Behzadi Sophie T, Moser Rebecca, Düsberg Mathias, Aigner Maximilian, Nano Jana, Kiesl Sophia, Lammert Jacqueline, Klein Evelyn, Schmidt Georg P, Kiechle Marion, Huber Thomas, Corradini Stefanie, Combs Stephanie E, Borm Kai J
Department of Radiation Oncology, TUM School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.
Department of Gynecology, TUM School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.
Breast. 2025 Aug;82:104523. doi: 10.1016/j.breast.2025.104523. Epub 2025 Jun 25.
Sentinel lymph node biopsy (SLNB) can be safely omitted in selected early-stage, clinically node-negative breast cancer (BC) patients. While these patients are also candidates for partial breast irradiation (PBI), the dosimetric effects of PBI on the sentinel lymph node region (SLNs) and axillary levels remain unclear.
In this study, SLNs were identified and contoured in 100 BC patients using pre- and postoperative imaging. Axillary levels were contoured following ESTRO guidelines. Dose distribution to the SLN (n = 9000 data points) and axillary levels (n = 270 data points) were analyzed for whole breast irradiation (WBI) and PBI across different techniques (3D-conformal radiation therapy [3D-CRT] vs. volumetric modulated arc therapy [VMAT]), deep inspiration breath-hold [DIBH] vs. free breathing [FB]), and anatomical variations (breast size, tumor site, and upper breast border).
WBI provided full therapeutic dose coverage (>95 % of the prescribed dose) to 65 % of SLNs, compared to only 10 % (3D-CRT) and 3 % (VMAT) with PBI. DIBH significantly reduced dose distribution to SLN and axillary levels compared to FB. Lower incidental dose coverage was also observed in patients with medial/central tumors, smaller breasts, and lower upper breast borders.
These results demonstrate that PBI delivers substantially lower incidental dose to the SLN than WBI. Since patients in the INSEMA and SOUND trials were predominantly treated with WBI, combining SLNB omission with PBI should not be considered a standard approach and warrants further investigation.
对于部分早期、临床腋窝淋巴结阴性的乳腺癌（BC）患者，可以安全地省略前哨淋巴结活检（SLNB）。虽然这些患者也是部分乳腺照射（PBI）的候选者，但PBI对前哨淋巴结区域（SLNs）和腋窝各级淋巴结的剂量学影响仍不清楚。
在本研究中，通过术前和术后成像在100例BC患者中识别并勾勒出SLNs。按照欧洲放射肿瘤学会（ESTRO）指南勾勒腋窝各级淋巴结。分析了不同技术（三维适形放射治疗[3D-CRT]与容积调强弧形治疗[VMAT]）、深吸气屏气[DIBH]与自由呼吸[FB]）以及解剖变异（乳房大小、肿瘤部位和乳房上缘）情况下，全乳照射（WBI）和PBI对SLN（n = 9000个数据点）和腋窝各级淋巴结（n = 270个数据点）的剂量分布。
WBI能为65%的SLNs提供全治疗剂量覆盖（>规定剂量的95%），相比之下，PBI采用3D-CRT时为10%，采用VMAT时为3%。与FB相比，DIBH显著降低了SLN和腋窝各级淋巴结的剂量分布。在内侧/中央肿瘤、乳房较小和乳房上缘较低的患者中也观察到较低的附带剂量覆盖。
这些结果表明，PBI对SLN的附带剂量远低于WBI。由于INSEMA和SOUND试验中的患者主要接受WBI治疗，将省略SLNB与PBI联合应用不应被视为标准方法，值得进一步研究。
