So Hyun Chung

Predicting responses to neoadjuvant chemotherapy in breast cancer: ACRIN 6691 trial of diffuse optical spectroscopic imaging

The prospective multicenter ACRIN 6691 trial was designed to evaluate whether changes from baseline to mid-therapy in a diffuse optical spectroscopic imaging (DOSI)-derived imaging endpoint, the tissue optical index (TOI), predict pathologic complete response (pCR) in women undergoing breast cancer neoadjuvant chemotherapy (NAC). DOSI instruments were constructed at the University of California, Irvine (Irvine, CA), and delivered to six institutions where 60 subjects with newly diagnosed breast tumors (at least 2 cm in the longest dimension) were enrolled over a 2-year period. Bedside DOSI images of the tissue concentrations of deoxy-hemoglobin (ctHHb), oxy-hemoglobin (ctHbO2), water (ctH2O), lipid, and TOI (ctHHb × ctH2O/lipid) were acquired on both breasts up to four times during NAC treatment: baseline, 1-week, mid-point, and completion. Of the 34 subjects (mean age 48.4 ± 10.7 years) with complete, evaluable data from both normal and tumor-containing breast, 10 (29%) achieved pCR as determined by central pathology review. The percent change in tumor-to-normal TOI ratio (%TOITN) from baseline to mid-therapy ranged from -82% to 321%, with a median of -36%. Using pCR as the reference standard and ROC curve methodology, %TOITN AUC was 0.60 (95% CI, 0.39-0.81). In the cohort of 17 patients with baseline tumor oxygen saturation (%StO2) greater than the 77% population median, %TOITN AUC improved to 0.83 (95% CI, 0.63-1.00). We conclude that the combination of baseline functional properties and dynamic optical response shows promise for clinical outcome prediction. Cancer Res; 76(20); 5933-44. ©2016 AACR.

NON-INVASIVE MEASUREMENT OF DEEP TISSUE TEMPERATURE CHANGES CAUSED BY APOPTOSIS DURING BREAST CANCER NEOADJUVANT CHEMOTHERAPY: A CASE STUDY

Treatment-induced apoptosis of cancer cells is one goal of cancer therapy. Interestingly, more heat is generated by mitochondria during apoptosis, especially the uncoupled apoptotic state,(1,2) compared to the resting state. In this case study, we explore these thermal effects by longitudinally measuring temperature variations in a breast lesion of a pathological complete responder during neadjuvant chemotherapy (NAC). Diffuse Optical Spectroscopic Imaging (DOSI) was employed to derive absolute deep tissue temperature using subtle spectral features of the water peak at 975 nm.3 A significant temperature increase was observed in time windows during the anthracycline and cyclophosphamide (AC) regimen but in not paclitaxel and bevacizumab regimen. Hemoglobin concentration changes generally did not follow temperature, suggesting that the measured temperature increases were likely due to mitochondrial uncoupling rather than a direct vascular effect. A simultaneous increase of tissue oxygen saturation with temperature was also observed, suggesting that oxidative stress also contributes to apoptosis. Although preliminary, this study indicates that longitudinal DOSI tissue temperature monitoring provides information that can improve our understanding of the mechanisms of tissue response during NAC.

Molecular imaging of water binding state and diffusion in breast cancer using diffuse optical spectroscopy and diffusion weighted MRI

Abstract. Tissue water content and molecular microenvironment can provide important intrinsic contrast for cancer imaging. In this work, we examine the relationship between water optical spectroscopic features related to binding state and magnetic resonance imaging (MRI)-measured water diffusion dynamics. Broadband diffuse optical spectroscopic imaging (DOSI) and MR images were obtained from eight patients with locally-advanced infiltrating ductal carcinomas (tumor size=5.5±3.2  cm). A DOSI-derived bound water index (BWI) was compared to the apparent diffusion coefficient (ADC) of diffusion weighted (DW) MRI. BWI and ADC were positively correlated (R=0.90, p-value=0.003) and BWI and ADC both decreased as the bulk water content increased (R=−0.81 and −0.89, respectively). BWI correlated inversely with tumor size (R=−0.85, p-value=0.008). Our results suggest underlying sensitivity differences between BWI and ADC to water in different tissue compartments (e.g., extracellular vs cellular). These data highlight the potential complementary role of DOSI and DW-MRI in providing detailed information on the molecular disposition of water in breast tumors. Because DOSI is a portable technology that can be used at the bedside, BWI may provide a low-cost measure of tissue water properties related to breast cancer biology.

