Room: Exhibit Hall
Purpose: Radiation dose to vertebral bone (VB) marrow could lead to a decreased blood count, which precludes patients from receiving chemotherapy. Traditionally, dose constraint to VB is not established during treatment planning for esophageal cancer. The purpose of this study is to compare dosimetric differences to organ-at-risk (OARs) using proton therapy, volumetric modulated arc therapy (VMAT) and static intensity modulated radiation therapy (IMRT) for esophageal cancer.
Methods: 18 patients with esophageal cancer were included in this study. Three treatment plans were generated for each patient using passive-scattering proton beams, VMAT and static-IMRT. All plans were prescribed to 50.4 Gy in 28 fractions and generated in Eclipse treatment planning system. In addition to dose constraints to typical OARs, dose constraints to VB were set to Vâ‚?â‚€ < 260 cc and Vâ‚‚â‚€ < 225 cc based on a previous study carried out in our institute. DVH data for VB, lung, heart and liver were evaluated in proton therapy, VMAT and static-IMRT plans.
Results: Majority dosimetric parameters of OARs from proton plans were generally lower than that from VMAT and static-IMRT plans. The average Vâ‚?â‚€, Vâ‚‚â‚€ and mean dose of VB from proton were 141.6cc, 107.2cc and 11.21Gy respectively, and those from VMAT were 207.73cc, 133.98cc and 13.66Gy respectively, and 217.97cc, 157.99cc and 15.78Gy from static-IMRT. The average mean dose of heart, lung and liver from proton were 14.6 Gy, 9.6 Gy and 5.5 Gy, and those from VMAT were 17.1 Gy, 12.9 Gy and 14.7 Gy respectively, and 18.5 Gy, 12.3 Gy and 11.8 Gy from static-IMRT.
Conclusion: The passive-scattering proton beam therapy has lower mean dose to OARs compared to VMAT and static IMRT for esophageal cancer in our study. The reduced VB dose from proton therapy could be beneficial for esophageal cancer patients undergoing chemoradiation therapy.