The current standard for treating patients with esophageal cancer is 3D radiation, but newer technologies such as intensity-modulated radiation therapy (IMRT) and proton therapy have shown the ability to reduce toxicity by limiting radiation to the surrounding tissue.
http://www.cancernetwork.com/videos-gastrointestinal-cancers/imrt-vs-proton-therapy-esophageal-cancer
IMRT vs Proton Therapy in Esophageal Cancer