Macroscopic optical physiological parameters correlate with microscopic proliferation and vessel area breast cancer signatures

IntroductionNon-invasive diffuse optical tomography (DOT) and diffuse correlation spectroscopy (DCS) can detect and characterize breast cancer and predict tumor responses to neoadjuvant chemotherapy, even in patients with radiographically dense breasts. However, the relationship between measured optical parameters and pathological biomarker information needs to be further studied to connect information from optics to traditional clinical cancer biology. Thus we investigate how optically measured physiological parameters in malignant tumors such as oxy-, deoxy-hemoglobin concentration, tissue blood oxygenation, and metabolic rate of oxygen correlate with microscopic histopathological biomarkers from the same malignant tumors, e.g., Ki67 proliferation markers, CD34 stained vasculature markers and nuclear morphology.MethodsIn this pilot study, we investigate correlations of macroscopic physiological parameters of malignant tumors measured by diffuse optical technologies with microscopic histopathological biomarkers of the same tumors, i.e., the Ki67 proliferation marker, the CD34 stained vascular properties marker, and nuclear morphology.ResultsThe tumor-to-normal relative ratio of Ki67-positive nuclei is positively correlated with DOT-measured relative tissue blood oxygen saturation (R = 0.89, p-value: 0.001), and lower tumor-to-normal deoxy-hemoglobin concentration is associated with higher expression level of Ki67 nuclei (p-value: 0.01). In a subset of the Ki67-negative group (defined by the 15 % threshold), an inverse correlation between Ki67 expression level and mammary metabolic rate of oxygen was observed (R = −0.95, p-value: 0.014). Further, CD34 stained mean-vessel-area in tumor is positively correlated with tumor-to-normal total-hemoglobin and oxy-hemoglobin concentration. Finally, we find that cell nuclei tend to have more elongated shapes in less oxygenated DOT-measured environments.ConclusionsCollectively, the pilot data are consistent with the notion that increased blood is supplied to breast cancers, and it also suggests that less conversion of oxy- to deoxy-hemoglobin occurs in more proliferative cancers. Overall, the observations corroborate expectations that macroscopic measurements of breast cancer physiology using DOT and DCS can reveal microscopic pathological properties of breast cancer and hold potential to complement pathological biomarker information.

Heterodyne frequency-domain multispectral diffuse optical tomography of breast cancer in the parallel-plane transmission geometry.

PURPOSE The authors introduce a state-of-the-art all-optical clinical diffuse optical tomography (DOT) imaging instrument which collects spatially dense, multispectral, frequency-domain breast data in the parallel-plate geometry. METHODS The instrument utilizes a CCD-based heterodyne detection scheme that permits massively parallel detection of diffuse photon density wave amplitude and phase for a large number of source-detector pairs (10(6)). The stand-alone clinical DOT instrument thus offers high spatial resolution with reduced crosstalk between absorption and scattering. Other novel features include a fringe profilometry system for breast boundary segmentation, real-time data normalization, and a patient bed design which permits both axial and sagittal breast measurements. RESULTS The authors validated the instrument using tissue simulating phantoms with two different chromophore-containing targets and one scattering target. The authors also demonstrated the instrument in a case study breast cancer patient; the reconstructed 3D image of endogenous chromophores and scattering gave tumor localization in agreement with MRI. CONCLUSIONS Imaging with a novel parallel-plate DOT breast imager that employs highly parallel, high-resolution CCD detection in the frequency-domain was demonstrated.

Characterization of Metabolic Pathways in Breast Cancer using Diffuse Optical Tomography

Diffuse Optical Tomography measured physiological parameters were compared to pathological properties of breast cancer including Ki67 expression level. The Warburg effect was observed, which indicates a metabolic pathway taken by the cancer.

Intraoperative Monitoring of Photodynamic Therapy Efficacy using Diffuse Optical Spectroscopy in Mesotheloma Patients: Focusing on the Effect of PDT-induced Hypoxia

We used Diffuse Optical Spectroscopy to measure the effect of PDT on hemoglobin concentration changes during intra-operative PDT for mesothelioma. Those with less PDT-created hypoxia had better prognosis than those with severe hypoxia.

Abstract P2-03-10: Non-invasively measured Warburg effect: Optically measured tissue oxygenation and its correlation with Ki67 proliferation

