A Dosimetric Comparison of Oral Cavity Sparing in the Unilateral Treatment of Early Stage Tonsil Cancer: IMRT, IMPT, and Tongue-Deviating Oral Stents

Abstract

Introduction Tongue-deviating oral stents (TDOS) are commonly used during unilateral neck radiation therapy to reduce unnecessary dose to nontarget oral structures. Their benefit in the setting of highly conformal treatment techniques, however, is not defined. The goal of this study was to investigate the potential benefit of TDOS use on dosimetric parameters in unilateral intensity modulated radiation therapy (IMRT) and intensity modulated proton therapy (IMPT). Methods A total of 16 patients with T1-2 tonsil cancer treated at a single institution were selected, of which 8 were simulated/treated with a TDOS and 8 without a TDOS. All received definitive unilateral IMRT to a dose of 66 Gy in 30 fx. IMPT plans were generated for each patient for study purposes and optimized according to standard institutional practice. Results For IMRT plans, the presence of a TDOS (vs without) was associated with a significantly lower oral mucosa mean dose (31.4 vs 35.3 Gy; P = .020) and V30 (42.7% vs 57.1%; P = .025). For IMPT plans, the presence of TDOS (vs without) was not associated with any improvement in oral mucosa mean dose (18.3 vs 19.9 Gy; P = .274) or V30 (25.0% vs 26.2%; P = .655). IMPT plans without TDOS compared with IMRT plans with TDOS demonstrated reduced oral mucosa mean dose ( P < .001) and V30 ( P < .001). Conclusion The use of a TDOS for the unilateral treatment of well-lateralized tonsil cancers was associated with oral mucosa sparing for IMRT, but not for IMPT. Moreover, mucosa sparing was improved for IMPT plans without a TDOS compared to IMRT plans with a TDOS.

Toxicity with proton therapy for oral and/or oropharyngeal cancers: A scoping review

“…The total number of patients observed in the included studies varied from 5 31 to 532, 21 with a median age range of 53.3 34 to 66 36 years. Majority of the patients [18][19][20][21][22][23][24][25][26][31][32][33][34][35] were male, which was expected given the increased prevalence of oral and/or oropharyngeal cancer in men. Prescribed doses ranged from 28.6 to 76 GyE for oral and/or oropharyngeal cancer.…”

“…All included studies were of oral and/or oropharyngeal cancer patients. The studies included were based in different countries, including the United States, [18][19][20][21][22][23][24][25][26][27][28][29][30] Switzerland, 31 Japan, 32,33 and Germany. 26,34 All included studies [18][19][20][22][23][24][25][26]31,32,34,35 except five 21,30,33 were prospective in design.…”

“…The studies included were based in different countries, including the United States, [18][19][20][21][22][23][24][25][26][27][28][29][30] Switzerland, 31 Japan, 32,33 and Germany. 26,34 All included studies [18][19][20][22][23][24][25][26]31,32,34,35 except five 21,30,33 were prospective in design. Of the included studies, only three studies 22,33,34 were published before 2015.…”

Protective and positioning devices in maxillofacial prosthodontics and radiotherapy: Overview

“…Tongue depressing devices are commonly used in unilateral radiation therapy to the neck to reduce unnecessary doses to adjacent non-target structures [22] . They help to depress the tongue, position the mandible and prevent exposure of the parotid glands.…”

Development of a customisable 3D-printed intra-oral stent for head-and-neck radiotherapy

“…Widely used methods for fabricating intra-oral stents for radiotherapy have involved either in-house fabrication using materials with questionable mechanical stability such as wax [12] , [13] or reliance on multiple dentistry appointments for design and fitting of more sophisticated patient-specific stents fabricated from resins [14] , [15] , [16] . Published commercial solutions have been limited to generic tongue depressors and mouth-opening wedges [17] .…”