Purpose: Analyzing dose distributions to regional lymph-node metastases (RLNMs) in locally advanced cervical cancer (LACC) patients undergoing intracavitary and interstitial hybrid brachytherapy (IC/IS). Methods: Dose distributions of eleven LACC patients with 38 RLNMs, and who received 38 IC/IS sessions were analyzed in EQD2, considering RLNM positions and ipsilateral interstitial needles; these RLNMs, excepting the para-aortic region, were classified into four groups. Results: RLNMs had a median of two ipsilateral interstitial needles per session. Significant differences were observed in total RLNM D90, depending on whether the position was cranial or caudal of the uterine base (85.5 vs. 378.9 cGy,p< 0.0001), and whether the RLNM D90was associated with a number of ipsilateral interstitial needles between 0–1 or 2 or more (68.4 vs. 112.2 cGy,p= 0.006) per session. At each session, Group 1 RLNMs (cranial of the uterine base, 0–1 ipsilateral interstitial needle) had a mean D90of 21.1 cGy; Group 2 (cranial, 2 or more), 73.8; Group 3 (caudal, 0–1), 94.7; and Group 4 (caudal, 2 or more), 136.1. Conclusion: RLNMs located caudal of the uterine base associated with two or more ipsilateral interstitial needles in IC/IS had a higher dose contribution, which should be considered when calculating the RLNMs’ dose of external beam boost irradiation.
目的：分析接受腔内联合组织间插植近距离放疗（IC/IS）的局部晚期宫颈癌（LACC）患者区域淋巴结转移灶（RLNMs）的剂量分布。方法：以等效生物剂量（EQD2）形式分析11例LACC患者（共38个RLNMs）接受的38次IC/IS治疗剂量分布，结合RLNMs位置与同侧插植针数量（腹主动脉旁区域除外），将RLNMs分为四组。结果：每次治疗中，每个RLNM平均对应2根同侧插植针。RLNM总D90剂量在子宫基底头侧与尾侧位置间存在显著差异（85.5 vs. 378.9 cGy, p<0.0001）；当每次治疗中同侧插植针数为0-1根与≥2根时，RLNM D90剂量亦存在显著差异（68.4 vs. 112.2 cGy, p=0.006）。各组每次治疗的RLNM平均D90剂量分别为：第1组（子宫基底头侧，0-1根插植针）21.1 cGy；第2组（头侧，≥2根）73.8 cGy；第3组（尾侧，0-1根）94.7 cGy；第4组（尾侧，≥2根）136.1 cGy。结论：在IC/IS治疗中，位于子宫基底尾侧且关联≥2根同侧插植针的RLNMs可获得更高剂量贡献，在计算外照射推量剂量时应予以考虑。
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