title: Pretreatment nomogram that predicts 5-year probability of metastasis following three-dimensional conformal radiation therapy for localized prostate cancer.
abstract: OBJECTIVE
  There are several nomograms for the patient considering radiation therapy for clinically localized prostate cancer. Because of the questionable clinical implications of prostate-specific antigen (PSA) recurrence, its use as an end point has been criticized in several of these nomograms. The goal of this study was to create and to externally validate a nomogram for predicting the probability that a patient will develop metastasis within 5 years after three-dimensional conformal radiation therapy (CRT).
  
  
  METHODS
  We conducted a retrospective, nonrandomized analysis of 1,677 patients treated with three-dimensional CRT at Memorial Sloan-Kettering Cancer Center (MSKCC) from 1988 to 2000. Clinical parameters examined were pretreatment PSA level, clinical stage, and biopsy Gleason sum. Patients were followed until their deaths, and the time at which they developed metastasis was noted. A nomogram for predicting the 5-year probability of developing metastasis was constructed from the MSKCC cohort and validated using the Cleveland Clinic series of 1,626 patients.
  
  
  RESULTS
  After three-dimensional CRT, 159 patients developed metastasis. At 5 years, 11% of patients experienced metastasis by cumulative incidence analysis (95% CI, 9% to 13%). A nomogram constructed from the data gathered from these men showed an excellent ability to discriminate among patients in an external validation data set, as shown by a concordance index of 0.81.
  
  
  CONCLUSIONS
  A nomogram with reasonable accuracy and discrimination has been constructed and validated using an external data set to predict the probability that a patient will experience metastasis within 5 years after three-dimensional CRT.
authors.affiliation: Department of Urology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Box 27, New York, NY 10021, USA. kattanm@mskcc.org
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kattan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Kupelian
authors.forename: Daniel
authors.initials: D
authors.lastname: Cho
authors.forename: Peter T
authors.initials: PT
authors.lastname: Scardino
authors.forename: Zvi
authors.initials: Z
authors.lastname: Fuks
authors.forename: Steven A
authors.initials: SA
authors.lastname: Leibel
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D012372:ROC Curve; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D012306:Risk
chemical_list: D017430:Prostate-Specific Antigen