Lee Jeongshim, Kim Jee Hung, Liu Mitchell, Bang Andrew, Olson Robert, Chang Jee Suk
Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea.
Department of Radiation Oncology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.
J Breast Cancer. 2024 Apr;27(2):91-104. doi: 10.4048/jbc.2024.0004. Epub 2024 Mar 26.
To report on the local control and toxicity of 5-fraction, high-conformal ultrafractionated radiation therapy (RT) for primary tumors in patients with metastatic breast cancer (MBC) who did not undergo planned surgical intervention.
We retrospectively reviewed 27 patients with MBC who underwent 5-fraction high-dose ultrafractionated intensity-modulated RT for their primary tumors between 2017 and 2022 at our institution. A median dose of 66.8 Gy (range, 51.8-83.6 Gy) was prescribed to the gross tumor, calculated in 2-Gy equivalents using an α/β ratio of 3.5, along with a simultaneous integrated boost of 81.5%. The primary endpoint of this study was local control.
The median tumor size and volume were 5.1 cm and 112.4 cm, respectively. Treatment was generally well tolerated, with only 15% of the patients experiencing mild acute skin toxicity, which resolved spontaneously. The best infield response rate was 82%, with the objective response observed at a median time of 10.8 months post-RT (range, 1.4-29.2), until local progression or the last follow-up. At a median follow-up of 18.3 months, the 2-year local control rate was 77%. A higher number of prior lines of systemic therapy was significantly associated with poorer 2-year local control (one-two lines, 94% vs three or more lines, 34%; = 0.004). Post-RT, 67% of the patients transitioned to the next line of systemic therapy, and the median duration of maintaining the same systemic therapy post-RT was 16.3 months (range, 1.9-40.3).
In our small dataset, 5-fraction, high-conformal ultrahypofractionated breast RT offered promising 2-year local control with minimal toxicity. Further studies are warranted to investigate the optimal dose and role in this setting.
报告在未接受计划性手术干预的转移性乳腺癌（MBC）患者中，采用5次分割、高适形超分割放疗（RT）治疗原发性肿瘤的局部控制情况和毒性反应。
我们回顾性分析了2017年至2022年期间在我院接受5次分割高剂量超分割调强放疗治疗原发性肿瘤的27例MBC患者。给予大体肿瘤的中位剂量为66.8 Gy（范围51.8 - 83.6 Gy），使用α/β比值3.5以2-Gy等效剂量计算，同时给予81.5%的同步整合加量。本研究的主要终点是局部控制。
肿瘤的中位大小和体积分别为5.1 cm和112.4 cm³。治疗总体耐受性良好，仅15%的患者出现轻度急性皮肤毒性，且可自行缓解。最佳野内缓解率为82%，在放疗后中位10.8个月（范围1.4 - 29.2个月）观察到客观缓解，直至局部进展或最后一次随访。中位随访18.3个月时，2年局部控制率为77%。既往全身治疗线数较多与2年局部控制较差显著相关（1 - 2线，94% vs 3线或更多线，34%；P = 0.004）。放疗后，67%的患者过渡到下一线全身治疗，放疗后维持同一全身治疗的中位持续时间为16.3个月（范围1.9 - 40.3个月）。
在我们的小样本数据集中，5次分割、高适形超分割乳腺放疗提供了有前景的2年局部控制，且毒性最小。有必要进一步研究以探讨该情况下的最佳剂量和作用。
