Intensity-modulated radiotherapy for the treatment of pelvic lymph nodes in prostate cancer.

Evaluation of: Wang-Chesebro A, Xia P, Coleman J, Akazawa C, Roach M 3rd: Intensity-modulated radiotherapy improves lymph node coverage and dose to critical structures compared with 3D conformal radiation therapy in clinically localized prostate cancer. Int. J. Radiat. Oncol. Biol. Phys. 66, 654-662 (2006). A large randomized Phase III trial (RTOG 94-13) demonstrated improved progression-free survival for the irradiation of the pelvic lymphatics compared with treatment of the prostate only in patients with a high risk of lymph node involvement. Recent studies have indicated that the conventional target volume might miss substantial parts of the lymphatic drainage of the prostate. This retrospective planning study compared conventional, 3D-conformal and intensity-modulated radiotherapy (IMRT) for the treatment of pelvic lymph nodes. Field-shaping based on bony landmarks was shown to result in inadequate target coverage compared with 3D-conformal and IMRT planning. Regarding sparing of rectum, bladder, small bowl and penile bulb, the IMRT plans were highly superior. In summary, IMRT may result in increased rates of regional control with simultaneously decreased rates of toxicity. Integration of functional imaging into treatment planning and image guidance during treatment is expected to further improve the therapeutic ratio.