Hall Matthew D, Mittauer Kathryn E, Herrera Roberto, Von Werne Katherine, Kotecha Rupesh, Kalman Noah S, McCulloch James, Alvarez Diane, McAllister Nicole C, Doty Delia G, Rzepczynski Amy E, Deere Will, Gutierrez Alonso N, Chuong Michael D
Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, United States.
Herbert Wertheim College of Medicine, Department of Radiation Oncology, Florida International University, Miami, FL, United States.
Front Oncol. 2023 Jan 11;12:1037674. doi: 10.3389/fonc.2022.1037674. eCollection 2022.
PURPOSE/OBJECTIVES: Magnetic resonance-guided radiotherapy (MRgRT) is increasingly used in a variety of adult cancers. To date, published experience regarding the use of MRgRT in pediatric patients is limited to two case reports. We report on the use of MRgRT for pediatric patients at our institution during a four-year period and describe important considerations in the selection and application of this technology in children.
MATERIALS/METHODS: All patients treated with MRgRT since inception at our institution between 4/2018 and 4/2022 were retrospectively reviewed. We also evaluated all pediatric patients treated at our institution during the same period who received either imaging or treatment using our magnetic resonance-guided linear accelerator (MR Linac). We summarize four clinical cases where MRgRT was selected for treatment in our clinic, including disease outcomes and toxicities and describe our experience using the MR Linac for imaging before and during treatment for image fusion and tumor assessments.
Between 4/2018 and 4/2022, 535 patients received MRgRT at our center, including 405 (75.7%) with stereotactic ablative radiotherapy (SABR). During this period, 347 distinct radiotherapy courses were delivered to pediatric patients, including 217 (62.5%) with proton therapy. Four pediatric patients received MRgRT. One received SABR for lung metastasis with daily adaptive replanning and a second was treated for liver metastasis using a non-adaptive workflow. Two patients received fractionated MRgRT for an ALK-rearranged non-small cell lung cancer and neuroblastoma. No Grade 2 or higher toxicities were observed or reported during MRgRT or subsequent follow-up. Twelve patients underwent MR imaging without contrast during treatment for brain tumors to assess for tumor/cystic changes. Two patients treated with other modalities underwent MR simulation for target volume delineation and organ at risk sparing due to anatomic changes during treatment or unexpected delays in obtaining diagnostic MR appointments.
In four pediatric patients treated with MRgRT, treatment was well tolerated with no severe acute effects. At our center, most pediatric patients are treated with proton therapy, but the cases selected for MRgRT demonstrated significant organ at risk sparing compared to alternative modalities. In particular, MRgRT may provide advantages for thoracic/abdominal/pelvic targets using gated delivery and adaptive replanning, but selected patients treated with fractionated radiotherapy may also benefit MRgRT through superior organ at risk sparing.
目的/目标：磁共振引导放疗（MRgRT）在多种成人癌症中的应用日益广泛。迄今为止，关于MRgRT在儿科患者中的应用经验仅限于两篇病例报告。我们报告了本机构在四年期间对儿科患者使用MRgRT的情况，并描述了在儿童中选择和应用该技术的重要考虑因素。
材料/方法：对2018年4月至2022年4月本机构自开展MRgRT治疗以来的所有患者进行回顾性研究。我们还评估了同期在本机构接受使用磁共振引导直线加速器（MR Linac）进行成像或治疗的所有儿科患者。我们总结了本诊所选择MRgRT进行治疗的四个临床病例，包括疾病转归和毒性反应，并描述了我们在治疗前和治疗期间使用MR Linac进行成像以进行图像融合和肿瘤评估的经验。
2018年4月至2022年4月期间，本中心有535例患者接受了MRgRT治疗，其中405例（75.7%）接受了立体定向消融放疗（SABR）。在此期间，共为儿科患者提供了347个不同的放疗疗程，其中217例（62.5%）接受了质子治疗。4例儿科患者接受了MRgRT治疗。1例因肺转移接受SABR治疗并进行每日适应性重新计划，另1例因肝转移采用非适应性流程进行治疗。2例患者因ALK重排的非小细胞肺癌和神经母细胞瘤接受了分次MRgRT治疗。在MRgRT治疗期间或随后的随访中，未观察到或报告2级或更高等级的毒性反应。12例脑肿瘤患者在治疗期间接受了无对比剂的MR成像，以评估肿瘤/囊性变化。2例接受其他治疗方式的患者因治疗期间的解剖结构变化或获取诊断性MR检查的意外延迟，接受了MR模拟以勾画靶区体积并保护危及器官。
在4例接受MRgRT治疗的儿科患者中，治疗耐受性良好，无严重急性效应。在本中心，大多数儿科患者接受质子治疗，但选择接受MRgRT治疗的病例与其他治疗方式相比，在保护危及器官方面表现出显著优势。特别是，MRgRT在使用门控递送和适应性重新计划治疗胸部/腹部/盆腔靶区时可能具有优势，但接受分次放疗的特定患者也可能通过更好地保护危及器官而从MRgRT中获益。
