title: Greatest percentage of involved core length and the risk of death from prostate cancer in men with highest Gleason score ≥ 7.
abstract: BACKGROUND
  Men with highest GS ≥ 7 and a differing, lower GS core (ComboGS) have decreased PC-specific mortality (PCSM) risk after RT or RT and androgen deprivation therapy (ADT). Whether the greatest percentage of involved core length (GPC) modulates this risk is unknown.
  
  
  METHODS
  Men with GS ≥ 7 PC (n = 333) consecutively treated between December 1989 and July 2000 using RT (n = 268; 80%) or RT and 6 months of ADT (n = 65; 20%) comprised the study cohort. The GPC was calculated using biopsy core and tumor lengths. We used competing risks regression to assess whether increasing GPC was associated with increased PCSM risk in men with or without ComboGS adjusting for risk group, age, and treatment.
  
  
  RESULTS
  After a median follow-up of 5.36 years (interquartile range, 3.22-7.61 years), 92 (28%) men died, 28 (30%) of PC. Increasing GPC was significantly associated with increased risk of PCSM (adjusted hazard ratio, 1.02; 95% confidence interval, 1.01-1.03; P = .005). Men with GPC ≥ 50% versus < 50% had significantly greater PCSM estimates when ComboGS was present (P < .001) versus absent (P = .55). Of the 127 men with ComboGS and GPC < 50%, 83% were treated with RT alone and 2 PC deaths were observed; neither in men with GS 7 and favorable intermediate-risk PC.
  
  
  CONCLUSIONS
  Men treated with RT for ComboGS, GPC < 50%, GS 7, and favorable intermediate-risk PC have a very low risk of early PCSM. The RTOG 0815 trial will establish whether ADT is necessary to optimize curability in these men.
authors.affiliation: Harvard Radiation Oncology Program, Boston, MA. Electronic address: mcheney@lroc.harvard.edu.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Cheney
authors.affiliation: Department of Statistics, University of Connecticut, Storrs, CT.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Chen
authors.affiliation: Department of Statistics, University of Connecticut, Storrs, CT.
authors.forename: Danjie
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Harvard Radiation Oncology Program, Boston, MA.
authors.forename: John G
authors.initials: JG
authors.lastname: Phillips
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA.
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Loffredo
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA.
authors.forename: Anthony V
authors.initials: AV
authors.lastname: D'Amico
mesh_terms: D000726:Androgen Antagonists / Q000627:therapeutic use*; D001707:Biopsy, Needle / Q000401:mortality*; D002423:Cause of Death; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D011879:Radiotherapy Dosage; D012307:Risk Factors; D015996:Survival Rate; D047368:Tumor Burden
chemical_list: D000726:Androgen Antagonists
keywords: Androgen deprivation therapy; Biopsy; Needle; Prognosis; Prostatic neoplasms; Radiation therapy