Endorectal magnetic resonance imaging for predicting pathologic T3 disease in Gleason score 7 prostate cancer: implications for prostate brachytherapy

Brachytherapy. May-Jun 2013;12(3):204-9. doi: 10.1016/j.brachy.2011.12.013. Epub 2012 Jun 5.

Abstract

Purpose: To determine the ability of endorectal magnetic resonance imaging (erMRI) and other pretreatment factors to predict the presence and extent of extraprostatic extension (EPE) in men with Gleason score (GS) 7 prostate cancer.

Methods and materials: We included patients with clinical stage T1c-T2c, GS=7 (3+4 or 4+3), and prostate-specific antigen (PSA) <10ng/mL who underwent pre-prostatectomy erMRI. We compared pathologic EPE findings with pretreatment factors.

Results: One hundred seventy-one men were eligible for inclusion. Pretreatment characteristics were: median age=60 years (42-76); median PSA 4.9ng/mL (0.4-9.9); GS 3+4=61%; T1c=51%; T2a=25%; T2b=21%; T2c=3%; ≥50% positive cores=46%; EPE-positive (EPE+) erMRI=28%. Thirty-three percent had pathologic EPE. Increasing T-stage (p<0.0001) and EPE+ erMRI (p<0.0001) were significant predictors of pathologic EPE, whereas GS (4+3 vs. 3+4) (p=0.14), percentage of positive core biopsies (p=0.15), and pretreatment PSA (p=0.41) were not. Median EPE distance was 1.75mm (range, <1-15mm). The rates of EPE >5mm and EPE >3mm were 11% and 15%, respectively. The odds ratios for erMRI detection of any EPE and of EPE >5mm were 3.06 and 3.75, respectively.

Conclusions: T-stage and EPE+ erMRI predict pathologic EPE in men with GS 7 prostate cancer. The ability of erMRI to detect EPE increases with increasing EPE distance. These findings may be useful in patient selection for prostate brachytherapy monotherapy.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Brachytherapy / methods*
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Neoplasm Grading / methods*
  • Prostate / pathology*
  • Prostatic Neoplasms / diagnosis*
  • Prostatic Neoplasms / radiotherapy
  • Rectum
  • Reproducibility of Results
  • Retrospective Studies