  The purpose of this clinical study is to test broad spectral range (635-1060
nm) time domain diffuse optical spectroscopy in monitoring the response of
breast cancer patients to neoadjuvant chemotherapy (NAC). The broadband
operation allows us to fully analyze tissue composition in terms of hemoglobin,
water, lipids and collagen concentration, which has never been systematically
studied until now during the course of therapy. Patients are subjected to
multiple breast optical imaging sessions, each one performed at different
stages of NAC, both on tumor-bearing and contralateral healthy breast. We
correlate the optical results with conventional imaging techniques and
pathological response. Preliminary outcomes on data of 10 patients show an
average significant reduction in the concentrations of oxy-hemoglobin (-53%, p
= 0.0020), collagen (-36%, p = 0.0039) and water (-15%, p = 0.0195), and
increase in lipids (+39%, p = 0.0137) from baseline to the end of therapy in
the tumor-bearing breast of patients who responded to therapy at least
partially. With respect to scattering, the scattering amplitude, a, increases
slightly by the end of the therapy compared to the baseline, while the
scattering slope, b, shows no significant change. Some change in concentrations
of constituents was noticed also in the contralateral healthy breast, even
though it was significant only for oxy-hemoglobin concentration. Collagen seems
to be the only component distinguishing between complete (p = 0.0423) and
partial responders (p = 0.1012) by the end of 2-3 weeks after the start of
therapy, suggesting that it could serve as a potential biomarker to measure NAC
effectiveness early during treatment. These initial results are consistent with
those of standard medical modalities and highlight the sensitivity of the
technique to changes that occur in breast composition during NAC.
