title: Pretreatment endorectal coil magnetic resonance imaging findings predict biochemical tumor control in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy.
abstract: OBJECTIVE
  To investigate the utility of endorectal coil magenetic resonance imaging (eMRI) in predicting biochemical relapse in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy.
  
  
  METHODS
  Between 2000 and 2008, 279 men with intermediate- or high-risk prostate cancer underwent eMRI of their prostate before receiving brachytherapy and supplemental intensity-modulated radiotherapy. Endorectal coil MRI was performed before treatment and retrospectively reviewed by two radiologists experienced in genitourinary MRI. Image-based variables, including tumor diameter, location, number of sextants involved, and the presence of extracapsular extension (ECE), were incorporated with other established clinical variables to predict biochemical control outcomes. The median follow-up was 49 months (range, 1-13 years).
  
  
  RESULTS
  The 5-year biochemical relapse-free survival for the cohort was 92%. Clinical findings predicting recurrence on univariate analysis included Gleason score (hazard ratio [HR] 3.6, p = 0.001), PSA (HR 1.04, p = 0.005), and National Comprehensive Cancer Network risk group (HR 4.1, p = 0.002). Clinical T stage and the use of androgen deprivation therapy were not correlated with biochemical failure. Imaging findings on univariate analysis associated with relapse included ECE on MRI (HR 3.79, p = 0.003), tumor size (HR 2.58, p = 0.04), and T stage (HR 1.71, p = 0.004). On multivariate analysis incorporating both clinical and imaging findings, only ECE on MRI and Gleason score were independent predictors of recurrence.
  
  
  CONCLUSIONS
  Pretreatment eMRI findings predict for biochemical recurrence in intermediate- and high-risk prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Gleason score and the presence of ECE on MRI were the only significant predictors of biochemical relapse in this group of patients.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Riaz
authors.forename: Asim
authors.initials: A
authors.lastname: Afaq
authors.forename: Oguz
authors.initials: O
authors.lastname: Akin
authors.forename: Xin
authors.initials: X
authors.lastname: Pei
authors.forename: Marisa A
authors.initials: MA
authors.lastname: Kollmeier
authors.forename: Brett
authors.initials: B
authors.lastname: Cox
authors.forename: Hedvig
authors.initials: H
authors.lastname: Hricak
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
mesh_terms: D000704:Analysis of Variance; D000726:Androgen Antagonists / Q000627:therapeutic use; D001918:Brachytherapy / Q000379:methods*; D003131:Combined Modality Therapy / Q000379:methods; D018572:Disease-Free Survival; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000097:blood; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology* / Q000532:radiotherapy*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D047368:Tumor Burden
chemical_list: D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen