A Suggested Prognostic Reclassification of Intermediate and Poor-Risk Nonseminomatous Germ Cell Tumors

The International Germ Cell Cancer Collaborative Group (IGCCCG) classification has been used since 1997 to allocate metastatic germ cell tumors (GCTs), but its applicability needs an update. We aimed to revisit the outcomes of intermediate and poor risk nonseminomatous GCTs (NSGCTs).

Individual patient-level data from the databases of 2 institutions were collected. Outcomes of consecutive patients who received first-line chemotherapy from 1990 to 2014 were used. The Kaplan-Meier method was used to estimate relapse-free (RFS) and overall survival (OS). Cox regression analyses were used to evaluate potential prognostic factors of RFS and OS univariably. Forward stepwise selection was used to construct a multivariable model. A risk factor (RF) model was then constructed and compared with IGCCCG classification using the concordance statistics (CS).

A total of 647 patients were identified. Four RFs for OS in the multivariable model were identified: primary mediastinal NSGCT (P < .001), brain metastases (P < .001), lung metastases (P = .016), and age at the time of diagnosis (P = .003). CS were improved on the basis of the number of RF (0, 1, 2, and 3 or 4) compared with IGCCCG (RFS: 0.63 vs. 0.58; OS: 0.65 vs. 0.59). For intermediate risk, there were no differences between 3 (n = 25) and 4 cycles of cisplatin, etoposide, and bleomycin (BEP; n = 159) or BEP × 3 + etoposide and cisplatin (EP) × 1 (n = 31) for RFS (P = .35) and OS (P = .061).

An improved risk stratification was obtained for intermediate and poor risk GCTs. Our reclassification system might provide an aid for a reclassification attempt of all GCT patients. Our prognostic model might be offered to clinicians to improve their ability to assess patient prognosis, enhance stratification, and inform patients.