a Department of Head and Neck Clinical Oncology , The Christie NHS Foundation Trust , Manchester , UK.
b Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Heath , University of Manchester, Manchester Academic Health Science Centre , Manchester , UK.
Acta Oncol. 2018 Aug;57(8):1038-1042. doi: 10.1080/0284186X.2018.1459047. Epub 2018 Apr 9.
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.
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.
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.
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.
本可行性研究旨在确定咀嚼肌整体照射或单独亚单位照射剂量与放疗后牙关紧闭变化之间的关系。
从一个中心前瞻性招募了 20 名患者，作为比较主动锻炼治疗牙关紧闭的随机试验的一部分。III/IV 期口腔或口咽鳞癌患者接受调强放疗联合全身治疗。所有患者在放疗前均有牙关紧闭。在放疗开始前和 6 个月测量最大切牙间距离（MID）。在 CT 图像上勾画双侧咀嚼肌：翼内肌（MP 和 LP）、咬肌（M）、颞肌（T）、颞下颌关节（TMJ）。该块包括眶底以下除 TMJ 以外的所有肌肉。比较平均剂量、等效均匀剂量（EUD）和 35-60Gy（V35-V60Gy）与 MID 的变化。
在 6 个月时，6 名患者的 MID 较放疗开始时恶化，而 14 名患者的 MID 改善。年龄、性别、吸烟、饮酒状况、运动依从性、顺铂、肿瘤部位、分期、V35-V60Gy 或 EUD 与 MID 的变化之间无显著相关性。排除了一个临床离群值。没有离群值（n=19）时，同侧块（p=0.01）、LP（p=0.04）和 M（p<0.01）的平均剂量与 6 个月时 MID 的变化呈显著相关。所有 6 个月时牙关紧闭恶化的患者均接受了>40Gy 的平均剂量照射。
同侧块、LP 和 M 的平均辐射剂量越高，与牙关紧闭恶化的相关性越大。对于未侵犯咀嚼肌的肿瘤，将这些结构的剂量限制在≤40Gy 以内，可能会改善治疗相关的后遗症。同侧块、LP 和 M 应作为放射治疗计划中的替代回避结构进一步研究。
