Long‐Term Clinical Outcomes of Advanced Germ Cell Tumors: Experience From 105 Patients Over 20 Years

OBJECTIVES: Limited data on metastatic germ cell tumors are available in Japan. We aimed to evaluate the long-term cancer-specific mortality of advanced germ cell tumors. METHODS: We present the clinical outcomes of 105 patients with mediastinal or metastatic germ cell tumors, including 33 seminoma and 72 non-seminoma, who received induction cisplatin-based chemotherapy at our hospital between September 2002 and February 2025. We evaluated the 5-year cancer-specific survival, pathologic findings of residual tumor resection, and risk factors for cancer death. RESULTS: The median follow-up period of all patients was 63 months (interquartile range: 26-120 months). The 5-year cancer-specific survival was 97% in patients with seminoma and 73% in patients with non-seminoma. Of 72 patients, 56 with non-seminoma received residual tumor resection after chemotherapy. In terms of pathologic findings, the proportions of viable cells, teratoma, and necrosis were 25%, 30%, and 45%, respectively. The 5-year cancer-specific survival was 90% in 47 patients with normalized tumor markers at the time of surgery and 28% in nine patients with non-normalized tumor markers. In multivariate analysis, non-pulmonary visceral metastasis was the most significant risk factor associated with cancer-related death. CONCLUSIONS: The treatment of patients with non-seminoma who present with non-pulmonary visceral metastases, including metastases to the liver, brain, bone, and other visceral sites, remains challenging. Although patient selection is crucial, a subset of patients with non-normalized tumor markers at the time of salvage surgery achieved long-term survival.