primary endpoint was to characterize the population of TGCT patients with TE. Secondary endpoints included TE incidence and its impact on OS and progression-free survival (PFS). Identification of clinical, pathological, and treatment-related factors associated with increased TE risk was an exploratory endpoint. Results: Seven patients (5.1%) developed a TE event, all in advanced/recurrent disease (14.6% in this subgroup). No TE occurred in stage I patients, including those treated with adjuvant chemotherapy. Visceral metastases (pulmonary and extra-pulmonary) and poor IGCCCG prognosis were associated with TE ( Discussion: TE in TGCT occurred only in patients with advanced disease, was linked to tumor burden and CVC use, and was not predicted by current models. These findings highlight the need for TGCT-specific risk tools and prospective studies on risk-adapted prophylaxis.