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Radiother Oncol. 2017 Jun;123(3):401-405. doi: 10.1016/j.radonc.2017.05.006. Epub 2017 May 23.

Intensity-modulated proton therapy and osteoradionecrosis in oropharyngeal cancer.

Author information

1
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Radiation Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.
2
Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA. Electronic address: xizhang@mdanderson.org.
3
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
4
Department of Head & Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, USA.
5
Department of Quantitative Research, The University of Texas MD Anderson Cancer Center, Houston, USA.
6
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Clinical Oncology and Nuclear Medicine, Faculty of Medicine, University of Alexandria, Egypt.
7
Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA.
8
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA. Electronic address: sjfrank@mdanderson.org.

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 33.8months (33.8months IMRT vs. 34.6months IMPT, P=0.854), and median time to osteoradionecrosis was 11.4months (range 6.74-16.1months). Mandibular doses were lower for patients treated with IMPT (minimum 0.8 vs. 7.3Gy; mean 25.6 vs. 41.2Gy; 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.

KEYWORDS:

IMPT; IMRT; Mandibular dose; Oropharyngeal cancer; Osteoradionecrosis; Particle therapy

PMID:
28549794
PMCID:
PMC5779856
DOI:
10.1016/j.radonc.2017.05.006
[Indexed for MEDLINE]
Free PMC Article

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