Conditional survival of stage III non-seminoma testis cancer patients

Purpose: In many primaries other than non-seminoma testis cancer, the risk of death due to cancer decreases with increasing disease free interval duration after initial diagnosis and treatment. This effect is known as conditional survival and is relatively unexplored in stage III non-seminoma patients, where it may matter most in clinical decision-making. We examined the effect of disease-free interval duration on overall survival in stage III non-seminoma patients. Materials and Methods: Within the Surveillance, Epidemiology, and End Results Database (2004-2018), stage III non-seminoma patients were identified. Multivariable Cox regression analyses and conditional survival models were applied. Results: Of 2,092 surgically treated stage III non-seminoma patients, 385 (18%) exhibited good vs. 558 (27%) intermediate vs. 1,149 (55%) poor prognosis. In multivariable Cox regression models, poor prognosis group independently predicted overall mortality (HR 3.3, P < 0.001). In conditional survival analyses based on 36 months' disease-free interval duration, 5-year overall survival estimates were as follows: good prognosis patients 96 vs. 89% at initial diagnosis without accounting for disease-free interval duration (Delta.+7); intermediate prognosis patients 94 vs. 85% at initial diagnosis without accounting for disease-free interval duration (Delta.+9); poor prognosis patients 94 vs. 65% at initial diagnosis without accounting for disease-free interval duration (Delta.+29). Conclusions: Conditional survival estimates based on 36 months' disease-free interval duration provide a more accurate and more optimistic outlook for stage III non-seminoma patients than predictions defined at initial diagnosis, without accounting for disease-free interval duration. (c) 2023 Elsevier Inc. All rights reserved.