THE ROLE OF RADIOTHERAPY IN THE MANAGEMENT OF LOCALLY ADVANCED PROSTATE-CANCER

Objective. The article explores the contemporary use of radiation therapy in the management of locally advanced prostate cancer. Methods. The three main radiotherapeutic strategies that have been utilized in current clinical trials to optimize radiotherapy in the management of locally advanced prostate cancers are reviewed. These are to (1) increase the relative integral dose; (2) decrease the volume of tumor present; (3) optimize the biology. Results. Results from the brachytherapy literature demonstrate that high doses may sterilize tumors more effectively. This concept has been taken into trials using conformal external beam radiation therapy. The Phase III trials conducted through the RTOG and in Canada are reviewed. These trials have demonstrated disease-free survival advantages of cytoreduction over conventional therapy alone. Neutron radiation therapy has also been evaluated in multicenter randomized studies, and the results there have demonstrated a superiority for neutron therapy over conventional photon therapy alone. Conclusions. Although conventional photon radiation therapy may not be optimal in bulky prostate cancer, new techniques of optimizing radiation therapy by reducing the volume of tumor present or using techniques that give a biologically optimized dose or a physically increased dose may be of advantage in the future.