Introduction:

The International Germ Cell Cancer Collaborative Group (IGCCCG) risk groups for non-seminomatous germ cell tumors (NSGCT) help predict prognosis and inform management for patients. Age and the presence of lung metastasis are additional factors that impact progression-free survival and may also improve risk stratification models. However, these variables require validation with assessment of cancer-specific (CSS) and overall survival (OS).The International Germ Cell Cancer Collaborative Group (IGCCCG) risk groups for non-seminomatous germ cell tumors (NSGCT) help predict prognosis and inform management for patients. Age and the presence of lung metastasis are additional factors that impact progression-free survival and may also improve risk stratification models. However, these variables require validation with assessment of cancer-specific (CSS) and overall survival (OS).

Methods:

From the Surveillance, Epidemiology, and End Results (SEER) program, we classified NSGCT patients (2004–2016) as good, intermediate, or poor risk based on current IGCCCG criteria. Cox proportional hazard models and Kaplan-Meier curves assessed the impact of age, lung metastasis, and other visceral metastatic sites on survival and model accuracy.

Results:

Among all advanced NSGCT patients (N=1,394), increasing age (CSS HR 1.04 (95%CI: 1.02-1.05), p<0.001) and lung metastasis (CSS HR 2.62 (95%CI: 1.67-4.12), p<0.001) improved model accuracy and portended poorer CSS and OS.  Lung metastasis (CSS HR 4.57 (95%CI: 1.18-17.77), p=0.028) impacted outcomes among good risk patients, demonstrating worse survival for Stage IIIA compared to Stage IIC NSGCT (Table 1). Among poor risk patients, lung metastasis did not influence CSS or OS after accounting for other visceral metastases; patients with multiple non-pulmonary visceral disease sites had the poorest outcomes (CSS HR 2.40 (95%CI: 1.30-4.46), p=0.005) (Table 2).

Conclusion:

While traditional IGCCCG criteria currently do not include age or lung metastasis for advanced NSGCT, our results validate their impact on risk stratification and model discrimination for CSS and OS. Lung metastasis led to worse survival among good risk patients, while multiple non-pulmonary visceral metastases drove inferior outcomes among poor risk patients.

Funding: This work is supported by a grant from the National Cancer Institute (P30CA072720).