The key role of time in predicting progression-free survival in patients with renal cell carcinoma treated with partial or radical nephrectomy: Conditional survival analysis

IntroductionIn surgically treated patients with renal cell carcinoma (RCC), the progression-free survival (PFS) rate may significantly change according to the progression-free postoperative period. To test this hypothesis, we set to evaluate the conditional PFS rate in surgically treated patients with RCC.MethodsWe evaluated 1,454 patients with RCC, surgically treated between 1987 and 2010, at a single institution. Cumulative survival estimates were used to generate conditional PFS rates. Separate Cox regression models were fitted to predict clinical-progression risk in patients who were progression free from 1 to 10 years after surgery.ResultsDuring the immediate postoperative period, the 5-year PFS rate was 88%, and it increased to 92%, 94%, and 97% in patients who remained progression free at, respectively, 1, 5, and 10 years after surgery. At multivariable analyses, where patients with stage I disease were considered as a reference, the highest clinical-progression risk was observed at the eighth postoperative year in patients with stage II disease (hazard ratio [HR]: 2.9) and during the immediate postoperative period in patients with stage III to IV disease (HR: 5.5). In comparison with patients with grade I disease, the highest clinical-progression risk was observed at the fourth (as well as eighth) postoperative year in patients with grade II disease (HR: 5.7), sixth postoperative year in patients with grade III disease (HR: 7.2), and during the immediate postoperative period in patients with grade IV disease (HR: 8.5).ConclusionsThe postoperative progression-free period has an important effect on the subsequent clinical-progression risk. This aspect should be considered along with tumor characteristics to plan the most cost-effective follow-up scheme for surgically treated patients with RCC.