title: The role of the maximum involvement of biopsy core in predicting outcome for patients treated with dose-escalated radiation therapy for prostate cancer.
abstract: OBJECTIVE
  To evaluate the influence of the maximum involvement of biopsy core (MIBC) on outcome for prostate cancer patients treated with dose-escalated external beam radiotherapy (EBRT).
  
  
  METHODS
  The outcomes of 590 men with localized prostate cancer treated with EBRT (≥75 Gy) at a single institution were retrospectively analyzed. The influence of MIBC on freedom from biochemical failure (FFBF), freedom from metastasis (FFM), cause-specific survival (CSS), and overall survival (OS) was compared to other surrogates for biopsy tumor volume, including the percentage of positive biopsy cores (PPC) and the total percentage of cancer volume (PCV).
  
  
  RESULTS
  MIBC correlated with PSA, T-stage, Gleason score, NCCN risk group, PPC, PCV, and treatment related factors. On univariate analysis, MIBC was prognostic for all endpoints except OS; with greatest impact in those with Gleason scores of 8-10. However, on multivariate analysis, MIBC was only prognostic for FFBF (hazard ratio [HR] 1.9, p = 0.008), but not for FFM (p = 0.19), CSS (p = 0.16), and OS (p = 0.99).
  
  
  CONCLUSIONS
  In patients undergoing dose-escalated EBRT, MIBC had the greatest influence in those with Gleason scores of 8-10 but provided no additional prognostic data as compared to PPC and PCV, which remain the preferable prognostic variables in this patient population.
authors.affiliation: The Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI, USA.
authors.forename: Jure
authors.initials: J
authors.lastname: Murgic
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Stenmark
authors.forename: Schuyler
authors.initials: S
authors.lastname: Halverson
authors.forename: Kevin
authors.initials: K
authors.lastname: Blas
authors.forename: Felix Y
authors.initials: FY
authors.lastname: Feng
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hamstra
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy; D000368:Aged; D001706:Biopsy; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D015996:Survival Rate; D047368:Tumor Burden