title: Twelve-month prostate-specific antigen values and perineural invasion as strong independent prognostic variables of long-term biochemical outcome after prostate seed brachytherapy.
abstract: OBJECTIVE
  To determine whether post-treatment prostate-specific antigen (ptPSA) values at 12 months and other clinical parameters predict long-term PSA relapse-free survival (PRFS) following prostate seed brachytherapy.
  
  
  METHODS
  Records of 204 hormone-naïve patients with localized adenocarcinoma of the prostate treated at St. Mary's Regional Medical Center in Reno, NV, and at Carson Tahoe Regional Medical Center in Carson City, NV, between 1998 and 2003, using I-125 or Pd-103 seed brachytherapy, were retrospectively analyzed. Treatment planning was done using a preplanned, modified peripheral loading technique. A total of 185 of 204 patients had PSA records at 12 months after implant. Variables included were age, initial pretreatment PSA, Gleason score, T stage, National Comprehensive Cancer Network (NCCN) risk group (RG), perineural invasion (PNI), external beam boost, dose, and ptPSA levels at 12 months with cutpoints at ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml.
  
  
  RESULTS
  Median follow-up was 80 months, and median age was 69 years. The numbers of patients stratified by NCCN low, intermediate, and high RG were 110:65:10, respectively. Monotherapy and boost prescription doses were 145 Gy and 110 Gy for I-125, and 125 Gy and 100 Gy for Pd-103 seeds, respectively. The median dose (D90) was 95.4% of the prescribed dose. The 5-year PRFS at the 12-months ptPSA levels of ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml were 98.5%, 85.7%, 61.5%, and 22.2%, respectively. The 10-year PRFS at the 12-months ptPSA levels of ≤1 and 1.01 to 2.00 ng/ml were 90.5% and 85.7%, respectively. In multivariate analysis, both ptPSA and PNI were significant independent predictors of PRFS. Hazard ratios (HR) for ptPSA levels at ≤1, 1.01 to 2.00, 2.01 to 3.00, and >3.00 ng/ml at 12 months were 1, 4.96, 27.57, and 65.10, respectively. PNI had an HR of 6.1 (p=0.009).
  
  
  CONCLUSIONS
  Presence of PNI and ptPSA values at 12 months are strong prognostic variables for long-term PRFS after definitive prostate brachytherapy seed implantation.
authors.affiliation: Department of Radiation Oncology, California Pacific Medical Center, San Francisco, California 94115, USA. billyding888@gmail.com
authors.forename: William
authors.initials: W
authors.lastname: Ding
authors.forename: John
authors.initials: J
authors.lastname: Lee
authors.forename: David
authors.initials: D
authors.lastname: Chamberlain
authors.forename: James
authors.initials: J
authors.lastname: Cunningham
authors.forename: Lixi
authors.initials: L
authors.lastname: Yang
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tay
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001918:Brachytherapy / Q000379:methods*; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000097:blood; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D010165:Palladium / Q000627:therapeutic use; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D011868:Radioisotopes / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D010165:Palladium; D017430:Prostate-Specific Antigen