Incorporating age into International Germ Cell Consensus Classification (IGCCC): a time to move forward?

BACKGROUND: Older age is a poor prognostic indicator among patients with germ cell tumors. The current study evaluates an age-integrated international germ cell consensus classification (IGCCC) for advanced germ cell tumors.

METHODS: SEER database (2004-2014) was accessed through SEER*Stat program and both IGCCC and age-integrated IGCCC were calculated based on site of the primary, site of the metastasis and level of tumor markers. Overall survival analyses according to IGCCC and age-integrated IGCCC were conducted through Kaplan-Meier analysis.

RESULTS: Overall survival was compared according to IGCCC and age-integrated IGCCC for patients with seminoma and Non-seminomatous germ cell tumors (NSGCTs). P values were significant (P <0.001) for all scenarios. c-index for seminoma for IGCCC was 0.553; c-index for seminoma for age-integrated IGCCC was 0.664;c-index for NSGCTs for IGCCC was 0.729; and c-index for NSGCTs for age-integrated IGCCC was 0.738. A Cox-regression multivariate model of factors affecting cancer-specific survival (adjusted for race and surgical treatment) was conducted. All P values for pair wise comparisons (among different age-integrated IGCCC categories) were significant for both seminoma and NSGCTs (P<0.01).

CONCLUSION: Compared to traditional IGCCC, age-integrated IGCCC is more discriminatory and the new risk groups introduced within it are prognostically relevant.