Department of Radiation Oncology, Universitätsklinikum Schleswig-Holstein Campus Kiel, Arnold-Heller-Straße 3, Haus L, 24105, Kiel, Germany.
Department of Radiotherapy and Special Oncology, Medical School Hannover, Hannover, Germany.
Strahlenther Onkol. 2023 Mar;199(3):258-267. doi: 10.1007/s00066-022-01976-5. Epub 2022 Jul 20.
For patients with large tumors palliative radiotherapy often is the only local treatment option. To prevent toxicity the administered doses are low. Dose escalation to the tumor could be an option to better smyptom control and prolong local control rates. In this prospective study we used a very pragmatic approach with a simultaneously integrated boost (SIB) to an almost geometrically defined tumor core to achieve this. The primary endpoint was to demonstrate feasibility.
Patients with solid tumors > 4 cm in diameter of different histologies were eligible in this single arm, prospective, multi-institutional clinical feasibility trial with two treatment concepts: 5 × 5 Gy with an integrated boost to the tumor core of 5 × 10 Gy or 10 × 3 Gy with a boost of 10 × 6 Gy. The objective of dose escalation in this study was to deliver a minimum dose of 150% of the prescribed dose to the gross tumor volume (GTV) tumor core and to reach a maximum of at least 200% in the tumor core.
In all, 21 patients at three study sites were recruited between January 2019 and November 2020 and were almost evenly spread (9 to 12) between the two concepts. The treated planning target volumes (PTV) averaged 389.42 cm (range 49.4-1179.6 cm). The corresponding core volumes were 72.85 cm on average (range 4.21-338.3 cm). Dose escalation to the tumor core with mean doses of 167.7-207.7% related to the nonboost prescribed isodose led to PTV mean doses of 120.5-163.3%. Treatment delivery and short-term follow-up was successful in all patients.
Palliative radiotherapy with SIB to the tumor core seems to be a feasible and well-tolerated treatment concept for large tumors. The applied high doses of up to 50 Gy in 5 fractions (or 60 Gy in 10 fractions) did not cause unexpected side effects in the 42 day follow-up period. Further research is needed for more information on efficacy and long-term toxicity.
对于大肿瘤患者，姑息性放疗通常是唯一的局部治疗选择。为了防止毒性，给予的剂量较低。对肿瘤进行剂量递增可能是一种选择，可以更好地控制症状并延长局部控制率。在这项前瞻性研究中，我们采用了一种非常实用的方法，即同时对几乎几何定义的肿瘤核心进行综合增强（SIB）来实现这一目标。主要终点是证明可行性。
这项单臂、前瞻性、多机构临床可行性试验纳入了不同组织学类型的直径>4cm 的实体瘤患者，采用两种治疗方案：5×5Gy 加肿瘤核心 5×10Gy 综合增强或 10×3Gy 加肿瘤核心 10×6Gy 增强。本研究中剂量递增的目的是向肿瘤核心的大体肿瘤体积（GTV）给予至少 150%的处方剂量，并在肿瘤核心中达到至少 200%的最大剂量。
2019 年 1 月至 2020 年 11 月，共有三个研究点的 21 名患者入组，两种方案的患者数量几乎均等（9 至 12 名）。治疗的计划靶区（PTV）平均为 389.42cm³（范围为 49.4-1179.6cm³）。相应的核心体积平均为 72.85cm³（范围为 4.21-338.3cm³）。对肿瘤核心进行剂量递增，给予 167.7-207.7%的平均剂量，与非增强的规定等剂量线相关，导致 PTV 平均剂量为 120.5-163.3%。所有患者均成功完成了治疗和短期随访。
肿瘤核心的 SIB 姑息性放疗似乎是一种可行且耐受良好的大型肿瘤治疗方案。在 42 天的随访期间，高达 50Gy（或 60Gy）的 5 次（或 10 次）分割高剂量未引起意外的副作用。需要进一步研究以获取更多关于疗效和长期毒性的信息。
