Background: Esophageal cancer was previously treated with 3-dimensional conformal radiation therapy (3D-CRT). In order to benefit from the clinical potential of preserving the lung and spinal cord, radiation therapy for esophageal cancer has switched from 3D-CRT to intensity-modulated-radiation-therapy (IMRT).

Aim: It is important to investigate whether esophageal cancer radiotherapy employing flattening filter-free compared to flattened beams has any advantages. The goal of this study is to extensively compare the dosimetric features, delivery effectiveness (response), and toxicity of a treatment regimen for esophageal cancer of Flattening Filter (FF) and Flattening Filter Free (FFF) photon beams using Intensity Modulated Radiation Therapy (IMRT) technology.

Material and Methods: The present study was conducted as a prospective observational study on 60 patients with esophageal cancer undergoing radiation in Department of Radiation oncology, Govt. Medical College of Central India and associated Hospital. All 60 participants were randomly assigned into either of the two treatment group (IMRT-FF and IMRT-FFF) and were compared for dose volume histogram, toxicities and response.

Results: Two groups were comparable with respect to baseline variables and tumor characteristics (p>0.05). Mean and maximum heart dose; minimum, maximum as well as mean dose of left lung; minimum and maximum dose of right lung and minimum and mean dose in spinal cord in IMRT-FF group were significantly higher in IMRT-FF group as compared to IMRT-FFF group (p<0.05). The response was significantly better in FFF group (p<0.05). We found no significant difference in toxicities to organ at risk between two treatment arm (p>0.05).

Conclusion: IMRT FF and IMRT FFF are standard photon beam used for management of patients with esophageal cancers. FFF photon beam in comparison to FF photon beam provides better OAR sparing by less scattered dose, improves quality of life and runs treatment process smoothly. The most beneficial character of FFF beam plan is clinically desirable and physically acceptable treatment plan at lower dose for target coverage and reduction of peripheral dose around target without compromising quality of beam.