To provide improved evidence for treatment recommendations, this study analysed real-world data on the characteristics, treatment and prognosis of primary extragonadal germ cell tumours (EGCTs), a very rare cancer entity that shares histological features with testicular GCTs (TGCT).
This retrospective study analysed data from 34 patients with mediastinal or retroperitoneal EGCTs treated at a high-volume centre between 2015 and 2025. Probability of overall survival (OS) and relapse-free survival (RFS) was assessed using Kaplan-Meier curves.
A primary retroperitoneal and primary mediastinal GCT was diagnosed in 23 (68%) and 11 (32%) patients, respectively. Median patient age was 41.1 years, and 62% were non-seminomatous in origin. Thirty-three (97%) patients received chemotherapy according to the IGCCCG prognostic group, and 15 (44%) underwent surgical intervention (4 primary RPLND, 8 post-chemotherapy RPLND, 3 secondary orchiectomy). Thirteen patients (44.9%) who completed chemotherapy experienced a relapse after a median of 0.79 years, and six of them died. In patients with primary mediastinal seminoma, 3-year RFS and OS were 100% as compared to 71% 3-year OS in patients with primary retroperitoneal non-seminoma and 46% 3-year RFS in patients with primary mediastinal non-seminoma.
The prognosis for primary mediastinal seminoma appears favourable, while non-seminomatous EGCT shows poorer outcomes. Additionally, primary retroperitoneal seminomas demonstrate promising survival rates, whereas primary retroperitoneal non-seminomas demonstrate the lowest OS rates.
BJUI compass. 2026 Apr 16*** epublish ***
Marc Kidess, Marcus Hentrich, Franz Aschl, Oksana Chernova, Sebastian Beckstein, Peter Bojko, Sebastian Schulz, Julia Neitz, Julian Hermans, Yannic Volz, Benedikt Ebner, Patrick Keller, Maria Apfelbeck, Julian Marcon, Philipp Weinhold, Christian G Stief, Lennert Eismann, Michael Chaloupka
Department of Urology LMU University Hospital of Munich Munich Germany., Department of Medicine III Red Cross Hospital Munich Munich Germany., School of Computation, Information and Technology Technical University of Munich Munich Germany.