基于MR加速器的MR引导放疗在食管癌患者中的临床应用

Clinical application of MR-guided radiotherapy based on MR-linac in esophageal cancer patients

目的初步探讨基于MR加速器的MR引导放疗在食管癌中的应用流程、疗效及安全性。方法回顾性分析2021年9月至2022年7月于山东省肿瘤防治研究院应用MR加速器治疗的食管癌患者的临床数据,探讨食管癌应用MR加速器的治疗流程,分析患者的疗效及安全性。全组患者均接受MR引导放疗,接受CT和MR定位、靶区勾画、Monaco治疗计划系统计划设计,MR加速器下摆位并调整计划。全组患者中位分割次数25次,计划靶体积中位单次剂量1.8 Gy,中位总剂量50.2 Gy,中位随访时长为16个月。结果全组12例患者包括颈部食管癌1例,胸上段食管癌3例,胸中段食管癌4例,胸下段食管癌4例。其中新辅助放疗3例,根治性放疗9例。所有患者治疗过程顺利,分次中位治疗时长为33 min,依从性良好。根治性放疗患者放疗后1个月客观有效例数为3例,疾病控制例数为9例,放疗后6个月客观有效例数为3例,疾病控制例数为6例。新辅助放疗的患者均在2个月内接受了手术,1例患者达病理完全缓解。最常见的急性不良反应为放射性食管炎(7例)和骨髓抑制中的白细胞计数减少(8例),晚期不良反应为放射性肺炎(1例),放疗不良反应轻微,未见4级及以上不良反应。结论基于MR加速器的MR引导放疗应用于食管癌的临床治疗流程可行,疗效良好且不良反应轻微。

Objective To explore the application process,efficacy and safety of MR-guided radiotherapy based on MR-linac in esophageal cancer.Methods The clinical data of patients with esophageal cancer treated with MR-linac at Shandong Cancer Hospital and Institute from September 2021 to July 2022 were retrospectively analyzed,to investigate the treatment process of esophageal cancer with MR-linac,and to analyze the efficacy and safety of patients.All patients received MR-guided radiotherapy,underwent CT and MR localization,target area delineation,and design of the Monaco treatment planning system plan.Adaptation-to-position adjustment was conducted during the pre-treatment evaluation.The median number of fractions was 25,the median single dose of planning target volume was 1.8 Gy,and the median total dose was 50.2 Gy.Median follow-up was 16 months.Results Among the 12 patients in the whole group,there were 1 case of cervical esophageal cancer,3 cases of upper thoracic esophageal cancer,4 cases of middle thoracic esophageal cancer and 4 cases of lower thoracic esophageal cancer,including 3 cases of neoadjuvant radiotherapy and 9 cases of radical radiotherapy.All patients had a smooth treatment process.The median treatment time was 33 min,and the patients had good compliance.For patients with radical radiotherapy,one month after radiotherapy,the number of objective remission cases was 3,and the number of disease-control cases was 9;six months after radiotherapy,the number of objective remission cases was 3,and the number of disease-control cases was 6.All patients treated with neoadjuvant radiotherapy underwent surgery within 2 months,and one patient achieved pathological complete remission.The most common acute adverse reactions were radiation esophagitis(7 cases)and leukopenia in bone marrow suppression(8 cases),with late-stage adverse reactions being radiation pneumonia(1 case).The adverse reactions to radiotherapy were slight,and no grade 4 or above adverse reactions were observed.Conclusion The clinical treatment process for esophageal cancer under MR-guided radiotherapy based on MR-linac is feasible,with good curative effects and mild adverse reactions.