title: 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.
abstract: BACKGROUND
  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.
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy. Electronic address: firas.abdollah@gmail.com.
authors.forename: Firas
authors.initials: F
authors.lastname: Abdollah
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Nazareno
authors.initials: N
authors.lastname: Suardi
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Capitanio
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Rayan
authors.initials: R
authors.lastname: Matloob
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Fossati
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Castiglione
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Di Trapani
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Di Trapani
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Russo
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Carenzi
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Patrizio
authors.initials: P
authors.lastname: Rigatti
authors.affiliation: Department of Urology, URI-Urological Research Institute, San Raffaele Hospital, University Vita-Salute, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Bertini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000379:methods*; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000706:statistics & numerical data; D011184:Postoperative Period; D011379:Prognosis; D016016:Proportional Hazards Models; D013997:Time Factors; D055815:Young Adult
keywords: Disease-free survival; Postoperative period; Renal cell carcinoma/surgery; Survival analysis; Treatment outcome