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Scientific article
English

Unilateral radiotherapy for tonsil cancer: potential dose distribution optimization with a simple two-field intensity-modulated radiation therapy beam arrangement

Published inRadiotherapy and oncology, vol. 94, no. 3, p. 334-338
Publication date2010
Abstract

BACKGROUND AND PURPOSE: To evaluate the feasibility and dosimetric optimization potential of a unilateral two-field intensity-modulated radiotherapy (IMRT) technique in the curative treatment of lateralized tonsil cancer. MATERIALS AND METHODS: Six patients with lateralized tonsillar carcinoma were treated unilaterally with a two-field IMRT technique (oblique-anterior and oblique-posterior fields, with or without collimator and couch rotation). Alternative IMRT plans using seven non-opposed coplanar fields were compared with the two-field plans for each patient. RESULTS: Planning target volume (PTV) coverage was excellent with the two-field technique, using a relatively low number of monitor units (MU) (median, 441; range, 309-550). Dose constraints were respected for all organs at risk (OAR). Mean doses to contralateral parotid and submandibular glands were 3.9 and 17.7 Gy, respectively. Seven-field IMRT provided similar PTV coverage, with statistically significant better dose homogeneity and conformality. However, the mean delivered dose to the contralateral parotid (3.9 vs. 9.0 Gy, p=0.001) as well as the mean number of MU (437 vs. 814, p=0.002) and consequently machine time were lower with two-field IMRT. CONCLUSIONS: Unilateral two-field IMRT is a simple and feasible technique providing excellent tumor coverage and optimal OAR sparing while reducing the number of MU and treatment time.

Keywords
  • Aged
  • Carcinoma, Squamous Cell/pathology/*radiotherapy
  • Female
  • Humans
  • Male
  • Middle Aged
  • Radiotherapy Dosage
  • *Radiotherapy, Intensity-Modulated
  • Tonsillar Neoplasms/pathology/*radiotherapy
Citation (ISO format)
ZILLI, Thomas et al. Unilateral radiotherapy for tonsil cancer: potential dose distribution optimization with a simple two-field intensity-modulated radiation therapy beam arrangement. In: Radiotherapy and oncology, 2010, vol. 94, n° 3, p. 334–338. doi: 10.1016/j.radonc.2009.11.009
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ISSN of the journal0167-8140
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