Does Treatment Duration Affect Outcome After Radiotherapy for Prostate Cancer?

David J. D'Ambrosio, Tianyu Li, Eric M. Horwitz, David Y.T. Chen, Alan Pollack, Mark K. Buyyounouski

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Purpose: The protraction of external beam radiotherapy (RT) time is detrimental in several disease sites. In prostate cancer, the overall treatment time can be considerable, as can the potential for treatment breaks. We evaluated the effect of elapsed treatment time on outcome after RT for prostate cancer. Methods and Materials: Between April 1989 and November 2004, 1,796 men with prostate cancer were treated with RT alone. The nontreatment day ratio (NTDR) was defined as the number of nontreatment days divided by the total elapsed days of RT. This ratio was used to account for the relationship between treatment duration and total RT dose. Men were stratified into low risk (n = 789), intermediate risk (n = 798), and high risk (n = 209) using a single-factor model. Results: The 10-year freedom from biochemical failure (FFBF) rate was 68% for a NTDR <33% vs. 58% for NTDR ≥33% (p = 0.02; BF was defined as a prostate-specific antigen nadir + 2 ng/mL). In the low-risk group, the 10-year FFBF rate was 82% for NTDR <33% vs. 57% for NTDR ≥33% (p = 0.0019). The NTDR was independently predictive for FFBF (p = 0.03), in addition to T stage (p = 0.005) and initial prostate-specific antigen level (p < 0.0001) on multivariate analysis, including Gleason score and radiation dose. The NTDR was not a significant predictor of FFBF when examined in the intermediate-risk group, high-risk group, or all risk groups combined. Conclusions: A proportionally longer treatment duration was identified as an adverse factor in low-risk patients. Treatment breaks resulting in a NTDR of ≥33% (e.g., four or more breaks during a 40-fraction treatment, 5 d/wk) should be avoided.

Original languageEnglish (US)
Pages (from-to)1402-1407
Number of pages6
JournalInternational Journal of Radiation Oncology Biology Physics
Volume72
Issue number5
DOIs
StatePublished - Dec 1 2008
Externally publishedYes

Keywords

  • Biochemical failure
  • Prostate
  • Prostate-specific antigen
  • Radiotherapy
  • Treatment break

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation
  • Cancer Research

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