Department of Radiation Oncology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, NO.1 Shuaifuyuan Wangfujing, Dongcheng District, Beijing, People's Republic of China, 100730.
Radiat Oncol. 2019 Nov 8;14(1):196. doi: 10.1186/s13014-019-1398-6.
To compare irradiation dose to the second and third portions of duodenum (Duo2 and Duo3) with a new refined and old delineation method of para-aortic region for patients with locally advanced cervical cancer (LACC) receiving prophylactic extended-field radiotherapy (EFRT).
Twenty consecutive patients with LACC were treated with prophylactic EFRT from January 2016 to January 2017 at our institute. Two delineation methods of para-aortic region were designed for each patient, the old delineation method ensured a full coverage of aortic and inferior vena cava, while the right paracaval region above L3 was omitted from CTV in the new delineation method. Patients received a dose of 50.4Gy in 28 fractions for PCTV and a dose of 60.2Gy in 28 fractions for PGTV with volumetric-modulated arc therapy (VMRT). The dose delivered to Duo2 and Duo3 with these two delineation methods were compared.
All treatment plans achieved excellent target volume coverage with 95% of PCTV receiving 50.4Gy and 95% of PGTV receiving 60.2Gy. There was no difference between delineation methods in low dose level (V5, V10, V15, V20, V25) for Duo2 and Duo3. The V30, V35, V40, V45, V50, Dmax, Dmean and D2cc for Duo2 with the new and old delineation methods were 55.76% vs 80.54% (P = 0.009), 34.72% vs 70.91% (P < 0.001), 18.69% vs 55.46% (P < 0.001), 8.20% vs 41.49% (P < 0.001), 1.86% vs 21.60% (P < 0.001), 49.58Gy vs 52.91Gy (P = 0.002), 30.38Gy vs 39.22Gy (P = 0.001) and 37.90Gy vs 48.64Gy (P < 0.001) respectively. For Duo3, the new delineation method achieved significant advantages in V30, V35, V40, V45, V50 and Dmean over the old one (96.82% vs 99.25%, P = 0.021; 89.65% vs 97.21%, P = 0.001; 79.50% vs 93.18%, P < 0.001; 65.63% vs 82.93%, P < 0.001; 43.39% vs 65.60%, P < 0.001; 46.09Gy vs 49.24Gy, P < 0.001), no deference was observed regarding D2cc and Dmax with these two delineation methods.
With the new delineation method of para-aortic area in prophylactic EFRT, significant reduction of irradiation dose to the second and third portions of duodenum in high dose area was obtained. This may further lower the incidence of duodenal toxicity when performing prophylactic EFRT for patients with LACC.
比较局部晚期宫颈癌（LACC）患者接受预防性扩展野放疗（EFRT）时，使用新的改良和旧的腹主动脉旁区域勾画方法对十二指肠第二和第三部分（Duo2 和 Duo3）的照射剂量。
2016 年 1 月至 2017 年 1 月，我院连续收治 20 例 LACC 患者，采用预防性 EFRT。为每位患者设计了两种腹主动脉旁区域勾画方法，旧勾画方法确保主动脉和下腔静脉完全覆盖，而新勾画方法将 CTV 内的右侧旁腔静脉上段 L3 省略。患者接受 PCTV 50.4Gy/28f 和 PGTV 60.2Gy/28f 的容积调强弧形治疗（VMRT）。比较这两种勾画方法对 Duo2 和 Duo3 的剂量分布。
所有治疗计划均达到了优异的靶区覆盖，95%的 PCTV 接受 50.4Gy，95%的 PGTV 接受 60.2Gy。在 Duo2 和 Duo3 的低剂量水平（V5、V10、V15、V20、V25）方面，两种勾画方法无差异。Duo2 的新老勾画方法的 V30、V35、V40、V45、V50、Dmax、Dmean 和 D2cc 分别为 55.76%和 80.54%（P=0.009），34.72%和 70.91%（P<0.001），18.69%和 55.46%（P<0.001），8.20%和 41.49%（P<0.001），1.86%和 21.60%（P<0.001），49.58Gy 和 52.91Gy（P=0.002），30.38Gy 和 39.22Gy（P=0.001），37.90Gy 和 48.64Gy（P<0.001）。对于 Duo3，新的勾画方法在 V30、V35、V40、V45、V50 和 Dmean 方面明显优于旧方法（96.82%比 99.25%，P=0.021；89.65%比 97.21%，P=0.001；79.50%比 93.18%，P<0.001；65.63%比 82.93%，P<0.001；43.39%比 65.60%，P<0.001；46.09Gy 比 49.24Gy，P<0.001），两种勾画方法在 D2cc 和 Dmax 方面无差异。
在预防性 EFRT 中使用新的腹主动脉旁区域勾画方法，可显著降低十二指肠第二和第三部分在高剂量区的照射剂量。这可能进一步降低在对 LACC 患者进行预防性 EFRT 时十二指肠毒性的发生率。
