(Background) Diffuse Optic Spectroscopy Imaging (DOSI) is non-invasive imaging technology that employs near-infrared (NIR) light to quantitatively characterize the hemodynamic and metabolic properties of breast cancer tumors.
(Methods) We utilized DOSI to measure baseline tumor concentrations of oxy-hemoglobin (ctO2Hb), deoxy-hemoglobin (ctHHb), total hemoglobin (ctTHb), oxygen saturation (stO2), as well as water and lipid content of tumors from sixteen patients with primary breast cancer prior to neoadjuvant chemotherapy. Core-needle biopsy specimens were also collected from these patients and analyzed for Ki67, Glut-1, and Fatty acid synthese (FAS), biomarkers of cancer proliferation, glucose metabolism and fatty acid metabolism, respectively. These optic and biological biomarkers were statistically compared to each other and to overall therapy response. (Results) Ki67 score was positively correlated with baseline levels of ctO2Hb (µM) (r = 0.51, p = 0.04), ctTHb (µM) (r = 0.51, p = 0.05), and stO2 (%) (r = 0.57, p = 0.02), and negatively correlated with lipid content (%) (r = -0.52, p = 0.04). Tumors with positive Glut-1 status (n=8) showed significantly higher baseline levels of ctO2Hb (26.2±12.5 v.s 19.9±10.1, p = 0.04), ctTHb (41±13.3 v.s 27.5±11.7, p = 0.05), and stO2 (81.1±6.6 v.s 70.2±9.9, p = 0.02) and lower baseline levels of lipid (49±17.1 v.s 66.2±10.4, p = 0.03) compared to those with negative Glut-1 status (n = 8). There were no correlation between FAS and the optic properties. Five (31.3%) of 16 tumors achieved pathologic complete response (pCR) after completion of chemotherapy followed by surgery. Tumors with pCR showed higher stO2, higher Ki67 score and higher likelihood of Glut-1 expression than those with non-pCR (p = 0.009, 0.01, 0.03, respectively).
Only p-values with statistical significance were described.
(Conclusion) Higher tumoral expression levels of Ki67 and Glut-1 were correlated with higher oxygenation and lower lipid concentration and associated with a pathologic complete response to chemotherapy. Non-invasive optic properties measured using DOSI are potential surrogate markers for tumor proliferation and glucose metabolism.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-01-10.