Radiotherapy Doses of 80 Gy and Higher Are Associated With Lower Mortality in Men With Gleason Score 8 to 10 Prostate Cancer

Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1949-56. doi: 10.1016/j.ijrobp.2011.04.005. Epub 2011 Jul 15.

Abstract

Purpose: Men with Gleason score (GS) 8-10 prostate cancer (PCa) are assumed to have a high risk of micrometastatic disease at presentation. However, local failure is also a major problem. We sought to establish the importance of more aggressive local radiotherapy (RT) to ≥80 Gy.

Methods and materials: There were 226 men treated consecutively with RT ± ADT from 1988 to 2002 for GS 8-10 PCa. Conventional, three-dimensional conformal or intensity-modulated (IM) RT was used. Radiation dose was divided into three groups: (1) <75 Gy (n = 50); (2) 75-79.9 Gy (n = 60); or (3) ≥80 Gy (n = 116). The endpoints examined included biochemical failure (BF; nadir + 2 definition), distant metastasis (DM), cause-specific mortality, and overall mortality (OM).

Results: Median follow-up was 66, 71, and 58 months for Groups 1, 2, and 3. On Fine and Gray's competing risk regression analysis, significant predictors of reduced BF were RT dose ≥80 Gy (p = 0.011) and androgen deprivation therapy duration ≥24 months (p = 0.033). In a similar model of DM, only RT dose ≥80 Gy was significant (p = 0.007). On Cox regression analysis, significant predictors of reduced OM were RT dose ≥80 Gy (p = 0.035) and T category (T3/4 vs. T1, p = 0.041). Dose was not a significant determinant of cause-specific mortality. Results for RT dose were similar in a model with RT dose and ADT duration as continuous variables.

Conclusion: The results indicate that RT dose escalation to ≥80 Gy is associated with lower risks of BF, DM, and OM in men with GS 8-10 PCa, independently of androgen deprivation therapy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Androgen Antagonists / therapeutic use
  • Endpoint Determination
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Grading
  • Prostate / radiation effects
  • Prostatic Neoplasms / mortality*
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy*
  • Radiotherapy Dosage
  • Radiotherapy, Conformal / methods
  • Radiotherapy, Intensity-Modulated / methods
  • Regression Analysis
  • Seminal Vesicles / radiation effects
  • Survival Analysis

Substances

  • Androgen Antagonists