a Department of Oncology , Oslo University Hospital , Oslo , Norway.
b Department of Medical Physics , Oslo University Hospital , Oslo , Norway.
Acta Oncol. 2018 Dec;57(12):1693-1699. doi: 10.1080/0284186X.2018.1512753. Epub 2018 Oct 3.
For patients with recurrent or second primary disease, re-irradiation can be challenging due to overlap with previously irradiated volumes. Dose painting may be attractive for these patients, as the focus is on delivering maximal dose to areas of high tumor activity. Here, we compare dose painting by contours (DPBC) treatment plans based on F-fluorodeoxyglucose (FDG) positron emission tomography (PET) with conventional plans.
We included 10 patients with recurrent or second primary head and neck cancer (HNC) eligible for re-irradiation. Our conventional re-irradiation regimen is hyperfractionated radiotherapy 1.5 Gy twice daily over 4 weeks, giving a total dose of 60 Gy. For DPBC, we defined two prescription volumes, PV33 and PV66, corresponding to 33 and 66% of the highest FDG uptake in the tumor. The clinical target volume (CTV) prescription dose was 60 Gy, PV33; 65-67 Gy and PV66; 70-73 Gy. The DPBC plan is to be given the first 20 fractions and the conventional plan the last 20 fractions. Dose to organs at risk (OARs) were compared for DPBC and conventional treatment. By summation of the initial curative plan and the re-irradiation plan, we also evaluated differences in dose to the 2 ccm hot spot (D).
We achieved DPBC plans with adequate target coverage for all 10 patients. There were no significant differences in OAR doses between the standard plans and the DPBC plans (p=.7). Summation of the initial curative plan and the re-irradiation plan showed that the median D increased from 130 Gy (range 113-132 Gy; conventional) to 140 Gy (range 115-145 Gy; DPBC).
Our proposed DPBC could be straightforwardly implemented and all plans met the objectives. Re-irradiation of HNC with DPBC may increase tumor control without more side effects compared to conventional radiotherapy.
对于复发或第二原发疾病的患者，由于与先前照射区域重叠，再照射可能具有挑战性。对于这些患者，剂量描绘可能很有吸引力，因为重点是将最大剂量输送到高肿瘤活性区域。在这里，我们比较了基于 F-氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）的轮廓剂量描绘（DPBC）治疗计划与常规计划。
我们纳入了 10 名符合再照射条件的复发性或第二原发头颈部癌症（HNC）患者。我们的常规再照射方案是在 4 周内每天两次进行超分割放疗 1.5Gy，总剂量为 60Gy。对于 DPBC，我们定义了两个处方体积，PV33 和 PV66，分别对应于肿瘤中 FDG 摄取最高的 33%和 66%。临床靶体积（CTV）处方剂量为 60Gy，PV33；65-67Gy 和 PV66；70-73Gy。DPBC 计划给予前 20 个分数，常规计划给予后 20 个分数。比较 DPBC 和常规治疗的危及器官（OAR）剂量。通过将初始治愈计划和再照射计划相加，我们还评估了对 2ccm 热点（D）的剂量差异。
我们为所有 10 名患者实现了 DPBC 计划，目标覆盖充足。标准计划和 DPBC 计划之间的 OAR 剂量无显著差异（p=.7）。将初始治愈计划和再照射计划相加，中位数 D 从 130Gy（范围 113-132Gy；常规）增加到 140Gy（范围 115-145Gy；DPBC）。
我们提出的 DPBC 可以直接实施，所有计划均达到目标。与常规放疗相比，DPBC 再照射 HNC 可能会增加肿瘤控制而不会增加更多副作用。
