Department of Radiation Oncology, Soonchunhyang University College of Medicine, Soonchunhyang University Hospital, Bucheon 14584, Republic of Korea.
Department of Surgery, Soonchunhyang University College of Medicine, Soonchunhyang University Hospital, Bucheon 14584, Republic of Korea.
Medicina (Kaunas). 2023 Jun 3;59(6):1081. doi: 10.3390/medicina59061081.
: Intensity-modulated radiation therapy (IMRT) is becoming a more common method of performing whole breast irradiation (WBI) for early breast cancer. This study aimed to examine the incidental dose to the axillary region using tomotherapy, a unique form of IMRT. : This study included 30 patients with early-stage breast cancer who underwent adjuvant WBI using TomoDirect IMRT. A hypofractionation scheme of 42.4 Gy delivered in 16 fractions was prescribed. The plan comprised of two parallel-opposed beams, along with two additional beams positioned anteriorly at gantry angles of 20° and 40° from the medial beam. The incidental dose received at axillary levels I, II, and III was evaluated using several dose-volume parameters. : The study participants had a median age of 51 years, and 60% had left-sided breast cancer. The mean dose of the axilla for levels I, II, and III were 15.5 ± 4.8 Gy, 14.9 ± 4.2 Gy, and 1.5 ± 1.6 Gy, respectively. Adequate coverage of the axilla, defined as V95%[%], was achieved for 4.7 ± 3.9%, 4.8 ± 3.7%, and 0 ± 0% for levels I, II, and III, respectively. The results were compared with those of previously published studies, and the axillary mean dose and V95%[%] of TomoDirect IMRT were low, comparable to other IMRT techniques, and lower than those of traditional tangential therapy. : While incidental axillary radiation during WBI has been proposed to assist in regional disease control, the TomoDirect plan was demonstrated to decrease this dose, and a hypofractionation scheme would further lower its biological effectiveness. Future clinical studies should incorporate dosimetrical analysis of incidental axillary dose, in order to facilitate hypofractionated IMRT planning with risk-adjusted axilla coverage in early breast cancer.
调强放疗（IMRT）在早期乳腺癌全乳照射（WBI）中越来越普遍。本研究旨在使用托姆治疗（一种独特的调强放疗形式）检查腋窝区域的意外剂量。
这项研究包括 30 名接受 TomoDirect IMRT 辅助 WBI 的早期乳腺癌患者。规定了 42.4Gy 的分割方案，共 16 次。该计划由两个平行对置的射束组成，另外还有两个射束从前侧以从内侧射束的 20°和 40°的角度定位。使用几个剂量-体积参数评估腋窝 I、II 和 III 水平的意外剂量。
研究参与者的中位年龄为 51 岁，60%为左侧乳腺癌。I、II 和 III 水平的腋窝平均剂量分别为 15.5 ± 4.8Gy、14.9 ± 4.2Gy 和 1.5 ± 1.6Gy。达到了足够的腋窝覆盖率，定义为 V95%[％]，分别为 4.7 ± 3.9%、4.8 ± 3.7%和 0 ± 0%。将结果与之前发表的研究进行比较，TomoDirect IMRT 的腋窝平均剂量和 V95%[％]较低，与其他调强放疗技术相当，低于传统切线治疗。
虽然在 WBI 期间进行意外的腋窝放疗已被提议有助于局部疾病控制，但 TomoDirect 计划证明可以降低这种剂量，并且分割方案会进一步降低其生物学效果。未来的临床研究应结合意外腋窝剂量的剂量学分析，以便在早期乳腺癌中进行风险调整的腋窝覆盖的调强放疗计划的分割。
