Predicting Treatment Response of Breast Cancer to Neoadjuvant Chemotherapy Using Ultrasound-Guided Diffuse Optical Tomography

PURPOSE: To prospectively investigate ultrasound-guided diffuse optical tomography (US-guided DOT) in predicting breast cancer response to neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: Eighty-eight breast cancer patients, with a total of 93 lesions, were included in our study. Pre- and post-last chemotherapy, size and total hemoglobin concentration (THC) of each lesion were measured by conventional US and US-guided DOT 1 day before biopsy (time point t0, THC THC0, SIZE S0) and 1 to 2 days before surgery (time point tL, THCL, SL). The relative changes in THC and SIZE of lesions after the first and last NAC cycles were considered as the variables Delta THC and Delta SIZE. Receiver operating characteristic curve was performed to calculate Delta THC and Delta SIZE cutoff values to evaluate pathologic response of 93 breast cancers to NAC, which were then prospectively used to predicate response of 61 breast cancers to NAC. RESULTS: The cutoff values of Delta THC and Delta SIZE for evaluation of breast cancers NAC treatment response were 23.9% and 42.6%. At Delta THC 23.9%, the predicted treatment response in 61 breast lesions for the time points t1 to t3 was calculated by area under the curve (AUC), which were AUC(1) 0.534 (P = .6668), AUC(2) 0.604 (P = .1893), and AUC(3) 0.674(P = . 0.027), respectively; for Delta SIZE 42.6%, at time points t1 to t3, AUC(1) 0.505 (P = .9121), AUC(2) 0.645 (P = .0115), and AUC(3) 0.719 (P = .0018). CONCLUSION: US-guided DOT Delta THC 23.9% and US Delta SIZE 42.6% can be used for the response evaluation and earlier prediction of the pathological response after three rounds of chemotherapy.