Department of Radiation Oncology, Washington University School of Medicine, St. Louis, United States.
Department of Radiation Oncology, Washington University School of Medicine, St. Louis, United States.
Radiother Oncol. 2018 Mar;126(3):519-526. doi: 10.1016/j.radonc.2017.11.032. Epub 2017 Dec 23.
PURPOSE/OBJECTIVES: SBRT is used to treat oligometastatic or unresectable primary abdominal malignancies, although ablative dose delivery is limited by proximity of organs-at-risk (OAR). Stereotactic, magnetic resonance (MR)-guided online-adaptive radiotherapy (SMART) may improve SBRT's therapeutic ratio. This prospective Phase I trial assessed feasibility and potential advantages of SMART to treat abdominal malignancies.
MATERIALS/METHODS: Twenty patients with oligometastatic or unresectable primary liver (n = 10) and non-liver (n = 10) abdominal malignancies underwent SMART. Initial plans prescribed 50 Gy/5 fractions (BED 100 Gy) with goal 95% PTV coverage by 95% of prescription, subject to hard OAR constraints. Daily real-time online-adaptive plans were created as needed, based on daily setup MR-image-set tumor/OAR "anatomy-of-the-day" to preserve hard OAR constraints, escalate PTV dose, or both. Treatment times, patient outcomes, and dosimetric comparisons between initial and adaptive plans were prospectively recorded.
Online adaptive plans were created at time of treatment for 81/97 fractions, due to initial plan violation of OAR constraints (61/97) or observed opportunity for PTV dose escalation (20/97). Plan adaptation increased PTV coverage in 64/97 fractions. Zero Grade ≥ 3 acute (<6 months) treatment-related toxicities were observed.
SMART is clinically deliverable and safe, allowing PTV dose escalation and/or simultaneous OAR sparing compared to non-adaptive abdominal SBRT.
SBRT 用于治疗寡转移或不可切除的原发性腹部恶性肿瘤，尽管消融剂量的传递受到危及器官（OAR）接近的限制。立体定向、磁共振（MR）引导在线自适应放疗（SMART）可能会提高 SBRT 的治疗比。本前瞻性 I 期试验评估了 SMART 治疗腹部恶性肿瘤的可行性和潜在优势。
材料/方法：20 例寡转移或不可切除的原发性肝（n=10）和非肝（n=10）腹部恶性肿瘤患者接受了 SMART 治疗。初始计划规定 50Gy/5 个剂量（BED100Gy），目标是 95%的 PTV 覆盖率达到处方的 95%，同时满足硬 OAR 限制。根据每天的 MR 图像设置肿瘤/OAR 的“每日解剖”，必要时每天实时创建在线自适应计划，以保持硬 OAR 限制，提高 PTV 剂量，或两者兼而有之。前瞻性记录了治疗时间、患者结局以及初始计划和自适应计划之间的剂量学比较。
由于初始计划违反了 OAR 限制（61/97）或观察到 PTV 剂量升级的机会（20/97），81/97 个分次在治疗时创建了在线自适应计划。计划适应提高了 64/97 个分次的 PTV 覆盖率。观察到零级≥3 级急性（<6 个月）与治疗相关的毒性。
与非自适应腹部 SBRT 相比，SMART 具有临床可操作性和安全性，允许 PTV 剂量升级和/或同时保护 OAR。
