Changes in Diffuse Optical Tomography Images During Early Stages of Neoadjuvant Chemotherapy Correlate with Tumor Response in Different Breast Cancer Subtypes.

Purpose: This study's primary objective was to evaluate the changes in optically derived parameters acquired with a diffuse optical tomography breast imaging system (DOTBIS) in the tumor volume of patients with breast carcinoma receiving neoadjuvant chemotherapy (NAC).

Experimental Design: In this analysis of 105 patients with stage II-III breast cancer, normalized mean values of total hemoglobin ([Formula: see text]), oxyhemoglobin ([Formula: see text]), deoxy-hemoglobin concentration ([Formula: see text]), water, and oxygen saturation ([Formula: see text]) percentages were collected at different timepoints during NAC and compared with baseline measurements. This report compared changes in these optical biomarkers measured in patients who did not achieve a pathologic complete response (non-pCR) and those with a pCR. Differences regarding molecular subtypes were included for hormone receptor-positive and HER2-negative, HER2-positive, and triple-negative breast cancer.

Results: At baseline, [Formula: see text] was higher for pCR tumors (3.97 ± 2.29) compared with non-pCR tumors (3.00 ± 1.72; = 0.031). At the earliest imaging point after starting therapy, the mean change of [Formula: see text] compared with baseline ([Formula: see text]) was statistically significantly higher in non-pCR (1.23 ± 0.67) than in those with a pCR (0.87 ± 0.61; < 0.0005), and significantly correlated to residual cancer burden classification ( = 0.448; < 0.0005). [Formula: see text] combined with HER2 status was proposed as a two-predictor logistic model, with AUC = 0.891; < 0.0005; and 95% confidence interval, 0.812-0.969.

Conclusions: This study demonstrates that DOTBIS measured features change over time according to tumor pCR status and may predict early in the NAC treatment course whether a patient is responding to NAC.