Quantitative and longitudinal monitoring of cancer cell invasion in a three-dimensional in vitro model of oral cancer using optical coherence tomography

We previously developed a three-dimensional (3D) organotypic culture model of oral squamous cell carcinoma (OSCC) by incorporating cancer-associated fibroblasts to replicate oral tissue architecture and the tumor microenvironment (TME). This model provides a relevant platform for investigating cancer cell invasion. Optical coherence tomography (OCT), a noninvasive, high-resolution imaging technique, enables both real-time and longitudinal observations. This study assessed the applicability and feasibility of combining OCT with deep learning for the quantitative, longitudinal monitoring of cancer cell invasion in our 3D model. OCT effectively captured cross-sectional images and identified three regions-original cancer cell region, invasive cancer cell region, and stromal layer-based on scattering intensity and optical density, demonstrating nondestructive visualization of tissue microarchitecture. Sequential OCT imaging facilitated 3D image reconstruction and repeated monitoring. Planimetric and volumetric analyses of 3D OCT images revealed internal structural alterations and enabled comparative evaluation of invasion behaviors across OSCC cell types, TME conditions, and culture durations. Moreover, the invasiveness parameter obtained from 3D OCT images strongly correlated with histomorphometric-based data, confirming its reliability. These findings support the use of OCT imaging as a promising tool for noninvasive, quantitative assessment of invasiveness in organotypic cancer models.