title: Intensity modulated radiotherapy of upper abdominal malignancies: dosimetric comparison with 3D conformal radiotherapy and acute toxicity.
abstract: BACKGROUND
  The goal of this study was to assess a possible dosimetric advantage of intensity modulated radiotherapy (IMRT) of upper abdominal malignancies compared to three-dimensional conformal radiotherapy (3DCRT), and to assess the impact of IMRT on acute toxicity.
  
  
  METHODS
  Thirty-one unselected consecutive patients with upper abdominal malignancies were treated with definitive (n =16) or postoperative (n =15) IMRT. Twenty-one patients (67.7%) received concomitant chemotherapy. 3DCRT plans were generated for comparison, and analysis of variance (ANOVA) for repeated measurements was used to test for significant difference of dosimetric parameters. Acute toxicity was assessed weekly using the Common Terminology Criteria for Adverse Events (CTCAE) grading scale.
  
  
  RESULTS
  IMRT plans showed a small but statistically significant improvement of the conformity index compared to 3DCRT plans (difference (95% confidence interval), -0.06 (-0.109 to-0.005); p = 0.03). The homogeneity index was not significantly improved (p = 0.10). A significantly reduced high dose volume on cost of a significantly increased low dose volume was observed for the kidneys. The acute toxicity appeared to be less than commonly reported for corresponding patients treated with 3DCRT. No patient developed grade 3 or 4 non-hematological acute toxicity, and the most common grade 2 toxicity was vomiting (9.7%).
  
  
  CONCLUSIONS
  IMRT offers the potential of a clinically relevant dosimetric advantage compared to 3DCRT in terms of a reduced acute toxicity. Further optimization of the radiotherapy technique and more clinical trials are required before IMRT is routinely used for upper abdominal malignancies.
authors.affiliation: Department of Radiation Oncology, Saad Specialist Hospital, P,O, Box 30353, Al Khobar 31952, Saudi Arabia. volker.rudat@gmail.com.
authors.forename: Alaa Ahmad
authors.initials: AA
authors.lastname: Nour
authors.forename: Aziz
authors.initials: A
authors.lastname: Alaradi
authors.forename: Adel
authors.initials: A
authors.lastname: Mohamed
authors.forename: Saleh
authors.initials: S
authors.lastname: Altuwaijri
authors.forename: Volker
authors.initials: V
authors.lastname: Rudat
mesh_terms: D000008:Abdominal Neoplasms / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*