Background: This study aims to assess the benefit of a deep inspiration breath hold (DIBH) over the standard irradiation technique, and eventually to identify anatomical and/or treatment preplanning characteristics correlated with the LAD dose. Methods: Patients with left-sided breast cancer undergoing whole breast radiotherapy with DIBH were analyzed. All patients included in the analysis had plans in DIBH and free-breathing (FB). Receiving operating characteristics (ROC analysis) were used to identify the cut-off point of parameters to predict the LAD maximum dose > 10 Gy and LAD mean dose > 4 Gy, and the areas under the curve (AUCs) were computed. Post-test probability has been performed to evaluate the effect of parameters’ combination. Results: One hundred ninety-seven patients were analyzed. The LAD dose was significantly reduced in DIBH plans with the maximum and mean dose reduced by 31.7% (mean value 3.5 Gy vs. 4.8 Gy,p≤ 0.001) and 28.1% (mean value 8.2 Gy vs. 12.8 Gy,p≤ 0.001) in DIBH plans compared to FB plans. The strongest predictor of the LAD dose (maximum > 10 Gy and mean > 4 Gy) was the minimum distance of LAD from tangent open fields. Other parameters were lung volume and heart volume (LAD Dmax > 10 Gy) and lung volume, heart volume, and breast separation (LAD Dmean > 4 Gy). Conclusion: The dosimetric advantage of DIBH is clear in all patients and DIBH should always be preferred.
背景：本研究旨在评估深吸气屏气（DIBH）相较于标准放疗技术的优势，并最终确定与左前降支（LAD）剂量相关的解剖学和/或治疗计划前特征。方法：对接受全乳放疗并采用DIBH技术的左侧乳腺癌患者进行分析。所有纳入分析的患者均制定了DIBH和自由呼吸（FB）两种计划。采用受试者工作特征（ROC分析）确定预测LAD最大剂量>10 Gy和平均剂量>4 Gy的参数截断点，并计算曲线下面积（AUC）。通过后验概率评估参数组合的效果。结果：共分析了197例患者。与FB计划相比，DIBH计划中LAD剂量显著降低，最大剂量和平均剂量分别降低了31.7%（平均值3.5 Gy对比4.8 Gy，p≤0.001）和28.1%（平均值8.2 Gy对比12.8 Gy，p≤0.001）。预测LAD剂量（最大剂量>10 Gy和平均剂量>4 Gy）的最强指标是LAD与切线开放野的最小距离。其他相关参数包括肺体积和心脏体积（LAD最大剂量>10 Gy），以及肺体积、心脏体积和乳房间距（LAD平均剂量>4 Gy）。结论：DIBH的剂量学优势在所有患者中均明确显现，应优先考虑采用DIBH技术。
Preventing Cardiotoxicity in Personalized Breast Irradiation
肿瘤(癌症)患者之家