Abstract P6-02-02: Near-infrared spectral tomography (NIRST): A prognostic assessment tool for predicting residual cancer burden (RCB) during neoadjuvant chemotherapy (NAC) in breast cancer (BC)

Abstract

Abstract Background: NIRST, a noninvasive imaging with no ionizing radiation, has been found to be prognostic as a tool to monitor early pathologic response to NAC in BC using biophysical properties of the tumor compared with normal breast tissue. We aim to establish NIRST indicators as early surrogates of treatment response and to evaluate its potential as a predictive tool in treatment decisions. Methods: 27 women with locally advanced BC undergoing NAC were enrolled in this pilot study. NIRST imaging was performed pre-treatment, after cycle 1 and 2, at the mid-point of NAC, and at the conclusion of NAC prior to surgery. Biophysical data including oxy- and deoxy-hemoglobin, water, lipid, and scatter components were obtained at these time points. To minimize inter-subject variability due to breast density and its effects on the NIRST data, statistical analysis was conducted using ratios of obtained biophysical data to pretreatment average of the contralateral normal breast tissue. Residual Cancer Burden (RCB) index was used to evaluate residual disease after treatment with NAC. RCB scores and classes were determined in 24 of the 27 surgical tissue specimens and these were compared to the NIRST data. RCB data for 3 patients were excluded: 2 patients had undergone positive excisional lymph node biopsy prior to NAC and 1 patient had surgery at an outside hospital. Results: Of the 27 patients, 7 had triple negative BC and 13 had HER-2 positive BC. The change in total hemoglobin (ΔHb-T %) after the first cycle of NAC when compared to the pre-treatment total hemoglobin was determined to be the best predicting factor for RCB (p-value <0.001). The Pearson correlation coefficient was calculated for both RBC class and RBC score (0.7 and 0.6). The significance of the correlation coefficient was evaluated using two-sided t-test and the resulting P-values of 0.006 and 0.001 respectively demonstrate that these correlations are statistically significant. Summary of the NIRST biophysical data and the correlating RCBPatientAgeERPRHer2RCB ScoreHbT -ΔHbT-pre136+-+0-139.933.30251---0-43.532.53341+++0-42.281.89430---0-43.061.59552---0-42.541.71663+++0-151.883.12760--+0-46.471.59852---0-42.721.96966--+0-110.022.471039--+0-9.091.101171+-+0-13.331.501252++-4.12153.201.581362++-3.7475.741.531470--+1.931100.521.631553++-3.4447.831.181641+++4.18929.841.511756+++4.44459.001.471850++-4.008-41.112.181954---3.05011.111.802063++-2.90020.001.502149---0.78026.321.902257++-1.8505.881.702347++-3.600-7.692.602470---3.10047.061.70 Conclusions: We have demonstrated a statistically significant correlation between ΔHb-T % after the first cycle of NAC and the RCB. These findings suggest the potential of using NIRST as an early assessment tool to evaluate response to NAC in BC patients and warrant further evaluation in a larger study. Citation Format: Batukbhai B, Jiang S, Bernhardt EB, Muller K, Cao X, Gui J, DiFlorio-Alexander RM, Chamberlin MD, Schwartz GN, Paulsen KD, Pogue BW, Kaufman PA. Near-infrared spectral tomography (NIRST): A prognostic assessment tool for predicting residual cancer burden (RCB) during neoadjuvant chemotherapy (NAC) in breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-02.