Conditional survival (CS) represents the probability that a cancer patient will survive some additional number of years, given that the patient has already survived for a certain period of time. CS estimates, therefore, serve as better measures of survival probability compared to standard estimates as they incorporate patient survivorship. Stage-specific CS has not been widely investigated in the context of renal cell carcinoma (RCC) after nephrectomy. We aimed to examine this phenomenon.
We analyzed retrospective data on a population-based cohort of 87,225 surgically-treated RCC patients extracted from the Surveillance, Epidemiology, and End Results database (2004-2015) and on a similar validation cohort of 1,642 patients from our institution (1995-2015). 5-year cancer-specific CS estimates stratified by stage were obtained using the Kaplan-Meier method. Multivariable Cox regression analyses were performed to evaluate the possible variation in risk of cancer-specific mortality by stage at nephrectomy and with increasing postoperative survivorship.
5-year cancer-specific survival rates at time of nephrectomy for stage I, II, III, and IV patients in the population-based cohort were 97.4%, 89.9%, 77.9%, and 26.7%, respectively. Improvement in 5-year CS was mainly observed in surviving patients with advanced-stage disease; given 1, 2, 3, 4, and 5 years of survivorship after nephrectomy, the subsequent 5-year cancer-specific survival rates were, respectively, 79.3% (+1.8% increase over previous survival probability), 81.3% (+2.5%), 83.3% (+2.5%), 84.3% (+1.2%), and 85.1% (+1.0%) for stage III, and 34.6% (+29.6%), 42.5% (+22.8%), 49.0% (+15.3%), 55.7% (+13.7%), and 58.6% (+5.2%) for stage IV. A similar trend was established in the validation cohort. Findings were confirmed upon multivariable analyses.
CS after nephrectomy for RCC varies dramatically by stage of disease. Gains in CS over time occur primarily among patients with advanced-stage disease. Stage-specific CS estimates can help urologists better plan postoperative surveillance for RCC patients.
Urologic oncology. 2019 Sep 12 [Epub ahead of print]
Joseph G Cheaib, Hiten D Patel, Michael H Johnson, Michael A Gorin, Elliott R Haut, Joseph K Canner, Mohamad E Allaf, Phillip M Pierorazio
Department of Urology, The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD. Electronic address: ., Department of Urology, The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD., Division of Acute Care Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD; The Armstrong Institute for Patient Safety and Quality, Johns Hopkins Medicine, Baltimore, MD; Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., Center for Surgical Trials and Outcomes Research, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.