Decreased radiation doses to tongue with “stick-out” tongue position over neutral tongue position in head and neck cancer patients who refused or could not tolerate an intraoral device (bite-block, tongue blade, or mouthpiece) due to trismus, gag reflex, or discomfort during intensity-modulated radiation therapy

Whoon Jong Kil,Ronald Derrwaldt,Christina Kulasekere,Craig Hatch,Jacob Bugno

doi:10.18632/oncotarget.10621

Abstract

PurposeTo assess changes in oral cavity (OC) shapes and radiation doses to tongue with different tongue positions during intensity-modulated radiation therapy (IMRT) in patients with head and neck squamous cell carcinoma (HNSCC) but who refused or did not tolerate an intraoral device (IOD), such as bite block, tongue blade, or mouthpiece.ResultsTongue volume outside of OC was 7.1 ± 3.8 cm3 (5.4 ± 2.6% of entire OC and 7.8 ± 3.1% of oral tongue) in IMRT-S. Dmean of OC was 34.9 ± 8.0 Gy and 31.4 ± 8.7 Gy with IMRT-N and IMRT-S, respectively (p < 0.001). OC volume receiving ≥ 36 Gy (V36) was 40.6 ± 16.9% with IMRT-N and 33.0 ± 17.0% with IMRT-S (p < 0.001). Dmean of tongue was 38.1 ± 7.9 Gy and 32.8 ± 8.8 Gy in IMRT-N and IMRT-S, respectively (p < 0.001). V15, V30, and V45 of tongue were significantly lower in IMRT-S (85.3 ± 15.0%, 50.6 ± 16.2%, 24.3 ± 16.0%, respectively) than IMRT-N (94.4 ± 10.6%, 64.7 ± 16.2%, 34.0 ± 18.6%, respectively) (all p < 0.001). Positional offsets of tongue during the course of IMRT-S was –0.1 ± 0.2 cm, 0.01 ± 0.1 cm, and –0.1 ± 0.2 cm (vertical, longitudinal, and lateral, respectively).Materials and Methods13 patients with HNSCC underwent CT-simulations both with a neutral tongue position and a stick-out tongue for IMRT planning (IMRT-N and IMRT-S, respectively). Planning objectives were to deliver 70 Gy, 63 Gy, and 56 Gy in 35 fractions to 95% of PTVs. Radiation Therapy Oncology Group (RTOG) recommended dose constraints were applied. Data are presented as mean ± standard deviation and compared using the student t-test.ConclusionsIMRT-S for patients with HNSCC who refused or could not tolerate an IOD has significant decreased radiation dose to the tongue than IMRT-N, which may potentially reduce RT related toxicity in tongue in selected patients.

Highlights

Radiation therapy (RT) is part of the standard treatment for head and neck squamous cell carcinoma (HNSCC) together with surgery and chemotherapy [1]
Radiation dose to salivary glands and mucosa lining in oral cavity and pharynx is closely related with decreased salivary flow, oral mucositis and dysphagia, which are exacerbated by concurrent chemotherapy during RT [10, 11]
1.5 ± 0.3 cm Intensity-modulated RT (IMRT)-N: Intensity Modulated Radiation Therapy with neutral tongue position; IMRT-S: Intensity Modulated Radiation therapy with “stick-out” tongue position; p-value using t-test, Data are presented as mean ± standard deviation

Summary

Introduction

Radiation therapy (RT) is part of the standard treatment for head and neck squamous cell carcinoma (HNSCC) together with surgery and chemotherapy [1]. RT [2,3,4], treatments with RT or CCRT for patients with HNSCC frequently cause treatment related toxicities which include pain and dry mouth, taste changes, and difficulty swallowing during and after treatments [5, 6]. These treatments related toxicities in patients with HNSCC can adversely affect daily quality of life and nutritional status. Advances in RT techniques, such as salivary sparing Intensity-modulated RT (IMRT), has significantly preserved in salivary glands function in patient with HNSCC after RT [12, 13]. Pharyngeal constrictors (PC) sparing IMRT improved swallowing function after RT or CCRT for HNSCC [14, 15]

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Results

Discussion

Conclusion