Delivering radiation therapy immediately after radical prostatectomy resulted in fewer cases of biochemical progression of prostate cancer, compared with a "wait-and-see" approach, according to long-term data from a randomized phase III trial.
However, no such effect on overall survival was seen, with a possible detrimental effect in patients older than 70 years, investigators reported online Oct. 19 in the Lancet (doi: 10.1016/S0140-6736(12)61253-7).
Dr. Michel Bolla, of the Centre Hospitalier Universitaire A Michallon in Grenoble, France, and his colleagues looked at 1,005 men enrolled in the European Organisation for Research and Treatment of Cancer (EORTC) 22911 trial, who were followed for a median of 10.6 years.
The cohort (median age 65 years) included patients with untreated adenocarcinoma of the prostate and at least one of the following: capsular perforation, positive surgical margins, or seminal vesicle invasion.
All patients underwent radical prostatectomy, and were then randomly assigned either to receive immediate postoperative external irradiation (within 16 weeks of surgery) or to a "wait-and-see" policy, whereby subsequent treatment was delayed until biochemical or clinical relapse.
Overall, Dr. Bolla and his coauthors found that 198 patients (39.4%) in the postoperative radiation group had biochemical progression (defined as an increase in prostate-specific antigen concentration to more than 0.2 mcg/L measured on two occasions at least 2 weeks apart), clinical progression, or died.
In contrast, the "wait-and-see" group recorded 311 patients (61.8%) who either progressed or died, for a hazard ratio of 0.49 for the radiation approach (P less than .0001).
Stratifying the results by age showed that patients under 70 years old had improved biochemical progression-free survival (hazard ratio, 0.44; P less than .0001) and clinical progression-free survival (HR, 0.67; P = .0013) in the radiation cohort compared with wait-and-see patients.
However, "excess mortality was seen in patients aged 70 years or older who had received immediate radiation compared with those aged 70 years or older who were on the wait-and-see policy," they wrote, with 40 deaths out of 94 older patients in the radiation group versus 20 deaths out of 102 patients in the wait-and-see group (HR, 2.94; P less than .0001).
Finally, looking at the entire cohort, the authors found that overall all-cause 10-year survival did not differ substantially, at 76.9% for the postoperative radiation patients and 80.7% for the wait-and-see group.
"Prostate cancer mortality did not differ significantly between groups either," added the authors.
Dr. Bolla and his colleagues said they had no conflicts of interest related to this study, which was funded by the Ligue Nationale contre le Cancer and the EORTC Charitable Trust.