Men who underwent radiation treatment after a radical prostatectomy followed by prostate cancer recurrence had improved cancer-related survival rates, according to new research published in the June 18 issue if JAMA.
Researcher Bruce J. Trock, Ph.D. (Johns Hopkins University School of Medicine, Baltimore) and colleagues note that, “Nearly 60,000 men (27 percent of newly diagnosed cases) will have undergone radical prostatectomy in 2007. Although surgery provides excellent cancer control, approximately 15 percent to 40 percent of these men will experience cancer recurrence within 5 years, usually manifested only by elevated prostate-specific antigen (PSA) level.” This present study analyzes such men to see if salvage radiotherapy – treatment with radiation provided after cancer recurs – can lead to better survival rates than observation alone.
To investigate the potential link between salvage radiotherapy and prostate cancer-specific survival, the researchers conducted a study that consisted of 635 men who underwent radical prostatectomy from 1982-2004 and experienced biochemical recurrence (as determined by increases in PSA levels) and/or local cancer recurrence. Of the total, 397 men received either no salvage treatment, 160 men received salvage radiotherapy alone, and 78 received salvage radiotherapy combined with hormonal therapy. They were followed up through December 2007.
After a median follow-up time of 6 years after cancer recurrence and 9 years after prostatectomy, 18% (116 of 397 men) died from prostate cancer. Specifically, 22% (89 of 397 men) of those who received no salvage treatment died, 11% (18 of 160 men) of those who received salvage radiotherapy alone died, and 12% (9 of 78 men) of those who received salvage radiotherapy and hormonal therapy together died. A main finding was the statistically significantly decrease in the risk of death of about 60% for those who received salvage radiotherapy – whether alone or with hormonal therapy. In addition, the researchers report a 3-times increase in prostate cancer-specific survival rates for those who received salvage treatment compared to those who did not. Patients who received salvage radiotherapy at all had significantly increased survival rates.
Among men with PSA doubling times of less than 6 months, those with salvage radiotherapy had increases in prostate cancer-specific survival rates. Of the total sample, 26% (166 men) has PSA doubling times of less than 6 months. For these men, salvage radiotherapy alone and salvage therapy with hormonal treatment were found to reduce the risk of prostate cancer-specific death by over 75%. Only if salvage radiotherapy was administered two years after cancer recurrence was it associated with an increase in survival.
The researchers reported a significant increase in prostate cancer-specific survival for those men whose PSA could not be detected after salvage radiotherapy.
“This study provides provocative evidence that even men with adverse prognostic features such as rapid PSA doubling time or high Gleason score [a grading system for prostate cancer] may benefit from salvage radiotherapy,” write the authors.
They conclude that, “Our data provide the first evidence (albeit retrospective and hence, provisional) that early salvage radiotherapy is associated with improved prostate cancer-specific survival, and the magnitude of the survival benefit is similar to that observed in adjuvant [supplemental] radiotherapy trials. These data suggest that men for whom salvage radiotherapy is most beneficial are those with a PSA doubling time of less than 6 months, who also undergo treatment within 2 years of an increase in PSA level. If validated in other settings, these results could motivate a clinical trial comparing adjuvant with salvage radiotherapy, with prostate cancer-specific survival and overall survival as the primary end points.”
Prostate Cancer-Specific Survival Following Salvage Radiotherapy vs Observation in Men With Biochemical Recurrence After Radical Prostatectomy
Bruce J. Trock; Misop Han; Stephen J. Freedland; Elizabeth B. Humphreys; Theodore L. DeWeese; Alan W. Partin; Patrick C. Walsh
JAMA (2008). 299[23]: pp. 2760 – 2769.
Written by: Peter M Crosta