title: Feasibility of using intensity-modulated radiotherapy to improve lung sparing in treatment planning for distal esophageal cancer.
abstract: OBJECTIVE
  To evaluate the feasibility whether intensity-modulated radiotherapy (IMRT) can be used to reduce doses to normal lung than three-dimensional conformal radiotherapy (3 DCRT) in treating distal esophageal malignancies.
  
  
  METHODS
  Ten patient cases with cancer of the distal esophagus were selected for a retrospective treatment-planning study. IMRT plans using four, seven, and nine beams (4B, 7B, and 9B) were developed for each patient and compared with the 3 DCRT plan used clinically. IMRT and 3 DCRT plans were evaluated with respect to PTV coverage and dose-volumes to irradiated normal structures, with statistical comparison made between the two types of plans using the Wilcoxon matched-pair signed-rank test.
  
  
  RESULTS
  IMRT plans (4B, 7B, 9B) reduced total lung volume treated above 10 Gy (V(10)), 20 Gy (V(20)), mean lung dose (MLD), biological effective volume (V(eff)), and lung integral dose (P<0.05). The median absolute improvement with IMRT over 3DCRT was approximately 10% for V(10), 5% for V(20), and 2.5 Gy for MLD. IMRT improved the PTV heterogeneity (P<0.05), yet conformity was better with 7B-9B IMRT plans. No clinically meaningful differences were observed with respect to the irradiated volumes of spinal cord, heart, liver, or total body integral doses.
  
  
  CONCLUSIONS
  Dose-volume of exposed normal lung can be reduced with IMRT, though clinical investigations are warranted to assess IMRT treatment outcome of esophagus cancers.
authors.affiliation: Department of Radiation Oncology, University of Texas, M.D. Anderson Cancer Center, Houston, USA.
authors.forename: Anurag
authors.initials: A
authors.lastname: Chandra
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Guerrero
authors.forename: H Helen
authors.initials: HH
authors.lastname: Liu
authors.forename: Susan L
authors.initials: SL
authors.lastname: Tucker
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liao
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Wang
authors.forename: Hasan
authors.initials: H
authors.lastname: Murshed
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bonnen
authors.forename: Amit K
authors.initials: AK
authors.lastname: Garg
authors.forename: Craig W
authors.initials: CW
authors.lastname: Stevens
authors.forename: Joe Y
authors.initials: JY
authors.lastname: Chang
authors.forename: Melinda D
authors.initials: MD
authors.lastname: Jeter
authors.forename: Radhe
authors.initials: R
authors.lastname: Mohan
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
mesh_terms: D004307:Dose-Response Relationship, Radiation; D004938:Esophageal Neoplasms / Q000532:radiotherapy*; D006801:Humans; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D016896:Treatment Outcome