Dosimetric comparison of 3DCRT and IMRT in radical chemoradiotherapy of squamous cell carcinoma esophagus.

Background: Radical chemoradiation is the standard of treatment for locally advanced squamous cell carcinoma of esophagus and for patients with operable disease, but who are medically unfit or unwilling for surgery. As the esophagus is a central organ, the planning target volume (PTV) is central, lies close to the spinal cord and heart, and is surrounded by the lung, which is a radiosensitive organ. Irradiation of these critical structures is reduced by the use of three-dimensional conformal radiation therapy (3DCRT).