title: Prostate-specific antigen kinetics after I125-brachytherapy for prostate adenocarcinoma.
abstract: OBJECTIVE
  To investigate a potential correlation between the achievement of a cut-off of nadir PSA (nPSA) after brachytherapy (BRT) with biochemical Disease-Free Survival (bDFS) and to define the rate of post-BRT PSA bounces.
  
  
  METHODS
  Retrospective analysis was carried out in 105 consecutive patients affected with early-stage prostate adenocarcinoma who underwent (125)I BRT. Only patients with a minimum follow-up ≥24 months were included. Biochemical DFS was chosen as primary endpoint.
  
  
  RESULTS
  At a median follow-up of 51.2 months, 3- and 5-year bDFS were 96.8 and 91.2%, respectively. Median time to biochemical failure (BF) was 54 months. By Kaplan-Meier analysis, patients achieving nPSA ≤ 0.35 ng/mL had significantly higher bDFS (3- and 5-year bDFS: 100 and 98.5 % vs. 83.3 and 66.7 %, respectively; p = 0.001). Bounce PSA occurred in 28.6% of patients, at a median time of 21.5 months. No BFs were observed in the bounce group. Achieving a nPSA ≤ 0.35 ng/mL was the only factor independently associated with long-term bDFS on both univariate (p = 0.000) and multivariate analysis (HR 3.82; p = 0.003).
  
  
  CONCLUSIONS
  Patients attaining a nPSA ≤ 0.35 ng/mL are significantly more likely to experience long-term freedom-from-biochemical failure. Bounce PSA occurs in approximately 30% of patients. Time to onset of PSA increase seems the most reliable feature to distinguish bounce from failure. Tailored follow-up strategies are needed for patients at higher risk of recurrence, and caution is advised in interpreting an early increase in PSA levels in the first 24-30 months after BRT.
authors.affiliation: Radiation Oncology, Department of Medical and Surgical Sciences, University of Torino, Via Genova 3, 10126, Turin, Italy. alessia.guarneri@virgilio.it
authors.forename: Alessia
authors.initials: A
authors.lastname: Guarneri
authors.forename: Angela
authors.initials: A
authors.lastname: Botticella
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ragona
authors.forename: Andrea Riccardo
authors.initials: AR
authors.lastname: Filippi
authors.forename: Fernando
authors.initials: F
authors.lastname: Munoz
authors.forename: Giovanni
authors.initials: G
authors.lastname: Casetta
authors.forename: Paolo
authors.initials: P
authors.lastname: Gontero
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tizzani
authors.forename: Umberto
authors.initials: U
authors.lastname: Ricardi
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000532:radiotherapy*; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001918:Brachytherapy; D018572:Disease-Free Survival; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D007610:Kallikreins / Q000378:metabolism*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen