title: Perineural invasion and TRUS findings are complementary in predicting prostate cancer biology.
abstract: BACKGROUND
  Clinical variables with more accuracy to predict biologically insignificant prostate cancer are needed. We evaluated the combination of transrectal ultrasound-guided biopsy of the prostate (TRUSBx) pathologic and radiologic findings in their ability to predict the biologic potential of each prostate cancer.
  
  
  METHODS
  A total of 1043 consecutive patients who underwent TRUSBx were reviewed. Using pathologic criteria, patients with prostate cancer (n = 529) and those treated with radical prostatectomy (RP) (n = 147) were grouped as: "insignificant" (Gleason score ≤ 6, prostate-specific antigen (PSA) density ≤ 0.15 ng/ml, tumor in ≤ 50% of any single core, and < 33% positive cores) and "significant" prostate cancer. TRUSBx imaging and pathology results were compared with the RP specimen to identify factors predictive of "insignificant" prostate cancer.
  
  
  RESULTS
  TRUSBx pathology results demonstrated perineural invasion in 36.4% of "significant" versus 5.4% of "insignificant" prostate cancers (p < 0.01) and pathologic invasion of periprostatic tissue in 7% of significant versus 0% of insignificant prostate cancers (p < 0.01). TRUS findings concerning for neoplasia were associated with significant tumors (p < 0.01). Multivariable analysis demonstrated perineural invasion in the biopsy specimen (p = 0.03), PSA density (p = 0.02) and maximum tumor volume of any core (p = 0.02) were independently predictive of a significant prostate cancer.
  
  
  CONCLUSIONS
  TRUS findings concerning for measurable tumor and perineural invasion in TRUSBx specimens appear to be complementary to Epstein's pathologic criteria and should be considered to aid in the determination whether a prostate cancer is organ-confined and more likely to be biologically insignificant.
authors.affiliation: Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Martinez
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Williams
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Chin
authors.forename: Larry
authors.initials: L
authors.lastname: Stitt
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Izawa
mesh_terms: D000368:Aged; D001706:Biopsy; D018450:Disease Progression; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011467:Prostate / Q000294:innervation* / Q000473:pathology* / Q000601:surgery; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000601:surgery; D012007:Rectum; D012189:Retrospective Studies; D014463:Ultrasonography / Q000379:methods*