(HealthDay News) — Observation should be the standard approach after a prostatectomy for men with localized prostate cancer, with radiotherapy (RT) saved for if and when the cancer comes back, according to two studies presented at the European Society of Medical Oncology Congress 2019, held from Sept. 27 to Oct. 1 in Barcelona, Spain.
Chris Parker, M.D., from the Institute of Cancer Research/Royal Marsden NHS Foundation Trust in Sutton, United Kingdom, and colleagues used data from 1,396 participants in the RADICALS-RT trial to compare the efficacy and safety of adjuvant RT (aRT) versus an observation policy with salvage RT (sRT) for prostate-specific antigen failure for men with postoperative prostate-specific antigen ≤0.2 ng/mL and at least one risk factor (pT3/4, Gleason 7 to 10, positive margins, or preoperative PSA ≥10 ng/mL). The researchers found that based on 169 events at a median follow-up of 5 years, progression-free survival was similar between the two groups (hazard ratio, 1.10; 95 percent confidence interval, 0.81 to 1.49; P = 0.56).
Claire L. Vale, Ph.D., from University College London, and colleagues prospectively planned a series of meta-analyses of three randomized trials (RADICALS, GETUG-AFU 17, and RAVES) that compared aRT with sRT after radical prostatectomy for men with localized prostate cancer. Based on 245 events, the researchers observed no evidence that event-free survival is improved with aRT compared with sRT (hazard ratio, 1.09; 95 percent confidence interval, 0.86 to 1.39; P = 0.47). At five years, this finding translates to a potential absolute difference of 1 percent in favor of sRT.
“The results suggest that radiotherapy is equally effective whether it is given to all men shortly after surgery or given later to those men with recurrent disease,” Parker said in a statement. “There is a strong case now that observation should be the standard approach after surgery and radiotherapy should only be used if the cancer comes back.”
Several authors from both studies disclosed financial ties to the pharmaceutical industry.