Trans-oral Magnifying Endoscopy With Narrow Band Imaging for Screening of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is endemic in our region and is the 9th most common cancer in Hong Kong. Traditionally diagnosis has been through a nasoendoscopic examination of the nasopharynx with white light followed by a biopsy of suspicious lesions for a confirmatory diagnosis. However, given the geometry of the anatomy of the nasopharynx, with its inherent crevices and varying amounts of lymphoid tissues, lesions are not always easily identified leading to potential missed lesions. The non-specific aspect of white light also leads to excessive biopsies that are not without risk and of some discomfort to patients. Recent advances in liquid biopsies have also allowed for the detection of earlier and smaller lesions that are not always easily identified on nasoendoscopy but rather are seen on Magnetic Resonance Imaging (MRI).

An alternative imaging technique is the use of Narrow Band Imaging (NBI) to view the vasculature of the mucosa to identify suspicious lesions for pre-malignancy and malignancy that has been popularized in the gastrointestinal tract. In NPC, NBI with the flexible nasoendoscopes has been used in the diagnosis of NPC with varying success. Researchers at Chinese University of Hong Kong has found that in NPC NBI has limitations arising from a lack of consensus on vascular findings on NBI that constitute malignancy, lack of magnification and long focal length of current nasoendoscopes1. Flexible endoscopy using conventional esophago-gastroscopy endoscope (OGD) with NBI and magnification power up to 80x overcome the limitations of current nasoendoscopes. The passage of the endoscope through the mouth and retroflexion at oropharynx could visualize the nasopharynx clearly and detailed assessment is feasible.

Here in this study the investigators will seek to use a trans-oral magnifying endoscopy with NBI and retroflexion into the nasopharynx to view the nasopharynx to evaluate the feasibility in the diagnosis of occult nasopharyngeal carcinoma.

The aim of this study is to investigate the clinical usefulness of trans-oral magnifying endoscopy with NBI as a screening tool for patients at increased risk of nasopharyngeal carcinoma (NPC).

The investigators hypothesize that with the use of magnifying NBI trans-oral endoscopy, the nasopharynx could improve the diagnostic yield of NPC in high risk patients with negative test on conventional investigations. As a result, such endoscopic screening tool could be used routinely to identify early NPC in patients deemed at risk.