Conditional Survival of Patients With Metastatic Testicular Germ Cell Tumors Treated With First-Line Curative Therapy

Abstract

Purpose: The International Germ Cell Cancer Collaborative Group (IGCCCG) criteria prognosticate survival outcomes in metastatic testicular germ cell tumor (MT-GCT), but how the initial risk changes over time for those who survived since curative treatment is unknown.

Patients and methods: We assessed patients eligible for first-line therapy for MT-GCT at five tertiary cancer centers from 1990 to 2012 for 2-year conditional overall survival (COS) and conditional disease-free survival (CDFS), defined as the probability of surviving, or surviving and being disease free, respectively, for an additional 2 years at a given time point since the initial diagnosis.

Results: For all patients (N = 942), 2-year COS increased from 92% (95% CI, 91% to 94%) at 0 months to 98% (95% CI, 97% to 99%), and 2-year CDFS increased from 83% (95% CI, 81% to 86%) at baseline to 98% (95% CI, 97% to 99%) at 24 months after diagnosis. Two-year COS improved by 2% (97% at 0 months, 99% at 24 months) in the IGCCCG favorable-risk group, by 5% (94% at 0 months, 99% at 24 months) in the intermediate-risk group, and by 22% (71% at 0 months to 93% at 24 months) in the poor-risk group. Two-year CDFS improved significantly at 12 months for each risk group (favorable, 91% baseline v 95% at 12 months; intermediate, 84% v 95%; poor, 55% v 85%). Baseline IGCCCG risk stratification was not associated with long-term COS or CDFS for patients who survived to greater than 2 years post therapy. No significant differences in COS and CDFS were noted between seminoma and nonseminoma; patients ≥ 40 years old had inferior 2-year COS from 0 to 12 months, but no differences were noted at 18 months.

Conclusion: Our data suggest that the concept of conditional survival applies to patients with MT-GCT treated with curative therapy. Patients with MT-GCT who survived and remained disease free more than 2 years after the diagnosis had an excellent chance of staying alive and disease free in additional subsequent years, regardless of the initial IGCCCG risk stratification.