Adjuvant external radiation therapy following radical prostatectomy for node-negative prostate cancer

The use of adjuvant radiation therapy following prostatectomy is commonplace. The purpose of this review is to summarize completed and ongoing clinical trials and to review recent relevant studies and debates related to this subject.

The routine use of adjuvant radiation therapy remains a controversial topic. Recent retrospective matched-pair analyses support its use in appropriately selected patients with positive margins, extraprostatic extension or seminal vesicle invasion, but interpretation of these and other data vary. Although the 5-year biochemical recurrence rate using adjuvant radiotherapy may be decreased from approximately 40 to 10% in patients with either positive margins or extraprostatic extension, its effect on cause-specific mortality is unclear. Two prospective randomized trials with cumulative enrollment of over 1400 patients have examined the role of adjuvant radiation therapy compared with observation following prostatectomy: one trial was a National Cancer Institute-sponsored Intergroup study coordinated by the Southwest Oncology Group, and the other was from the European Organization for Research and Treatment of Cancer. Currently, the Radiation Therapy Oncology Group is conducting a three-arm trial, with broadened stratification criteria as compared with previous trials. This ongoing trial examines the use of adjuvant radiotherapy with or without adjuvant androgen deprivation following prostatectomy and also androgen deprivation alone in patients at high risk for disease relapse.

In lieu of data from completed randomized trials, indications for immediate adjuvant radiation therapy following prostatectomy exist and are supported by retrospective data with respect to reducing local and biochemical recurrence rates. However, data demonstrating an overall or cause-specific survival advantage for adjuvant radiotherapy as compared with delayed salvage therapy do not exist.