Tongue-out versus tongue-in position during Intensity-Modulated Radiotherapy for base of tongue cancer: Clinical implications for minimizing post-Radiotherapy Swallowing Dysfunction

Abstract

Background

The purpose of this study was to assess whether different tongue positions change the radiation doses to swallowing organs at risks: the pharyngeal constrictor, oral cavity, and larynx during intensity-modulated radiotherapy (IMRT) for base of tongue (BOT) cancer.

Methods

IMRT plans with Tongue-out (IMRT-TO) and tongue-in position (IMRT-TI) was compared in 3 cases.

Results

Distance from BOT to pharyngeal constrictor was increased to 1.8 ± 0.8 cm with IMRT-TO from 0.9 ± 0.6 cm with IMRT-TI (P < .01). Compared to IMRT-TI, IMRT-TO significantly decreased the radiation dose to the anterior oral cavity, oral tongue, superior pharyngeal constrictor, middle pharyngeal constrictor, and supraglottic larynx (all P ≤ .04). IMRT-TO also had a smaller volume irradiated than IMRT-TI to the anterior oral cavity and the oral tongue receiving ≥30 Gy (V30) and V35, and superior pharyngeal constrictor and middle pharyngeal constrictor for V55 and V65 (all P ≤ .04).

Conclusion

Dosimetric advantage with IMRT-TO over IMRT-TI may potentially reduce post-IMRT swallowing dysfunction in selected patients with BOT cancer.

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