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Hague C, Beasley W, Garcez K, Lee LW, McPartlin A, McWilliam A, Ryder D, Sykes AJ, Thomson D, van Herk M, West C, Slevin NJ. Prospective evaluation of relationships between radiotherapy dose to masticatory apparatus and trismus. Acta Oncol 2018; 57:1038-1042. [PMID: 29630433 DOI: 10.1080/0284186x.2018.1459047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AIMS This feasibility study aimed to identify relationships between radiation doses to the masticatory apparatus as a combined block or as individual subunits with changes in trismus following radiotherapy. MATERIAL AND METHODS Twenty patients from a single center were recruited prospectively as part of a randomized trial comparing proactive exercises in the management of trismus. Patients with stage III/IV oral cavity or oropharyngeal squamous cell cancers received intensity-modulated radiotherapy with concurrent systemic therapy. All patients had trismus prior to radiotherapy. Maximal inter-incisor distance (MID) was measured pre- and 6 months from the start of radiotherapy. Bilateral muscles of mastication: medial and lateral pterygoids (MP and LP), masseters (M), temporalis (T), temporomandibular joint (TMJ) were contoured on CT images. The block comprised all muscles excluding the TMJ below the orbital floor. Mean dose, equivalent uniform dose (EUD) and V35-V60 Gy were compared with change in MID. RESULTS In six patients, the MID deteriorated at 6 months from the start of radiotherapy compared with 14 whose MID improved. No significant association was observed between age, gender, smoking, alcohol status, exercise compliance, cisplatin, tumor site, stage, V35-V60 Gy or EUD with change in MID. A clinical outlier was excluded. Without the outlier (n = 19), a significant association was seen between mean dose and change in MID at 6 months for the ipsilateral block (p = .01), LP (p = .04) and M (p < .01). All patients where trismus deteriorated at 6 months received mean doses >40 Gy to the block. CONCLUSION Higher mean radiation doses to the ipsilateral block, LP and M were significantly associated with deterioration in trismus. Limiting dose to these structures to ≤40 Gy for tumors not invading the masticatory muscles may improve treatment-related sequelae. The ipsilateral block, LP and M should be studied further as possible alternative avoidance structures in radiotherapy treatment planning.
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Affiliation(s)
- Christina Hague
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - William Beasley
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Heath, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Kate Garcez
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - Lip W. Lee
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - Andrew McPartlin
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - Alan McWilliam
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Heath, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
- Department of Radiotherapy Related Research, The Christie NHS Foundation Trust, Manchester, UK
| | - David Ryder
- Statistics Unit, The Christie NHS Foundation Trust, Manchester, UK
| | - Andrew J. Sykes
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - David Thomson
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
| | - Marcel van Herk
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Heath, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
- Department of Radiotherapy Related Research, The Christie NHS Foundation Trust, Manchester, UK
| | - Catharine West
- Translational Radiobiology Group, Division of Cancer Sciences, Manchester Academic Health Science Centre, University of Manchester, The Christie NHS Foundation Trust, Manchester, UK
| | - Nick J. Slevin
- Department of Head and Neck Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
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