Role of intensity-modulated radiation therapy in gastrointestinal cancer.

Intensity-modulated radiation therapy (IMRT) represents a powerful advance in the planning and delivery of radiation therapy owing to its ability to deliver highly conformal treatment doses while sparing normal tissues. Dosimetric studies have shown the feasibility and theoretical benefit of treating with IMRT over 3D-conformal radiation therapy in gastrointestinal malignancies. Early clinical experience with IMRT in the treatment of gastric, pancreatic, rectal and anal cancers corroborates the dosimetric analyses, with some series reporting lower normal tissue toxicities. This article reviews the radiobiological, physical, technical and clinical aspects of IMRT for gastric, pancreatic, rectal and anal cancer, and summarizes the dosimetric and outcome studies to date.