title: Prognostic value of modeled PSA clearance on biochemical relapse free survival after radical prostatectomy.
abstract: OBJECTIVE
  Using population kinetic approach, we modeled PSA decline equations in patients with prostate cancer after radical prostatectomy (RP). We looked for relationships between early PSA decrease profile, characterized by PSA clearance (CL(PSA)) or half-life (HL(PSA)), and the 2-year biochemical relapse free survival (bRFS).
  
  
  METHODS
  We performed a retrospective study on 55 patients treated with RP and with at least 2 PSA measurements in the post-operative month. A population kinetic model was investigated with NONMEM. The prognostic factors regarding bRFS were assessed using univariate and multivariate analyses.
  
  
  RESULTS
  The best model describing the PSA post-operative decrease was bi-compartmental and fit patient data well. Median CL(PSA) was 0.034 (terciles were 0.023 and 0.048). The significant prognostic factors associated with a better bRFS with univariate analysis were lower CL(PSA) terciles (2-year bRFS = 100% vs. 85.1% vs. 66.7% if CL(PSA) < 0.023, 0.023 <or= CL(PSA) < 0.048 or CL(PSA) >or= 0.0480, P = 0.006) as well as initial PSA < 7 ng/ml, pT2 stage (vs. pT3), pN0 (vs. pN1) and low main Gleason score (3/5 vs. 4/5). Among these factors, CL(PSA) was the only independent prognostic factor with multivariate analysis regarding bRFS (HR = 0.92, 95%CI = [0.86-0.98], P = 0.0088).
  
  
  CONCLUSIONS
  CL(PSA) determined with 4 PSA concentrations in the first month following the RP may predict the biochemical relapse risk of prostate cancer patients, thus enabling early identification of high-risk patients requiring adjuvant treatment. A prospective validation of these results is required.
authors.affiliation: Université de Lyon, Lyon, France. benoit.you@chu-lyon.fr
authors.forename: Benoit
authors.initials: B
authors.lastname: You
authors.forename: Pascal
authors.initials: P
authors.lastname: Girard
authors.forename: Philippe
authors.initials: P
authors.lastname: Paparel
authors.forename: Gilles
authors.initials: G
authors.lastname: Freyer
authors.forename: Alain
authors.initials: A
authors.lastname: Ruffion
authors.forename: Anne
authors.initials: A
authors.lastname: Charrié
authors.forename: Emilie
authors.initials: E
authors.lastname: Hénin
authors.forename: Michel
authors.initials: M
authors.lastname: Tod
authors.forename: Paul
authors.initials: P
authors.lastname: Perrin
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011184:Postoperative Period; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies
chemical_list: D017430:Prostate-Specific Antigen