Prostate cancer is associated with a risk of lymph node involvement, which increases with clinical stage, Gleason score, and PSA level at diagnosis. When this risk is higher than 15%, it has been suggested to irradiate the pelvis in addition to the prostate despite an increased risk of gastrointestinal toxicities. However, several randomized trials seem to call into question this therapeutic approach. This review presents the potent role of pelvic irradiation in the treatment of locally advanced prostate cancer treated with exclusive radiotherapy.