Radiation-induced trismus in the ARTSCAN head and neck trial

Abstract

Trismus, a well-known sequelae after treatment of head and neck cancer, decreases a patient's oral function and quality of life. The main objectives of this study were to: 1) investigate the long-term prevalence of radiation-induced trismus in patients treated for head and neck cancer according to two different fractionation schedules; and 2) model a dose-response relationship for trismus. Material and methods. Patients were recruited from the Swedish ARTSCAN trial, a prospective randomised multicentre study comparing conventional and accelerated fractionation. A total of 124 patients agreed to a clinical ENT examination 21-127 months (median 66 months) after beginning radiation therapy. Trismus-related scores were assessed using the EORTC H&N35 Quality of Life questionnaire. The TheraBite ® range of motion scale was used to measure maximal interincisal distance. The dose-response relationship for structures important for mastication and the temporomandibular joints was investigated by normal tissue complication probability modelling. results. No significant differences in patient-reported trismus or maximal interincisal distance were found between the two trial arms. Patient-reported moderate to high scores regarding trismus increased from 3% at the start of radiation therapy to 25% at the long-term follow-up. Maximal interincisal distance correlated significantly with patient-reported scores of trismus. The best dose-response fit to the endpoint data was found for the dose to the ipsilateral masseter. conclusions. Trismus is a persistent complication after radiotherapy with 3D-conformal radiation therapy. We found no difference between the severity and prevalence of trismus between conventional and accelerated fractionation, but a significant correlation between the absorbed dose to the mastication structures and opening of the mouth. Further prospective studies may determine whether a reduced dose to structures important for mastication using intensitymodulated radiation therapy will reduce problems with trismus.

Limitation of mouth opening after radiotherapy for head and neck

“…In this study, the adjunctive treatments, such as chemotherapy and surgery, had no influence on the mouth opening of the volunteers, just as with the study by Lindblom et al 13 which showed no connection between surgery and mouth opening limitations. With regard to chemotherapy, Bragante et al 9 noted no variation in mouth opening measurements.…”

Risk structures for radiation-induced trismus in head and neck cancer

“…Possible confounding factors, such as dose from brachytherapy, were accounted for in our analyses and predicted trismus rates by our models were in corresponded well with the observed rates. In line with others, we based our analyses on mean absorbed structure doses as this dose metric have been reported suitable to describe relationships between various mastication structures and trismus [7][8][9][10][11]. Acknowledging that DVH points typically are strongly correlated, it is not likely that investigating other dose or volume metrics for our purpose of identifying critical structures for radiation-induced trismus would have altered the presented results substantially.…”

“…Other studies have also suggested that dose to the masseter is associated with a higher risk of trismus [8,9,11]. In particular, both Lindblom et al [8] and, and more recently, Rao et al [9] found dose to the ipsilateral masseter muscle to provide superior statistics in predicting trismus (defined by Risk structures receiving substantial dose from brachytherapy (more than a maximum absorbed doses of 3.0 Gy or more than mean absorbed doses of 2.0 Gy) were excluded from analysis of that specific structure. MIO 35 mm and CTCAE grade !1, respectively) than dose to other investigated structures (pterygoids (both), TMJ (13), and temporalis (9)).…”

“…Irradiation of the temporomandibular joint (TM joint) and muscles of mastication, especially doses to the masseter and the pterygoid muscles, have been reported to be associated with radiation-induced trismus [7][8][9][10][11]. However, available data diverge as to which anatomical structure is more critical for trismus after RT in HNC.…”

NTCP reduction for advanced head and neck cancer patients using proton therapy for complete or sequential boost treatment versus photon therapy

“…Biological evaluation was done for several clinical endpoints based on modern NTCP models with both, underlying patient characteristics and treatment procedures similar to the presented study: Incidence of acute oral mucositis (grade Ն 3) [9], aspiration assessed by videofl uoroscopy [10], xerostomia 12 months after therapy [11], subjective and objective swallowing dysfunction [12], late larynx edema (grade Ն 2) [13] and trismus assessed as jaw-opening Ͻ 35 mm [14], cf. Jakobi et al [5] for details.…”