Early Radiation Boosts Prostate Cancer Survival
Published February 15, 2013 / By Charles Bankhead / MedPage Today
Immediate radiation therapy after radical prostatectomy led to a 50% increase in long-term biochemical progression-free survival (bNED) for patients with locally advanced prostate cancer, according to a study reported here.
After a median follow-up of almost 10 years, patients who received immediate adjuvant radiotherapy had a bNED rate of 61% compared with 40% for patients randomized to a "wait-and-see" strategy that depended on a return of detectable PSA levels, Thomas Wiegel, MD, said at the Genitourinary Cancers Symposium.
Patients with positive surgical margins benefited the most from immediate radiotherapy, reflected in a bNED rate of 55% versus 27% for patients randomized to the wait-and-see (salvage) approach.
Overall survival and distant metastasis-free survival did not differ between groups, primarily because of low rates of qualifying events in both groups, said Wiegel, of the University of Ulm in Germany.
"The greatest impact was observed in patients who had positive surgical margins and those with pT3a/b disease," said Wiegel. "Adjuvant radiation therapy had no influence on overall survival, but the trial was not statistically powered for a survival analysis.
"There was a low rate of late side effects, and a low rate of overtreatment of patients with locally advanced disease and positive surgical margins."
The findings corroborated but also clarified the benefits of adjuvant radiation therapy for locally advanced prostate cancer (pT3 R1/0).
A European cooperative-group trial showed a 20% improvement in bNED 10 years after diagnosis, but no effect on overall or metastasis-free survival (Lancet 2012; 380: 2018-2027). In contrast, investigators in the U.S. found that immediate radiation therapy improved all three outcomes after 12 years of follow-up (J Urol 2009; 181: 956-962).
Wiegel and colleagues previously reported improved 5-year bNED with immediate radiation therapy but no difference in overall or metastasis-free survival (J Clin Oncol 2009; 27: 2924-2930). The results remained unchanged after another 5 years of follow-up.