Project Summary/Abstract Our overarching goal is to aid anal cancer screening using a new, non-invasive imaging approach termed probe-based light sheet microscopy (pLSM). Incidence and mortality of anal cancer have been rapidly increasing: mortality increased by 5.7% per year between 2014 and 2020. The recent ANCHOR (Anal Cancer HSIL Outcomes Research) trial published in late 2022 showed that treatment of anal precancer (high-grade squamous intraepithelial lesion, HSIL) significantly reduces the risk of anal cancer. Therefore, it is expected that anal cancer screening in high-risk populations will become standard of care. However, high-resolution anoscopy, an integral component of anal cancer screening and treatment, has low-to-moderate diagnostic performance, and trained anoscopists are scarce due to a steep learning curve and no standardized training opportunities. In a recent Trailblazer R21 project, we developed a new optical microscopy approach termed scattering-based light sheet microscope (sLSM). While LSM is not new and has been widely used for imaging fluorescence- labelled samples in biology research, we optimized LSM for imaging animal and human tissues using the intrinsic scattering contrast for clinical applications. In our preliminary study, we imaged fresh anal biopsies (n = 110) ex vivo with a bench sLSM device and found that i) sLSM could clearly visualize the critical morphologic features pathologists use to diagnose anal squamous intraepithelial lesions and ii) could provide high diagnostic accuracy (overall accuracy = 87%; HSIL accuracy = 91%). In this 4-year R01 project, we will develop a new, probe-based light sheet microscopy (pLSM) device and evaluate its clinical utility for imaging human subjects in vivo. During anal cancer screening, the anoscopist directly places the pLSM device on the anal mucosa and examines the cellular details of the tissue. The pLSM images are analyzed by a trained clinician (pathologist or anoscopist) or by automated image analysis algorithms. The pLSM image findings guide the clinician to areas concerning for HSIL, which can increase the screening sensitivity and reduce the morbidity caused by unnecessary biopsy of benign and low-grade squamous intraepithelial lesions (LSILs). Additional unique benefits of pLSM are: i) providing a novel feedback tool during high-resolution anoscopy training, ii) non-invasive monitoring of suspicious lesions over time, and iii) enabling same-day treatment for patients at a greater risk of being lost to follow up. The specific aims of this project are to Develop a pLSM device (Aim 1), Evaluate the clinical utility of pLSM in an in vivo human imaging study (Aim 2), and Develop automated image analysis algorithms (Aim 3). We are a multi-institute, interdisciplinary research team who has been collaborating successfully for over 4 years. We bring together expertise in optical engineering (University of Arizona, Memorial Sloan Kettering), anal cancer and pathology (Stanford), and image data analysis (UA, MSK).

Project Narrative We aim to significantly improve anal cancer screening, using a novel imaging tool termed probe-based light sheet microscope (pLSM). The pLSM device non-invasively examines cellular details of anal tissues, which can be used to provide high accuracy for diagnosing anal lesions. The pLSM image findings can guide the clinician to areas concerning for precancer, which can increase the screening sensitivity and reduce the morbidity caused by unnecessary biopsy of benign and low-grade squamous intraepithelial lesions.