In the June 18, 2008 edition of JAMA, Dr. Bruce Trock and associates reported on prostate cancer (CaP) specific survival following salvage radiotherapy (XRT) vs. observation in men with biochemical recurrence after radical prostatectomy (RP). They found a benefit to salvage XRT.
Between 1982 and 2004, 926 men developed CaP recurrence following RP with staging pelvic lymphadenectomy at Johns Hopkins Hospital. Men were either observed (OB arm), received salvage XRT (sXRT arm) or salvage XRT with androgen deprivation (sXRT+ADT). Patients were followed up through December 2007. A total of 635 men remained for analysis of the effect of salvage XRT on CaP-specific survival. A single PSA measurement of 0.2ng/ml or higher defined biochemical recurrence. A total of 397 men were in the OB arm, 160 in the XRT arm and 78 in the sXRT+ADT arm. Median follow-up from the date of RP was nine years. Median XRT dose was 66.5Gy.
A total of 116 men died from CaP, and 49 died from other causes. The three arms differed for all prognostic factors except positive surgical margin status. Men with no salvage therapy had a much higher prevalence of positive lymph nodes (30 per cent vs. three per cent). Men in the sXRT+ADT arm had significantly shorter time to recurrence, shorter PSA doubling time, and higher PSA level at the time XRT was initiated. Kaplan-Meier curves showed significant differences in CaP-specific survival with five- and ten-year survivals of 0.88 and 0.62 for the OB arm, 0.96 and 0.86 for the XRT arm, and 0.96 and 0.82 for the sXRT+ADT arm, respectively. In multivariable models, after adjusting for the logarithm of PSADT, time from surgery to recurrence, year of surgery, and postoperative Gleason score, salvage XRT was associated with a statistically significant reduction in risk of death of more than 65 per cent. The association between salvage XRT and CaP-specific survival did not differ according to whether salvage ADT was also given. PSADT dichotomized at six months most strongly separated men for whom salvage XRT was and was not associated with an increase in CaP-specific survival. Among 166 men with a PSADT of less than six months, salvage XRT and sXRT+ADT was associated with a reduction in risk of CaP-specific mortality by more than 75 per cent. This was regardless of whether XRT was initiated less than one year or greater than one year after recurrence or when the PSA was less than two ng/ml or more than two ng/ml. This was also regardless of surgical margin status.
Among men whose PSA levels never became undetectable, the association between salvage XRT and CaP-specific survival was not statistically different.
JAMA 2008 Jun 18;299(23):2760-9 Trock BJ, Han M, Freedland SJ, Humphreys EB, DeWeese TL, Partin AW, Walsh PC
Reported by UroToday.com Contributing Editor Christopher P. Evans, MD, FACS
