Diagnostic Accuracy of Cross-Polarization OCT and OCT-Elastography for Differentiation of Breast Cancer Subtypes: Comparative Study

Abstract

The possibility to assess molecular-biological and morphological features of particular breast cancer types can improve the precision of resection margin detection and enable accurate determining of the tumor aggressiveness, which is important for treatment selection. To enable reliable differentiation of breast-cancer subtypes and evaluation of resection margin, without performing conventional histological procedures, here we apply cross-polarization optical coherence tomography (CP-OCT) and compare it with a novel variant of compressional optical coherence elastography (C-OCE) in terms of the diagnostic accuracy (Ac) with histological verification. The study used 70 excised breast cancer specimens with different morphological structure and molecular status (Luminal A, Luminal B, Her2/Neo+, non-luminal and triple-negative cancer). Our first aim was to formulate convenient criteria of visual assessment of CP-OCT and C-OCE images intended (i) to differentiate tumorous and non-tumorous tissues and (ii) to enable more precise differentiation among different malignant states. We identified such criteria based on the presence of heterogeneities and characteristics of signal attenuation in CP-OCT images, as well as the presence of inclusions/mosaic structures combined with visually feasible assessment of several stiffness grades in C-OCE images. Secondly, we performed a blinded reader study of the Ac of C-OCE versus CP-OCT, for delineation of tumorous versus non-tumorous tissues followed by identification of breast cancer subtypes. For tumor detection, C-OCE showed higher specificity than CP-OCT (97.5% versus 93.3%) and higher Ac (96.0 versus 92.4%). For the first time, the Ac of C-OCE and CP-OCT were evaluated for differentiation between non-invasive and invasive breast cancer (90.4% and 82.5%, respectively). Furthermore, for invasive cancers, the difference between invasive but low-aggressive and highly-aggressive subtypes can be detected. For differentiation between non-tumorous tissue and low-aggressive breast-cancer subtypes, Ac was 95.7% for C-OCE and 88.1% for CP-OCT. For differentiation between non-tumorous tissue and highly-aggressive breast cancers, Ac was found to be 98.3% for C-OCE and 97.2% for CP-OCT. In all cases C-OCE showed better diagnostic parameters independently of the tumor type. These findings confirm the high potential of OCT-based examinations for rapid and accurate diagnostics during breast conservation surgery.

Multimodal Optical Coherence Tomography for Intraoperative Evaluation of Tumor Margins and Surgical Margins in Breast-Conserving Surgery

“…However, the breast tumor margin with the neighboring fibrous stroma is better visualized giving higher contrast on OCE images. This study, as well as the earlier studies of the authors [ 22 , 23 ], demonstrates the OCE ability to detect various degenerative changes in the connective tissue of BC stroma (fibrosis, hyalinosis, etc.) to identify lymphohistiocytic inflammation and to distinguish adipose and connective tissues from tumor cell clusters.…”

“…The range of stiffness values for elastographic maps was chosen so that the colors best represent different types of tissue (tumor and non-tumor). The authors’ earlier publications [ 22 , 23 ] define typical ranges of the elastic modulus (Young’s modulus) of five major morphological components of breast tissue by targeted comparison of histological and OCE images. The stiffest areas (blue-green color — over 400 kPa) indicate the presence of tumor cell clusters (scale of at least 300 μm), whereas the softest areas (red color — below 100 kPa) show adipose and unaltered connective tissue.…”

Optical Diagnostics in Human Diseases

“…Gubarkova and colleagues compared two types of optical coherence tomography-cross-polarization OCT (CP OCT) and a novel type of compressional optical coherence elastography. They confirmed the high potential of OCT-based examinations for rapid and accurate diagnostics during breast conservation surgery [2]. Iida and colleagues conducted Monte Carlo simulation of shortwave-infrared (SWIR) fluorescence photon migration in voxelized media for breast cancer detection.…”

Compression Optical Coherence Elastography for Assessing Elasticity of the Vaginal Wall under Prolapse after Neodymium Laser Treatment

“…Over the past decade, one of new the modalities of the multimodal OCT, called OCE, became a high-contrast technique (with the resolution of ~tens of micrometers), which outperforms the conventional structural OCT in terms of specificity and sensitivity to some important pathological processes [44]. OCE enables visualization of absolute values of stiffness (elastic Young's or shear modulus) of mapping biological tissues [45][46][47][48].…”