Medical Radiation Sciences, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Western Sweden Healthcare Region, Gothenburg, Sweden.
Department of Otorhinolaryngology, Head and Neck Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Clin Oncol (R Coll Radiol). 2024 Oct;36(10):e388-e397. doi: 10.1016/j.clon.2024.07.003. Epub 2024 Jul 10.
To investigate how absorbed doses to mastication structures in modern radiotherapy (RT) technique for head and neck cancer (HNC) compared with earlier RT techniques and with published trismus tolerance doses. To compare the incidence of radiation-induced trismus by earlier and newer RT techniques.
This study investigated two HNC patient cohorts treated with RT in 2007-2012 (three-dimensional conformal radiotherapy [3DCRT] and/or intensity-modulated radiotherapy [IMRT]; n =121 [Cohort 1]) and 2017-2020 (volumetric-modulated arc therapy [VMAT]; n =124 [Cohort 2]). All patients underwent RT without mastication structure-sparing intent, had normal mouth-opening ability before RT, and were prospectively assessed. Trismus was defined as the maximal interincisal opening ≤35 mm at any follow-up (3-, 6-, and 12-months post-RT). The temporomandibular joints (TMJs), masseter, and medial/lateral pterygoid muscles were delineated on the planning CT:s. Mean doses were compared between cohorts, and evaluated with respect to published trismus tolerance doses. P values ≤ 0.05 indicated statistical significance.
Within 12 months post RT, 74/121 (61%) of patients in Cohort 1 had experienced trismus compared to 11/124 (9%) in Cohort 2. Averaged mean doses (±S.D.) for the masseter muscles were 35.2±8.3 Gy in Cohort 1 and 20.2±8.7 Gy in Cohort 2 (P <0.001). Corresponding numbers were 19.1±16.2 and 4.3±4.3 Gy for the TMJs, 53.7±10.1 and 40.2±16.8 Gy for the medial pterygoid muscles, and 29.2±18.7 and 9.2±8.4 Gy for the lateral pterygoid muscles (all P <0.001). Masseter muscle doses were below tolerance doses in 23% of patients in Cohort 1 compared with 90% in Cohort 2. The corresponding numbers were 52% and 96% for the TMJs, 8% and 36% for the medial pterygoid muscles and 72% and 100% for the lateral pterygoid muscles.
Mastication structure mean doses by more recent RT techniques were generally below proposed tolerance doses, with dose reductions of 10-20 Gy compared with earlier techniques. Modern RT without mastication-structure-sparing intent resulted in below 10% of HNC patients experiencing trismus compared with 60% treated with earlier techniques.
研究现代放射治疗（RT）技术对头颈部癌症（HNC）中咀嚼结构的吸收剂量与早期 RT 技术和已发表的张口困难耐受剂量相比如何。比较早期和较新 RT 技术引起的放射性张口困难的发生率。
本研究调查了 2007-2012 年接受 RT 治疗的 2 组 HNC 患者（三维适形放疗[3DCRT]和/或调强放疗[IMRT]；n=121[队列 1]）和 2017-2020 年接受 VMAT 治疗的 124 例患者（n=124[队列 2]）。所有患者在 RT 治疗前均无咀嚼结构保护意图，且张口能力正常，并进行了前瞻性评估。张口困难定义为任何随访时间（RT 后 3、6 和 12 个月）时最大切牙开口≤35mm。在计划 CT 上勾画颞下颌关节（TMJ）、咀嚼肌和内/外侧翼状肌。比较两组间的平均剂量，并与已发表的张口困难耐受剂量进行比较。P 值≤0.05 表示具有统计学意义。
在 RT 后 12 个月内，队列 1 中有 74/121（61%）例患者出现张口困难，而队列 2 中仅有 11/124（9%）例患者出现张口困难。队列 1 中咀嚼肌的平均剂量（±SD）为 35.2±8.3Gy，队列 2 为 20.2±8.7Gy（P<0.001）。TMJ 对应的数值为 19.1±16.2 和 4.3±4.3Gy，内侧翼状肌为 53.7±10.1 和 40.2±16.8Gy，外侧翼状肌为 29.2±18.7 和 9.2±8.4Gy（均 P<0.001）。队列 1 中有 23%的患者咀嚼肌剂量低于耐受剂量，而队列 2 中有 90%的患者咀嚼肌剂量低于耐受剂量。TMJ 对应的数值为 52%和 96%，内侧翼状肌为 8%和 36%，外侧翼状肌为 72%和 100%。
与早期技术相比，最近的 RT 技术对咀嚼结构的平均剂量通常低于建议的耐受剂量，降低了 10-20Gy。现代 RT 治疗无咀嚼结构保护意图，与早期技术相比，接受治疗的 HNC 患者中仅有 10%以下出现张口困难。
