Lawton CA et al. (2007) An update of the phase III trial comparing whole pelvic to prostate only radiotherapy and neoadjuvant to adjuvant total androgen suppression: updated analysis of RTOG 94-13, with emphasis on unexpected hormone/radiation interactions. Int J Radiat Oncol Biol Phys 69: 646–655

Standard treatment of localized intermediate and/or high-risk prostate cancer comprises external-beam radiotherapy and hormonal therapy. This combination improves overall survival, but there is still some controversy surrounding the value of pelvic lymph node irradiation, as well as the timing of androgen suppression. The Radiation Therapy Oncology Group (RTOG) study 94-13 was designed to investigate whether whole pelvic radiotherapy (WPRT) is better than prostate-only radiotherapy (PORT) for high-risk disease and how neoadjuvant hormone therapy (NHT) compared with adjuvant hormone therapy (AHT).

The study comprised 1,292 patients with locally advanced adenocarcinoma of the prostate and a minimum of 15% lymph node involvement. There were four treatment arms: WPRT + NHT, WPRT + AHT, PORT + NHT, and PORT + AHT. This study revealed no statistically significant differences in overall survival; the only trend towards an improvement in progression-free survival was observed in the WPRT + NHT arm compared with the PORT + NHT and WPRT + AHT arms. There seems to have been an unexpected interaction between the timing of the hormone therapy and the scope of the radiation therapy.

Lawton et al. recommended further studies to find out whether this failure to demonstrate a significant advantage for WPRT + NHT compared with PORT + AHT is down to chance, or whether there is a biological explanation.