Proton therapy for non-squamous cell carcinoma of the head and neck: planning comparison and toxicity

Abstract

To investigate optimal treatment planning using proton beams for non-squamous cell carcinoma of the head and neck (NSCHN), the dose distributions of plans involving pencil beam scanning (PBS) with or without a patient-specific aperture system (PSAS), passive-scattering proton therapy (PSPT) and X-ray intensity-modulated radiotherapy (IMRT) were compared. As clinical results, toxicities of PBS with PSAS, including changes in quality of life, were reported. Between April 2014 and August 2016, a total of 30 patients were treated using PBS with PSAS. In 20 patients selected at random, the dose distributions of PBS with or without the PSAS, PSPT and IMRT plans were compared. Neutron exposure by proton therapy was calculated using a Monte Carlo simulation. Toxicities were scored according to CTCAE ver. 4.0. Patients completed EORTC quality of life survey forms (QLQ-C30 and QLQ-HN35) before and 0–12 months after proton therapy. The 95% conformity number of PBS with the PSAS plan was the best, and significant differences were detected among the four plans (P < 0.05, Bonferroni tests). Neutron generation by PSAS was ~1.1-fold higher, but was within an acceptable level. No grade 3 or higher acute dermatitis was observed. Pain, appetite loss and increased weight loss were more likely at the end of treatment, but recovered by the 3 month follow-up and returned to the pretreatment level at the 12 month follow-up. PBS with PSAS reduced the penumbra and improved dose conformity in the planning target volume. PBS with PSAS was tolerated well for NSCHN.

FLASH Proton Pencil Beam Scanning Irradiation Minimizes Radiation-Induced Leg Contracture and Skin Toxicity in Mice

“…In most clinical scenarios, skin and muscle are inevitable organs at risk for any type of radiotherapy. Despite this improvement of normal tissue toxicity by PT, complications are therefore still observed during the course of patient treatment, for the most part causing skin and soft tissue damage [ 1 , 2 , 3 , 4 , 5 ].…”

Passively Scattered Proton Therapy for Nonmelanoma Skin Cancer with Clinical Perineural Invasion

“…In our experience, pencil beam scanning (PBS) is a more conformal form of proton therapy than passively scattered techniques. Iwata et al [ 19 ] have recently shown that when treating head and neck cancer, PBS compared to passively scattered proton therapy improved the conformality index, conformality number, and homogeneity index. On average, PBS also provided lower doses to the brain, eye, optic nerves, and optic chiasm.…”

Spot Scanning Proton Therapy for Sinonasal Malignant Tumors

“…This device could help to improve the dose distribution, especially in shallow regions. We previously reported the dosimetric advantages and positive effects on toxicities in patients with head and neck tumors [ 26 , 27 ]. In addition, intervention by an otolaryngological and dental team from the beginning through to post-PT may have contributed to reducing toxicities.…”

“…Additionally, we implemented a patient-specific aperture system (PSAS) with attached energy absorber and collimator to reduce the lateral penumbra and improve the dose distribution. This system was previously reported in detail [ 26 , 27 ].…”