Yoshida Ryoji, Lin Riu, Yamana Keisuke, Obayashi Takeshi, Takeshita Hisashi, Shinohara Kosuke, Kawahara Kenta, Hirayama Masatoshi, Takahashi Nozomu, Hirosue Akiyuki, Shinohara Masanori, Nakayama Hideki
Department of Oral and Maxillofacial Surgery, Faculty of Life Sciences, Kumamoto University, Honjo 1-1-1, Chuo-Ku, Kumamoto, 860-8556, Japan.
Division of Oral and Maxillofacial Surgery, Minamata City General Hospital & Medical Center, Minamata, Japan.
Int J Clin Oncol. 2025 Jul 11. doi: 10.1007/s10147-025-02821-2.
Squamous cell carcinoma of the buccal mucosa (SCCBM) is a prevalent malignancy of the oral cavity with high morbidity and mortality rates. The pterygomandibular raphe (PMR) connects the oral cavity, pharynx, and masticator space, serving as a key anatomical landmark during surgical resection. However, PMR invasion into SCCBM remains poorly understood. This study assessed the prognostic significance of PMR invasion in patients with resectable SCCBM.
The study included 82 patients with SCCBM, excluding those with T4b, who underwent radical resection at Kumamoto University Hospital between 2000 and 2017. Patients were categorized into three groups based on PMR invasion patterns: non-contact, contact, and invasion. The relationship between PMR invasion and clinicopathological characteristics was analyzed using the Fisher's exact test. The Kaplan-Meier method, log-rank test, and propensity score-matched analyses were used for survival analysis.
Contact or invasion into the PMR was significantly associated with advanced clinical T and N stages, clinical stage, endophytic growth pattern, high-grade invasion pattern, and poor tumor differentiation. Patients with PMR invasion had a higher proportion of recurrences in the buccal subcutaneous, mandibular, and masticator spaces. Univariate analysis indicated that contact- or invasion-type PMR invasion predicted worse overall survival (OS). The impact of PMR invasion on OS was confirmed using a propensity score-matched analysis.
This study revealed that PMR invasion is a potential novel grading and prognostic factor for resectable SCCBM, with significance in planning the extent of SCCBM resection.
颊黏膜鳞状细胞癌（SCCBM）是口腔中一种常见的恶性肿瘤，发病率和死亡率都很高。翼下颌缝（PMR）连接口腔、咽和咀嚼肌间隙，是手术切除过程中的关键解剖标志。然而，PMR侵犯SCCBM的情况仍知之甚少。本研究评估了PMR侵犯对可切除SCCBM患者的预后意义。
该研究纳入了82例SCCBM患者，排除了2000年至2017年在熊本大学医院接受根治性切除的T4b患者。根据PMR侵犯模式将患者分为三组：非接触型、接触型和侵犯型。采用Fisher精确检验分析PMR侵犯与临床病理特征之间的关系。采用Kaplan-Meier法、对数秩检验和倾向评分匹配分析进行生存分析。
接触或侵犯PMR与临床T和N分期晚期、临床分期、内生性生长模式、高级别侵犯模式以及肿瘤低分化显著相关。PMR侵犯的患者在颊皮下、下颌和咀嚼肌间隙的复发比例更高。单因素分析表明，接触型或侵犯型PMR侵犯预示着总体生存率（OS）更差。采用倾向评分匹配分析证实了PMR侵犯对OS的影响。
本研究表明，PMR侵犯是可切除SCCBM潜在的新分级和预后因素，对规划SCCBM切除范围具有重要意义。
