title: The impact of perineural invasion on biochemical outcome after permanent prostate iodine-125 brachytherapy.
abstract: OBJECTIVE
  Perineural invasion (PNI) in prostate biopsies is associated with increased risk of higher Gleason score and worse pathologic stage. We report the influence of PNI in biochemical no evidence of disease (bNED) survival after (125)I prostate brachytherapy (BT).
  
  
  METHODS
  Pathology reports of 700 men with localized prostate cancer who underwent (125)I prostate BT in 1999-2008 were reviewed. The presence or absence of PNI in the biopsy was documented in 339 men. Clinical, treatment, and dosimetric parameters, along with PNI status, were evaluated for bNED survival, defined by "nadir+2" definition.
  
  
  RESULTS
  Of the 339 patients, 87% had favorable risk and 13% intermediate risk. PNI was present in 89 patients (26%). After a median followup of 32 months, there were five biochemical failures (4: +PNI and 1: -PNI), of which one was local failure (+PNI). Actuarial 5-year bNED survival for the entire group was 97.0% (92.9% for +PNI; 99.2% for -PNI). In univariate analysis age, pretreatment prostate-specific antigen, Gleason score 7, and intermediate risk group predicted for worse biochemical outcome, whereas the presence of PNI showed a trend toward significance (p=0.06). Some of the regression algorithms failed to converge because of low event rates.
  
  
  CONCLUSIONS
  We report excellent biochemical control in 339 men treated with (125)I prostate BT. The presence of PNI showed a trend toward significance in predicting 5-year bNED survival but did not impact on local control and should not influence the decision to recommend BT for localized prostate cancer.
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Alfonso Gómez-Iturriaga
authors.initials: AG
authors.lastname: Piña
authors.forename: Juanita Mary
authors.initials: JM
authors.lastname: Crook
authors.forename: Paul
authors.initials: P
authors.lastname: Kwan
authors.forename: Jette
authors.initials: J
authors.lastname: Borg
authors.forename: Clement
authors.initials: C
authors.lastname: Ma
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology / Q000517:prevention & control; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology* / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D017430:Prostate-Specific Antigen