title: Radical prostatectomy findings in patients predicted to have low-volume/low-grade prostate cancer diagnosed by extended-core biopsies: an analysis of volume and zonal distribution of tumour foci.
abstract: OBJECTIVE
  To measure total tumour volume (TTV) and dominant TV (DTV) in radical prostatectomy (RP) specimens from patients predicted to have low-volume, low-grade (LV/LG) prostate cancer, as this entity can be predicted from biopsy findings and prostate-specific antigen (PSA) level, but tumour under-sampling remains a challenge in active surveillance programmes.
  
  
  METHODS
  This was a retrospective study from an academic centre, of men with prostate cancer treated from 2000 to 2007, with a PSA level of <10 ng/mL and one core of cancer from an extended scheme showing either Gleason score (GS) 3 + 3 of <3.0 mm or 3 + 4 of <2.0 mm. All men had RP, and the TTV, DTV, tumour location, pathological GS and stage were measured.
  
  
  RESULTS
  Of 3055 RPs, 66 (2.1%) met the inclusion criteria. The core with cancer was from a sextant and alternative site in 26 (39%) and 40 (61%) patients, respectively. A pathological GS 3 + 3 or 3 + 4 was assigned to 94%, while 6% were GS > or = 4 + 3; all 66 tumours were organ-confined. The median (range) TTV and DTV were 0.15 (0.0008-5.06) and 0.14 (0.0008-5.04) mL, respectively. The median number of tumour foci was 3 (1-7), being unifocal in 17/66 (26%) and multifocal in 49/66 (74%). The transition zone was involved in 29% of unifocal and 71% of multifocal tumours. Of all 66 patients, the TTV was <0.5 mL in 47 (71%), and of 59 patients with biopsy GS 3 + 3, 33 (56%) had a TTV of <0.5 mL and pathological GS 3 + 3. Of 19 patients with a TTV of > or =0.5 mL, the median TTV was 1.06 (0.51-5.05) mL, with tumour foci of transition zone origin in 16 (84%). The study was limited by its retrospective design and small sample size.
  
  
  CONCLUSIONS
  Using conservative selection criteria for predicting LV/LG cancer, RP specimens showed organ-confined disease in all cases, upgrading to GS > or = 4 + 3 in 6%, and TTV <0.5 mL in 71% of cases. The transition zone is a common location of under-sampled disease.
authors.affiliation: Department of Urology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. johndavis@mdanderson.org
authors.forename: John W
authors.initials: JW
authors.lastname: Davis
authors.forename: Jeri
authors.initials: J
authors.lastname: Kim
authors.forename: John F
authors.initials: JF
authors.lastname: Ward
authors.forename: Xuemai
authors.initials: X
authors.lastname: Wang
authors.forename: Hiro
authors.initials: H
authors.lastname: Nakanishi
authors.forename: R Joseph
authors.initials: RJ
authors.lastname: Babaian
authors.forename: Patricia
authors.initials: P
authors.lastname: Troncoso
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology* / Q000601:surgery; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D047368:Tumor Burden