56 Prospective Study of Quantitative Near-Infrared Spectroscopy for Noninvasive Assessment of Suspicious Breast Lesions

Background

A definitive breast cancer diagnosis requires biopsy. However, suspicious lesions classified BI-RADS 3 are not indicated for biopsy, leading many patients to undergo extended imaging surveillance lasting 6 to 18 months. This period of uncertainty can cause significant stress and anxiety and represents a missed opportunity for treatment if malignant. Light-based diffuse optical spectroscopy (DOS) has been investigated as a noninvasive and safe technique for breast imaging and palpable lesion assessment due to its sensitivity to tissue composition. In this prospective study, we evaluate the discriminative power of DOS for distinguishing suspicious benign and malignant breast lesions in patients undergoing biopsy.

Material and Methods

Sixty-eight women 18 years or older with at least 1 suspicious breast lesion and scheduled for biopsy were enrolled at Northern Westchester Hospital (Mt. Kisco, NY). The Northwell Health Institutional Review Board (IRB #20-0651) approved the study, and the subjects provided written informed consent. Imaging was done using a custom-made continuous-wave and frequency-domain DOS system following the procedure described in Prospective Study of Quantitative Broadband Diffuse Optical Spectroscopy for Differential Diagnosis of Suspicious Breast Lesions. Maps of tissue composition were obtained using DOS for oxyhemoglobin, deoxyhemoglobin, methemoglobin, water, lipids, and collagen. The lesion region of interest was defined as the interior points of the grid. From those, the average absolute chromophore value, average lesion-to-normal (L/N) ratio, z-score–normalized values, and malignancy probability were computed using a previously published model.

Results

Of the 68 enrolled subjects, 21 were excluded due to operator error (n = 7), instrument failure (n = 3), or insufficient signal-to-noise ratio (n = 11). Among the remaining subjects, 14 had biopsy-confirmed malignant lesions, and 33 had benign lesions. Analysis of absolute concentrations revealed that collagen was significantly elevated (P = .037) in malignant lesions compared with normal tissue, while methemoglobin approached significance (P = .058); the other 5 chromophores did not present any significant differentiating power (Figure). For the z-score data, only 36 subjects were analyzed, and water was the only significant differentiator (P = .039).

Conclusion

These results support the continued investigation of DOS as a complementary, noninvasive tool for breast cancer diagnosis. Collagen and methemoglobin showed promise as biomarkers for malignancy, consistent with prior studies. In contrast to similar reports, total hemoglobin was not significantly different between lesion types in this cohort. However, z-score normalization relative to contralateral tissue revealed water as a significant differentiator between benign and malignant lesions. Larger studies are needed to confirm these findings and refine diagnostic models. The high exclusion rate further underscores the need for improved robustness, usability, and standardization of the DOS system.