Assessment of Breast Tumor Response to Neoadjuvant Chemotherapy Using Tomographic Diffuse Optical Spectroscopy: Case Studies on Changes in Tumor Regions

Abstract

This study evaluates two methods for region-of-interest (ROI) analysis to summarize tomographic diffuse optical spectroscopic (DOS) data, aiming to differentiate between complete and partial responses in patients undergoing neoadjuvant therapy for locally advanced breast cancer. Both fixed-size and variable-size ROI (full-width-at-half-maximum) methods are considered. Adjacent and opposite breast optical scattering amplitude, power, water percentage, total levels of haemoglobin (HbT), and blood oxygen saturation are some important parameters examined. Institutional review board approval and HIPAA compliance were secured, and participants provided informed consent and received compensation. In this analysis, seven of 16 patients with complete data sets were included. Postsurgical histopathologic examination categorized patients into complete response (pCR) and partial response (pIR) groups. Significant differences (P ≤ .05) in the average normalized change in HbT were observed between pCR and pIR groups. The pCR group exhibited a mean HbT change of −64.2% ± 50.8 for fixed-size ROIs and −96.7% ± 91.8 for variable-size ROIs, while the pIR group showed mean changes of 16.9% ± 38.2 and 14.1% ± 26.7, respectively. These findings suggest that tomographic DOS can potentially provide valuable predictive information on treatment responses, which could enhance personalized patient care.