Department of Radiation OncologyMayo Clinic, Jacksonville, FL.

To investigate the association between external beam radiotherapy (EBRT) dose and biochemical failure (BcF) of prostate cancer in patients who received salvage prostate bed EBRT for a rising prostate-specific antigen (PSA) level after radical prostatectomy.

We evaluated patients with a rising PSA level after prostatectomy who received salvage EBRT between July 1987 and October 2007. Patients receiving pre-EBRT androgen suppression were excluded. Cox proportional hazards models were used to investigate the association between EBRT dose and BcF. Dose was considered as a numeric variable and as a categoric variable (low, < 64.8 Gy; moderate, 64.8-66.6 Gy; high, >66.6 Gy).

A total of 364 men met study selection criteria and were followed up for a median of 6.0 years (range, 0.1-19.3 years). Median pre-EBRT PSA level was 0.6 ng/mL. The estimated cumulative rate of BcF at 5 years after EBRT was 50% overall and 57%, 46%, and 39% for the low-, moderate-, and high-dose groups, respectively. In multivariable analysis adjusting for potentially confounding variables, there was evidence of a linear trend between dose and BcF, with risk of BcF decreasing as dose increased (relative risk [RR], 0.77 [5.0-Gy increase]; p = 0.05). Compared with the low-dose group, there was evidence of a decreased risk of BcF for the high-dose group (RR, 0.60; p = 0.04), but no difference for the moderate-dose group (RR, 0.85; p = 0.41).

Our results suggest a dose response for salvage EBRT. Doses higher than 66.6 Gy result in decreased risk of BcF.

Written by:
Bernard JR Jr, Buskirk SJ, Heckman MG, Diehl NN, Ko SJ, Macdonald OK, Schild SE, Pisansky TM. Are you the author?

Reference:
Int J Radiat Oncol Biol Phys. 2009 May 21. Epub ahead of print.
doi:10.1016/j.ijrobp.2009.02.049

PubMed Abstract
PMID:19464818

UroToday.com Prostate Cancer Section

Please log-in or register in order to submit comments.

Powered by AkoComment!