title: Prognostic significance of perineural invasion on biochemical progression-free survival after prostate brachytherapy.
abstract: OBJECTIVE
  To evaluate the influence of perineural invasion (PNI) in the biopsy specimen on biochemical progression-free survival in hormone-naive patients with prostate cancer undergoing brachytherapy.
  
  
  METHODS
  A total of 512 consecutive hormone-naive patients (173 low risk, 212 intermediate risk, and 127 high risk) underwent brachytherapy for clinical Stage T1b-T2cNxM0 (2002 American Joint Committee on Cancer staging system) prostate cancer. No patient underwent seminal vesicle or pathologic lymph node staging. All patients had undergone brachytherapy at least 3 years before analysis. The median follow-up was 5.3 years. Biochemical progression-free survival was defined by a prostate-specific antigen (PSA) cutpoint of 0.4 ng/mL or less after nadir and by the American Society for Therapeutic Radiology and Oncology consensus definition. PNI was defined as carcinoma tracking along, or around, a nerve within the perineural space.
  
  
  RESULTS
  PNI was documented in 133 patients (26.0%). For both biochemical progression-free definitions, 94.0% and 94.9% of patients with and without PNI, respectively, remained free of biochemical progression. The median time to failure in patients with and without PNI was 17.2 and 17.9 months, respectively. For the biochemically disease-free cohort, the median posttreatment PSA level was less than 0.1 ng/mL. On univariate Cox regression analysis, the pretreatment PSA level, percentage of positive biopsies, prostate volume, and Gleason score predicted for biochemical outcome. PNI did not approach statistical significance (P = 0.671). On multivariate analysis, only pretreatment PSA (P < 0.001) and the percentage of positive biopsies (P < 0.001) maintained statistical significance.
  
  
  CONCLUSIONS
  In hormone-naive brachytherapy patients implanted with generous periprostatic treatment margins, the presence of PNI in the biopsy specimen did not adversely affect 8-year biochemical progression-free survival.
authors.affiliation: Schiffler Cancer Center, USA. gmerrick@wheelinghospital.com
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Merrick
authors.forename: Wayne M
authors.initials: WM
authors.lastname: Butler
authors.forename: Kent E
authors.initials: KE
authors.lastname: Wallner
authors.forename: Robert W
authors.initials: RW
authors.lastname: Galbreath
authors.forename: Zachariah A
authors.initials: ZA
authors.lastname: Allen
authors.forename: Edward
authors.initials: E
authors.lastname: Adamovich
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy; D018450:Disease Progression; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D011467:Prostate / Q000294:innervation; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D015996:Survival Rate