Intensity-modulated proton therapy and osteoradionecrosis in oropharyngeal cancer

Abstract Purpose We compared mandibular doses and osteoradionecrosis in patients with oropharyngeal cancer after intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT). Methods and materials We identified 584 patients who received definitive radiotherapy for oropha...

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Published in:Radiotherapy and oncology 2017-06, Vol.123 (3), p.401-405
Main Authors: Zhang, Wencheng, Zhang, Xiaodong, Yang, Pei, Blanchard, Pierre, Garden, Adam S, Gunn, Brandon, Fuller, C. David, Chambers, Mark, Hutcheson, Katherine A, Ye, Rong, Lai, Stephen Y, Radwan, Mohamed Abdallah Sherif, Zhu, X. Ron, Frank, Steven J
Format: Article
Language:English
Subjects:
Adult
Aged
Female
Hematology, Oncology and Palliative Medicine
Humans
IMPT
IMRT
Male
Mandible - radiation effects
Mandibular dose
Middle Aged
Oropharyngeal cancer
Oropharyngeal Neoplasms - radiotherapy
Osteoradionecrosis
Osteoradionecrosis - etiology
Particle therapy
Proton Therapy - adverse effects
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted - methods
Radiotherapy, Intensity-Modulated - adverse effects
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Summary:Abstract Purpose We compared mandibular doses and osteoradionecrosis in patients with oropharyngeal cancer after intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT). Methods and materials We identified 584 patients who received definitive radiotherapy for oropharyngeal cancer from January 2011 through June 2014 at MD Anderson Cancer Center (534 IMRT and 50 IMPT). The dosimetric variables and osteoradionecrosis were compared with Chi-square test or Fisher’s exact test. Results Median follow-up time for all patients (534 IMRT and IMPT) was 33.8 months (33.8 months IMRT vs. 34.6 months IMPT, P = 0.854), and median time to osteoradionecrosis was 11.4 months (range 6.74–16.1 months). Mandibular doses were lower for patients treated with IMPT (minimum 0.8 vs. 7.3 Gy; mean 25.6 vs. 41.2 Gy; P < 0.001), and osteoradionecrosis rates were lower as well: 2% IMPT (1 grade 1), 7.7% IMRT (12 grade 4, 5 grade 3, 1 grade 2 and 23 grade 1). Osteoradionecrosis location depended on the primary tumor site and high-dose field in the mandible. Conclusions Osteoradionecrosis events were significantly associated with higher dose irradiation to mandibular. Use of IMPT minimized excess irradiation of the mandible and consequently reduced the risk of osteoradionecrosis for oropharyngeal cancer.
ISSN:0167-8140
1879-0887
DOI:10.1016/j.radonc.2017.05.006