Preliminary findings indicate that for men who underwent radical prostatectomy, radiation treatment after prostate cancer recurrence was associated with an increase in prostate cancer-related survival, according to a study in the June 18 issue of JAMA.
“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,” the authors write. For such men it is unknown whether salvage radiotherapy (radiation treatment given after recurrence of cancer) offers a survival benefit compared with observation alone.
Bruce J. Trock, Ph.D., of the Johns Hopkins University School of Medicine, Baltimore, and colleagues conducted a study to determine the association between salvage radiotherapy and prostate cancer–specific survival. The study included 635 men who underwent radical prostatectomy from 1982-2004, were followed up through December 2007, and who experienced biochemical recurrence (increased PSA levels) and/or local cancer recurrence and received either no salvage treatment (n = 397), salvage radiotherapy alone (n = 160), or salvage radiotherapy combined with hormonal therapy (n = 78).
With a median (midpoint) follow-up of 6 years after recurrence and 9 years after prostatectomy, 116 men (18 percent) died from prostate cancer, including 89 (22 percent) who received no salvage treatment, 18 (11 percent) who received salvage radiotherapy alone, and 9 (12 percent) who received salvage radiotherapy and hormonal therapy. The researchers found that salvage radiotherapy, regardless of whether given alone or with hormonal therapy, was associated with a statistically significant decrease in the risk of death of nearly 60 percent and a 3-fold increase in prostate cancer–specific survival relative to those who received no salvage treatment. Salvage radiotherapy was also associated with a significant increase in overall survival.
The increase in prostate cancer–specific survival associated with salvage radiotherapy was limited to men with PSA doubling time (a measurement of how aggressive the disease is) of less than 6 months. Among 166 men (26 percent) with PSA doubling time of less than 6 months, salvage radiotherapy alone and salvage therapy with hormonal treatment were associated with a reduction in risk of prostate cancer–specific death by more than 75 percent. Salvage radiotherapy was associated with an increase in survival only if given sooner than 2 years after recurrence.
Men whose PSA level never became undetectable after salvage radiotherapy did not experience a significant increase in prostate cancer–specific survival.
“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,” the authors write.
“… 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.”
JAMA. 2008; 299:2760-2769