Lee Byung Min, Chang Jee Suk, Kim Se Young, Keum Ki Chang, Suh Chang-Ok, Kim Yong Bae
Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, South Korea.
Department of Radiation Oncology, CHA Bundang Medical Center, CHA University, Bundang-gu, South Korea.
Front Oncol. 2020 Feb 11;10:124. doi: 10.3389/fonc.2020.00124. eCollection 2020.
Radiation pneumonitis (RP) is one of the most severe toxicities experienced by patients with breast cancer after radiotherapy (RT). RT fractionation schemes and techniques for breast cancer have undergone numerous changes over the past decades. This study aimed to investigate the incidence of RP as a function of such changes in patients with breast cancer undergoing RT and to identify dosimetric markers that predict the risk of this adverse event. We identified 1,847 women with breast cancer who received adjuvant RT at our institution between 2015 and 2017. The RT technique was individually tailored based on each patient's clinicopathological features. Deep inspiration breath hold technique or prone positioning were used for patients who underwent left whole-breast irradiation for cardiac sparing, while those requiring regional lymph node irradiation underwent volumetric-modulated arc therapy (VMAT). Of 1,847 patients who received RT, 21.2% received the conventional dose scheme, while 78.8% received the hypofractionated dose scheme (mostly 40 Gy in 15 fractions). The median follow-up period was 14.5 months, and the overall RP rate was 2.1%. The irradiated organ at risk was corrected concerning biologically equivalent dose. The ipsilateral lung V in equivalent dose in 2 Gy (EQD2) was the most significant dosimetric factor associated with RP development. Administering RT using VMAT, and hypofractionated dose scheme significantly reduced ipsilateral lung V. Application of new RT techniques and hypofractionated scheme significantly reduce the ipsilateral lung dose. Our data demonstrated that ipsilateral lung V in EQD2 is the most relevant dosimetric predictor of RP in patients with breast cancer.
放射性肺炎（RP）是乳腺癌患者放疗（RT）后经历的最严重毒性反应之一。在过去几十年中，乳腺癌的放疗分割方案和技术发生了诸多变化。本研究旨在调查接受放疗的乳腺癌患者中RP的发生率与这些变化的关系，并确定预测这一不良事件风险的剂量学标志物。我们确定了2015年至2017年期间在我院接受辅助放疗的1847例乳腺癌女性患者。放疗技术根据每位患者的临床病理特征进行个体化定制。对于接受左全乳照射以保护心脏的患者，采用深吸气屏气技术或俯卧位，而需要区域淋巴结照射的患者则接受容积调强弧形放疗（VMAT）。在1847例接受放疗的患者中，21.2%接受传统剂量方案，而78.8%接受大分割剂量方案（大多为40 Gy分15次）。中位随访期为14.5个月，总体RP发生率为2.1%。对受照射的危险器官进行了生物学等效剂量校正。同侧肺在2 Gy等效剂量（EQD2）下的体积是与RP发生相关的最显著剂量学因素。使用VMAT和大分割剂量方案进行放疗显著降低了同侧肺体积。新放疗技术和大分割方案的应用显著降低了同侧肺剂量。我们的数据表明，EQD2下的同侧肺体积是乳腺癌患者RP最相关的剂量学预测指标。
