Surgical polarimetric endoscopy for the detection of laryngeal cancer

Nature Biomedical Engineering | Volume 7 | August 2023 | 971–985 971 nature biomedical engineering https://doi.org/10.1038/s41551-023-01018-0 Article Surgical polarimetric endoscopy for the detection of laryngeal cancer Ji Qi    1,2,3,4,5,6  , Taranjit Tatla5,7, Eranga Nissanka-Jayasuriya8, Alan Yilun Yuan9, Danail Stoyanov    2,3,4  & Daniel S. Elson    5,6  The standard-of-care for the detection of laryngeal pathologies involves distinguishing suspicious lesions from surrounding healthy tissue via contrasts in colour and texture captured by white-light endoscopy. However, the technique is insufficiently sensitive and thus leads to unsatisfactory rates of false negatives. Here we show that laryngeal lesions can be better detected in real time by taking advantage of differences in the light-polarization properties of cancer and healthy tissues. By measuring differences in polarized-light retardance and depolarization, the technique, which we named ‘surgical polarimetric endoscopy’ (SPE), generates about one-order-of-magnitude greater contrast than white-light endoscopy, and hence allows for the better discrimination of cancerous lesions, as we show with patients diagnosed with squamous cell carcinoma. Polarimetric imaging of excised and stained slices of laryngeal tissue indicated that changes in the retardance of polarized light can be largely attributed to architectural features of the tissue. We also assessed SPE to aid routine transoral laser surgery for the removal of a cancerous lesion, indicating that SPE can complement white-light endoscopy for the detection of laryngeal cancer. Laryngeal cancer is one of the most common malignancies of the upper aerodigestive tract1. Minimally invasive procedures, including endo- scopic incisional biopsy and transoral surgery, are widely used for laryngeal cancer diagnosis and intervention, respectively. Surgical endoscopy plays a key role by allowing surgeons to inspect suspicious areas in detail without having to invasively open and expose the larynx, and also to further decide where to biopsy for histopathological exami- nation or where to resect in surgical intervention. The standard-of-care is high-definition white-light endoscopy (WLE), a wide-field optical imaging technique using white-light illumination and red/green/blue (RGB) colour camera imaging of larynx tissue via a surgical endoscope, closely recreating what would be seen by the naked eye. Surgeons rely on the WLE colour and texture contrast to differentiate suspicious laryngeal lesions from surrounding normal tissue and then perform the operation. Unfortunately, tumourous lesions—especially those at the pre-cancerous and early-cancerous stages—may not always present discernible colour or texture differences, while tissue regions with abnormal colour or texture may not always be associated with cancer, leading to unsatisfactory sensitivity (as low as 51.1%) and miss rate2–5. The limitations of WLE result in inappropriate selection of biopsy tar- gets, or subtotal/unnecessary resection, negatively affecting survival rate or causing additional functional impairment for the patient. Minimally invasive procedures for laryngeal cancer can bene- fit immensely by introducing complementary surgical endoscopy Received: 6 July 2020 Accepted: 23 February 2023 Published online: 3 April 2023 Check for updates 1Research Center for Humanoid Sensing, Zhejiang Lab, Hangzhou, China. 2Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, UK. 3Department of Computer Science, University College London, London, UK. 4Centre For Medical Image Computing, University College London, London, UK. 5Hamlyn Centre for Robotic Surgery, Imperial College London, London, UK. 6Department of Surgery and Cancer, Imperial College London, London, UK. 7Northwick Park Hospital, London North West University Healthcare NHS Trust, London, UK. 8William Harvey Hospital, East Ken