Conditional Overall Survival Research Articles

Conditional Survival Analysis of Patients With Locally Advanced Laryngeal Cancer: Construction of a Dynamic Risk Model and Clinical Nomogram

Conditional survival (CS), the survival beyond a pre-defined time interval, can identify periods of higher mortality risk for patients with locally advanced laryngeal cancer who face treatment-related toxicity and comorbidities related to alcohol and smoking in the survivorship setting. Using Weibull regression modeling, we analyzed retrospectively abstracted data from 638 records of patients who received radiation to identify prognostic factors for overall survival (OS) and recurrence free survival (RFS) for the first 3 years of survival and for OS conditional upon 3 years of survival. The CS was iteratively calculated, stratifying on variables that were statistically significant on multivariate regression. Predictive nomograms were generated. The median total follow up time was 175 months. The 3- and 6- year actuarial overall survival (OS) was 68% (95% confidence interval [CI] 65–72%) and 49% (CI 45–53%). The 3-year conditional overall survival (COS) at 3 years was 72% (CI 65–74%). Black patients had worse COS over time. Nodal disease was significantly associated with recurrence, but after 3 years, the 3-year conditional RFS converged for all nodal groups. In conclusion, the CS analysis in this patient cohort identified subgroups and time intervals that may represent opportunities for intervention.

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

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. 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. 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. 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.