Ultrasound Department, Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland.
Radiology Department II, Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland.
Med Phys. 2022 Feb;49(2):1047-1054. doi: 10.1002/mp.15428. Epub 2022 Jan 10.
Neo-adjuvant chemotherapy (NAC) is used in breast cancer before tumor surgery to reduce the size of the tumor and the risk of spreading. Monitoring the effects of NAC is important because in a number of cases the response to therapy is poor and requires a change in treatment. A new method that uses quantitative ultrasound to assess tumor response to NAC has been presented. The aim was to detect NAC unresponsive tumors at an early stage of treatment.
The method assumes that ultrasound scattering is different for responsive and nonresponsive tumors. The assessment of the NAC effects was based on the differences between the histograms of the ultrasound echo amplitude recorded from the tumor after each NAC dose and from the tissue phantom, estimated using the Kolmogorov-Smirnov statistics (KSS) and the symmetrical Kullback-Leibler divergence (KLD). After therapy, tumors were resected and histopathologically evaluated. The percentage of residual malignant cells was determined and was the basis for assessing the tumor response. The data set included ultrasound data obtained from 37 tumors. The performance of the methods was assessed by means of the area under the receiver operating characteristic curve (AUC).
For responding tumors, a decrease in the mean KLD and KSS values was observed after subsequent doses of NAC. In nonresponding tumors, the KLD was higher and did not change in subsequent NAC courses. Classification based on the KSS or KLD parameters allowed to detect tumors not responding to NAC after the first dose of the drug, with AUC equal 0.83 0.06 and 0.84 0.07, respectively. After the third dose, the AUC increased to 0.90 0.05 and 0.91 0.04, respectively.
The results indicate the potential usefulness of the proposed parameters in assessing the effectiveness of the NAC and early detection of nonresponding cases.
新辅助化疗（NAC）用于肿瘤手术前的乳腺癌，以缩小肿瘤的大小并降低扩散的风险。监测 NAC 的效果很重要，因为在许多情况下，治疗反应不佳，需要改变治疗方法。已经提出了一种使用定量超声评估 NAC 对肿瘤反应的新方法。目的是在治疗的早期阶段检测到对 NAC 无反应的肿瘤。
该方法假设超声散射对于有反应的肿瘤和无反应的肿瘤是不同的。NAC 效果的评估基于从肿瘤在每次 NAC 剂量后和从组织体模记录的超声回波幅度的直方图之间的差异，使用柯尔莫哥洛夫-斯米尔诺夫统计量（KSS）和对称的库尔贝克-莱布勒散度（KLD）进行估计。治疗后，切除肿瘤并进行组织病理学评估。确定残留恶性细胞的百分比，并以此为基础评估肿瘤反应。该数据集包括从 37 个肿瘤获得的超声数据。通过接收者操作特征曲线（AUC）下的面积来评估方法的性能。
对于有反应的肿瘤，在随后的 NAC 剂量后观察到平均 KLD 和 KSS 值降低。在无反应的肿瘤中，KLD 较高，并且在随后的 NAC 过程中没有变化。基于 KSS 或 KLD 参数的分类允许在首次给予药物后检测到对 NAC 无反应的肿瘤，AUC 分别为 0.83 0.06 和 0.84 0.07。在第三次剂量后，AUC 分别增加到 0.90 0.05 和 0.91 0.04。
这些结果表明，所提出的参数在评估 NAC 的有效性和早期检测无反应病例方面具有潜在的用途。
