ABSTRACT Aim Primary mediastinal germ cell tumors (PMGCTs), a rare subset of extragonadal GCTs, exhibit heterogeneous prognoses depending on histological subtype. Limited prospective clinical studies exist due to their rarity. This study analyzed therapeutic efficacy and prognostic factors for PMGCT patients. Methods We retrospectively analyzed PMGCT patients treated at Peking University Cancer Hospital (2009–2024). Progression‐free survival (PFS) and overall survival (OS) were evaluated using Kaplan‐Meier curves and log‐rank tests. Cox regression identified prognostic factors. Results Among 37 patients (the median age: 30; 35 males and two females), nine had seminomas, and 28 had non‐seminomas. All patients received chemotherapy, 21 received mediastinal radiotherapy, and 10 underwent surgery. The 1‐, 2‐, 3‐, and 5‐year OS rates were 92%, 81%, 73%, and 73%, respectively. The median PFS for the first‐line treatment (84% received bleomycin, etoposide, and cisplatin BEP regimen) was 9.1 months (95% confidence interval CI 4.6–13.5). Seminoma patients showed superior outcomes vs. non‐seminoma: PFS (not reached NR vs. 4.2 months, p < 0.001) and OS (NR vs. 29.5 months, p = 0.008). In non‐seminoma patients, demonstrated significant tumor reduction post‐first‐line therapy correlated with prolonged PFS ( p < 0.001). Cox regression indicated non‐seminoma patients who received mediastinal radiotherapy had significantly longer OS (hazard ratio HR 5.943, 95% CI 1.077–32.791; p = 0.041). Conclusions The BEP regimen, which was effective in testicular GCTs, demonstrates activity in PMGCTs. Seminomas showed superior therapeutic effect and survival compared to non‐seminomas. For non‐seminomas, the first‐line response might predict PFS, and mediastinal radiotherapy might provide additional survival benefits. These findings highlight histology‐driven prognostic stratification for PMGCTs and multimodal management for primary mediastinal non‐seminoma GCTs.
Wu et al. (Thu,) studied this question.