Survival Outcomes in Metastatic Germ Cell Tumors: A Multicenter Study from Turkey

Background/Objectives: Metastatic testicular germ cell tumor (mGCT) is a highly curable disease with first-line cisplatin-based combination chemotherapy. This study aims to evaluate the clinicopathological characteristics and survival outcomes of patients with metastatic testicular cancer in a nationwide multicenter cohort. Methods: This multicenter retrospective cohort study included 316 male patients diagnosed with mGCT who were treated with first-line cisplatin-based chemotherapy across 10 institutions in Turkey between 2011 and 2024. Clinical and pathological data, including International Germ Cell Cancer Collaborative Group (IGCCCG) risk classification, treatment details, and survival outcomes, were analyzed. Results: The median age of the cohort was 28 years, and 76.3% of patients were diagnosed with non-seminoma. According to IGCCCG risk stratification, 53.2% had good-risk, 25.3% intermediate-risk, and 21.5% poor-risk disease. Median follow-up was 38.4 months. Among patients with seminoma, the 5-year overall survival (OS) rate was 100% in the good-risk group and 87.5% in the intermediate-risk group. In patients with non-seminoma, 5-year OS rates were 96.6%, 86.9%, and 65.1% in the good-, intermediate-, and poor-risk groups, respectively. Among 125 patients who received salvage treatment, high-dose chemotherapy (HDCT) significantly improved survival in the International Prognostic Factors Study Group (IPFSG) very high-risk group (3-year OS: 55.0% vs. 16.3% with conventional-dose chemotherapy (CDCT), p = 0.007). Conclusions: This study provides the first large-scale nationwide dataset on mGCT outcomes in Turkey, demonstrating overall survival rates comparable to international cohorts. The findings emphasize the importance of a multidisciplinary approach, adherence to treatment guidelines, and optimal surgical interventions in improving patient outcomes.