title: Long-term results of conformal radiotherapy for prostate cancer: impact of dose escalation on biochemical tumor control and distant metastases-free survival outcomes.
abstract: OBJECTIVE
  To report prostate-specific antigen (PSA) relapse-free survival and distant metastases-free survival (DMFS) outcomes for patients with clinically localized prostate cancer treated with high-dose conformal radiotherapy.
  
  
  METHODS
  Between 1988 and 2004, a total of 2,047 patients with clinically localized prostate cancer were treated with three-dimensional conformal radiotherapy or intensity-modulated radiotherapy. Prescribed dose levels ranged from 66-86.4 Gy. Median follow-up was 6.6 years (range, 3-18 years).
  
  
  RESULTS
  Although no differences were noted among low-risk patients for the various dose groups, significant improvements were observed with higher doses for patients with intermediate- and high-risk features. In patients with intermediate-risk features, multivariate analysis showed that radiation dose was an important predictor for improved PSA relapse-free survival (p < 0.0001) and improved DMFS (p = 0.04). In patients with high-risk features, multivariate analysis showed that the following variables predict for improved PSA relapse-free survival: dose (p < 0.0001); age (p = 0.0005), and neoadjuvant-concurrent androgen deprivation therapy (ADT; p = 0.01). In this risk group, only higher radiation dose was an important predictor for improved DMFS (p = 0.04).
  
  
  CONCLUSIONS
  High radiation dose levels were associated with improved biochemical tumor control and decreased risk of distant metastases. For high-risk patients, despite the delivery of high radiation dose levels, the use of ADT conferred an additional benefit for improved tumor control outcomes. We observed a benefit for ADT in high-risk patients who received higher doses.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. zelefskm@mskcc.org
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.forename: Zvi
authors.initials: Z
authors.lastname: Fuks
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Margie
authors.initials: M
authors.lastname: Hunt
authors.forename: Oren
authors.initials: O
authors.lastname: Cahlon
authors.forename: Jessica
authors.initials: J
authors.lastname: Park
authors.forename: Alison
authors.initials: A
authors.lastname: Shippy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control*; D009518:New York / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000628:therapy*; D011878:Radiotherapy / Q000706:statistics & numerical data*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016896:Treatment Outcome