Abstract PS1-06-28: Non-invasive classification between benign and cancerous breast lesions via time-domain bioimpedance sensing in a first-in-human study

Abstract Introduction: Breast cancer is the most common cancer in women worldwide. While mammography remains the standard for early detection, radiation, discomfort and cost warrant development of novel screening tools and diagnostic approaches. One such approach is bioimpedance scanning, a non-invasive modality which measures electrical differences between healthy and cancerous tissue in the breast. In this study, we present a novel handheld device using time-domain bioimpedance sensing (TD-BIS) that infers dielectric properties of tissue from voltage time-series data. Analysing this data with machine learning methods, the TD-BIS technology was used to determine if lesions present in patients were either benign or cancerous in nature. Methods: 68 participants undergoing routine mammography or breast ultrasound were enrolled post radiological review and diagnosed by biopsy. Prior to the biopsy, participants were scanned on each breast using the TD-BIS device at predefined locations on the breast. Scans from 7 standard positions were recorded from each breast, starting with one taken directly on the nipple (N) and the remaining scans taken at clock-face positions 2, 4, 6, 8, 10, and 12, with the nipple at the centre. For the right breast, these positions were labelled ‘inner above (IA), 'inner below’ (IB), ‘below’ (B), ‘outer below’ (OB), ‘outer above’ (OA), and ‘above’ (A) respectively. OA/IA and OB/OB were swapped for the left breast. The range, mean, standard deviation, skewness and kurtosis for different groups of capacitances were used as input for a random forest model. Distinguishing between cancerous and benign lesion classification, the F1 score, balanced accuracy (BA), false positive rate (FPR), false negative rate (FNR), positive predictive value (PPV) and negative predictive value (NPV) were calculated. Models were trained using either one scan per patient from the above list (single scan), all scans combined (combined scans), or all scan data that was within 8 cm of the known lesion (close scans). Mann-Whitney tests (with a Bonferroni correction) were used to evaluate the significance between models. Independent t-tests were used to compare the performance of each scan position relative a random permutation of the labels. Results: 62 breasts were categorized as cancerous (n=30) or benign (n=32) via radiological and biopsy evaluation. Results showed that the most significant and best (according to BA and F1) performing models in cancer/benign distinction were ‘Close’, A, IA, IB, N, and B models. However, using only one scan position resulted in high FNR. For close scan data, 12 of 30 benign lesions and 31 of 32 cancerous lesions were correctly identified, respectively. The performance for close scans was: BA:0.651, F1:0.623, FNR:0.039, FPR:0.660, PPV:0.609, NPV:0.895, all with p-value