In situ evaluation of residual breast tumor and tumor grade using medical hyperspectral imaging (MHSI)

10677 Background: MHSI is a camera-based technique providing spectral data regarding tissue chemistry for each pixel in an image. Over 30% of women suffer local recurrence after resection. Intraoperative assessment of residual tumor & tumor grade would optimize care. Methods: We studied 42 S-D rats w/ breast tumors induced by gavage of DMBA & 15 controls. Tumors were exposed & resected, intentionally leaving ∼1mm residual tumor pieces. Gross examination, histo-pathology & MHSI (total 335) were performed for tumors, tumor beds after partial and total resection & control sites. A visible light MHSI system (HyperMed,Waltham, MA) w/ 40μm resolution & algorithms based on spectral features of the surgical field were developed and implemented for this study. Gross observation at surgery represents truth, as small tumor pieces were left intentionally by the surgeon and recorded. Samples from tumor beds were collected and histopathologically analyzed. When seen, gross tumor was removed from tumor bed by the pathologist. Results: MHSI performed well at identifying tumor. The kappa statistic(κ) for gross vs MHSI (84%) is significantly higher than κ for gross vs histopathology (76%) where for the κ the estimated asymptotic standard error is 3%. MHSI associates more strongly with gross than histopathology does. 81 tissue samples were separated into histologic grade: 0 = normal, 1 = benign tumor, 2 = intraductal Ca, 3 = papillary & cribiform Ca, 4 = papillary & cribiform Ca with invasion &/or comedo Ca. The imaging team (blinded) assigned tumor grade to each MHSI image. Statistical analysis defined 3 histologic groups: 9 normal (grade 0) tissue, 18 benign & intraductal tumors (grades 1–2), 54 advanced tumors (papillary, cribiform with invasion/comedo Ca, grades 3–4). Both histopathology & MHSI identified all 9 normal samples. Of 18 samples in group 2 (benign/intraductal by histopathology), 17 were qualified as benign/intraductal by MHSI (94% sens) & 1 as advanced. Of 54 samples with adv tumors by histopathology, MHSI identified 48 (89% sens) as advanced & 6 as intraductal. Conclusions: MHSI may provide convenient intraoperative, near real-time images with useful data about residual tumor & tumor grade. Human trials are planned. [Table: see text]