Clinically, the level of Ki67 expression is used as a biomarker for cancer proliferation. In this clinical study, we focus on malignant tumor properties and investigate the correlations between macroscopically measured Diffuse Optical Tomography (DOT) physiological parameters with the Ki67 proliferation marker. The DOT tumor-to-normal tissue parameters were previously shown to have excellent tumor sensitivity and specificity by Choe and co-workers (JBO, 14(2):024020). In order to quantify cell proliferation, the percent of Ki67-expressing nuclei (i.e., from all the nuclei in an ROI) was used to specify Ki67 expression in cancer and normal tissues. Then, the tumor-to-normal ratio of Ki67-expressing nuclei was calculated to derive “relative” Ki67 values (i.e., rKi67). For this analysis, only normal glandular tissues with Ki67 expression were used. For these determinations of rKi67, the range of the Ki67-nuclei present in cancer tissues was 0.36-23.45% (N = 8), and in normal tissues it was 0.19-7.41% (N = 8). Ki67-expression in cancer-only tissues was also compared to DOT parameters. The range of the Ki67 present in cancer used for the analysis of the cancer-only tissues was 0.36-27.77% (N = 15). Among the DOT parameters, rStO2 (relative tissue oxygenation) and rHbO2 (relative oxy-hemoglobin concentration) were highly correlated with rKi67 as shown in table 1 (Pearson correlation: 0.92, p-value: 0.001 for rStO2 and correlation: 0.93, p-value: 0.002 for rHbO2). Also, for cancer-only Ki67, rHb (relative deoxy-hemoglobin concentration) showed a weak inverse correlation with cancer Ki67%: correlation: -0.58, p-value: 0.026. We additionally tested if the Diffuse Optical Tomography parameters are significantly different in more proliferative cancer compared to the less proliferative cancer (as determined by the 15% cutoff point). For this purpose, only rHb differentiated Ki67-positive from Ki67-negative cancer, with lower values of rHb occurring for the Ki67-positive cancer (p-value: 0.018, Wilcoxon-ranked-sum test). In this correlation study, we observed that rKi67 was highly correlated with rStO2 and rHbO2. Further, the cancer-only Ki67 showed lower correlations with the relative DOT parameters. However, we found that rHb was inversely correlated with cancer-only Ki67 percent values. Additionally, rHb was lower in the Ki67-positive cancer compared to the Ki67-negative cancer (using the 15% cutoff point). Taken together, these results suggest that in more proliferative cancers, although more oxy-hemoglobin might be supplied to the cancer, the level of oxygenated-hemoglobin remains high and less oxygen is utilized for cancer metabolism (i.e., consistent with lower rHb). This finding appears to be consistent with the Warburg effect, which accounts for the fact that proliferative cells will go through glycolysis to increase biomass without using oxygen, despite sufficient presence of oxygen in the tissue environment. Overall, the results of this study corroborate expectations that macroscopic measurement of breast cancer physiology using DOT can reveal information microscopic pathological properties of breast cancer. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-10.

Early Changes in Breast Cancer Blood Flow due to Chemotherapy: Potential Predictor for Therapeutic Efficacy

Preliminary results on human subjects with breast cancer undergoing neoadjuvant chemotherapy suggest early changes in blood flow measured with diffuse correlation spectroscopy may serve as a potential predictor for therapeutic efficacy.

Abstract 4147: Non-invasive deep tissue temperature measurement during neoadjuvant chemotherapy reveals apoptosis and metabolism changes in breast cancer during therapy

Metabolism of mitochondria can be monitored by measuring thermogenic activity. A linear increase of heating rate vs. rate of oxygen utilization for NADH oxidation has been shown [Poe, Arch. Biochem. Biophy., 1967]. Moreover, the heat generation increases four-fold in the uncoupled apoptotic state compared to resting state of mitochondria, as a successful anticancer drug opens the ion channel pore or increase membrane permeability [Estabrook, 1967, Johnstone, Cell 2002]. During apoptosis, more numerous and smaller mitochondria are yielded, which might also explain increase of heat generation. In this study we explore these issues: Diffuse Optical Spectroscopy Imaging (DOSI) monitors absolute temperature of a breast with infiltrating ductal carcinoma (IDC), as well as oxy- and deoxy-hemoglobin concentration. DOSI employs low power near-infrared light to quantify tissues. The diffusion model affords quantitative determination of tissue chromophore absorption spectra by separating scattering and absorption effects. Especially, the water peak appear at 935-1000nm provides information about tissue water concentration, state and absolute temperature as shown by Chung et al [PMB 2008, 2010]. In this case study, we measured a 63 year old subject who had IDC in both breasts. She received neoadjuvant chemotherapy with two different regimens: Adriamycin+Cytoxan (AC, one and half months) and Carboplatin+Abraxane+Avastin (CAA, 3 months). The patient was measured 19 times along the course of therapy: at pre-treatment, 8 points during AC, 9 points during CAA, and after completion of the therapy. She was a pathological complete responder. All points on a spectroscopic image of the lesion breast were used for the average and standard deviation of each quantity at each time point. After some fluctuations in the early stage, the temperature was observed to increase up to 39.5±1.2°C by the last phase of AC dose, showing 4.6% increase/day. During CAA, the temperature decreased eventually at a rate of -1%/day. After completion of the therapy, the temperature changed only about -0.6% to 36.9±0.7°C. In two time windows just before the end of AC and in the middle of CAA, oxy-hemoglobin increased with the temperature. The four fold increase of temperature during AC suggests the uncoupling of mitochondria due to apoptosis, an effect which appears as both an increase of temperature and deoxy-hemoglobin concentration. Then, possible massive cell death is indicated by the decrease of temperature. During AC therapy, possible aerobic glycolysis followed metabolic increase due to apoptosis, and then massive cell death followed. Overall, although preliminary, this study suggests the potential of DOSI measured temperature and other quantitative physiological components as a non-invasive and longitudinal monitor of apoptosis process during neoadjuvant chemotherapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4147. doi:10.1158/1538-7445.AM2011-4147