Adult head and neck rhabdomyosarcoma (HNRMS) is an exceptionally rare malignancy, and there is a paucity of data and research dedicated to understanding its characteristics and management in adult populations. This study aimed to assess the outcomes and identify survival predictors in adult HNRMS. We retrospectively evaluated 42 adult patients (> 16 years) with HNRMS who received radiotherapy (RT)-based treatment at our institute between 2008 and 2022. We analysed the clinical characteristics and prognosis of these patients, including the locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS), using the Kaplan–Meier method. The chi-square and Fisher’s exact tests were used to analyse differences between groups for dichotomous and categorical variables, respectively. Survival rates were calculated using the Kaplan–Meier method. Prognostic variables were assessed through univariate Cox analyses. The median patient age was 28 years (range, 16–82 years). Alveolar RMS was the most common histological type, observed in 21 patients (50.0%), followed by embryonal in 16 patients (38.1%). The anatomic sites of origin were orbital in one (2.4%), parameningeal in 26 (61.9%), and non-orbital/non-parameningeal in 15 (35.7%) patients. Nineteen patients (45.2%) had regional lymph node metastasis, and five patients (11.9%) presented with distant metastatic disease. Distant metastasis (n = 17) was the primary cause of treatment failure. At a median follow-up of 47.0 months, the 5-year LRFS, PFS, and OS rates were 69.0%, 39.7%, and 41.0%, respectively. Univariate analysis revealed that tumour size, lymph node involvement, and the local treatment pattern (surgery and RT vs. RT alone) were significant predictors of survival. The main failure pattern in patients with HNRMS receiving RT-based treatment was distant metastasis. Tumour size > 5 cm and lymph node involvement were predictors of worse LRFS. Multimodality local treatment, combining surgery and RT, is effective and provides survival benefits.

中文翻译：

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成人头颈横纹肌肉瘤：基于放射治疗的治疗、结果和生存预测因素

成人头颈横纹肌肉瘤 (HNRMS) 是一种极其罕见的恶性肿瘤，致力于了解其特征和成人治疗的数据和研究很少。本研究旨在评估成人 HNRMS 的结果并确定生存预测因子。我们回顾性评估了 2008 年至 2022 年间在我所接受放射治疗 (RT) 治疗的 42 名 HNRMS 成年患者（> 16 岁）。我们分析了这些患者的临床特征和预后，包括局部区域无复发生存期 (LRFS) ）、无进展生存期（PFS）和总生存期（OS），使用 Kaplan-Meier 方法。卡方检验和 Fisher 精确检验分别用于分析二分变量和分类变量的组间差异。使用Kaplan-Meier 方法计算存活率。通过单变量 Cox 分析评估预后变量。患者中位年龄为 28 岁（范围：16-82 岁）。肺泡 RMS 是最常见的组织学类型，有 21 名患者 (50.0%) 观察到，其次是胚胎型 16 名患者 (38.1%)。1 例（2.4%）患者的解剖部位为眼眶，26 例（61.9%）患者为脑膜旁，15 例（35.7%）为非眼眶/非脑膜旁。19 名患者（45.2%）出现区域淋巴结转移，5 名患者（11.9%）出现远处转移。远处转移（n = 17）是治疗失败的主要原因。中位随访 47.0 个月时，5 年 LRFS、PFS 和 OS 率分别为 69.0%、39.7% 和 41.0%。单变量分析显示，肿瘤大小、淋巴结受累和局部治疗模式（手术加放疗与单纯放疗）是生存的重要预测因素。接受基于放疗的 HNRMS 患者的主要失败模式是远处转移。肿瘤大小 > 5 cm 和淋巴结受累是 LRFS 较差的预测因素。结合手术和放疗的多模式局部治疗是有效的，并能带来生存益处。