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

Introduction: In 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. Methods: We 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. Results: During 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). Conclusions: The 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.