Optimizing laryngeal sparing with intensity modulated radiotherapy or volumetric modulated arc therapy for unilateral tonsil cancer

Amy C. Moreno, Christopher Wilke, He Wang, Shi Ming Samuel Tung, Courtney Pollard, Adam S. Garden, William H. Morrison, David I. Rosenthal, Clifton D. Fuller, Gary B. Gunn, Jay P. Reddy, Shalin J. Shah, Steven J. Frank, Vinita Takiar, Jack Phan

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background and purpose: Minimizing radiation dose exposure to nearby organs is key to limiting clinical toxicities associated with radiotherapy. Several treatment modalities such as split- or whole-field intensity-modulated radiotherapy (SF-IMRT, WF-IMRT)and volumetric modulated arc therapy (VMAT)are being used to treat tonsillar cancer patients with unilateral neck radiotherapy. Herein, we provide a modern dosimetric comparison of all three techniques. Materials and methods: Forty patients with tonsillar cancer treated with definitive, ipsilateral neck SF-IMRT were evaluated. Each patient was re-planned with WF-IMRT and VMAT techniques, and doses to selected organs-at-risk (OARs)including the larynx, esophagus, and brainstem were compared. Results: No significant differences in target coverage existed between plans; however, the heterogeneity index improved using WF-IMRT and VMAT relative to SF-IMRT. Compared to SF-IMRT, WF-IMRT and VMAT plans had significantly lower mean doses to the supraglottic larynx (31 Gy, 18.5 Gy, 17 Gy; p < 0.01), the MDACC-defined larynx (13.4 Gy, 10.5 Gy, 9.8 Gy; p < 0.01), and RTOG-defined larynx (15.8 Gy, 12.1 Gy, 11.1 Gy; p < 0.01), respectively. Mean esophageal dose was lowest with SF-IMRT over WF-IMRT and VMAT (5.9 Gy, 12.2 Gy, 11.1 Gy; p < 0.01)but only in the absence of lower neck disease. On average, VMAT plans had shorter treatment times and required less monitor units than both SF-IMRT and WF-IMRT. Conclusion: In the setting of unilateral neck radiotherapy, WF-IMRT and VMAT plans can be optimized to significantly improve dose sparing of critical structures compared to SF-IMRT. VMAT offers additional advantages of shorter treatment times and fewer required monitor units.

Original languageEnglish (US)
Pages (from-to)29-34
Number of pages6
JournalPhysics and Imaging in Radiation Oncology
StatePublished - Apr 2019

Bibliographical note

Publisher Copyright:
© 2019


  • Dosimetry
  • IMRT
  • Oropharynx
  • Split-field
  • Tonsillar cancer
  • Unilateral neck radiotherapy
  • VMAT


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