Investigation and Observation of the Pharynx to the Cervical Esophagus Using Trans-nasal Endoscopy with Image-enhanced Endoscopy for Early Detection of Head and Neck Cancers

Introduction: We started endoscopic treatment for superficial pharyngeal cancer in 1996, and thus
far, 97 lesionsof 77 cases of superficial head and neck cancer have been detected using trans-oral
endoscopy. However, some areas are difficult to observe with trans-oral endoscopy because of the
gag reflex. We have therefore applied trans-nasal endoscopy for observing of the pharynx to the
cervical esophagus.
Methods: To avoid overlooking cancers located at the floor of the mouth, soft palate and uvula, we
first observethe oral cavity. After administering local anesthesia to the nose without sedation, the
endoscope is inserted through the nose. When the tip of the endoscope reaches caudal to the uvula,
the patient opens his or her mouth wide, sticks the tongue forward as far as possible and makes a
makes a vocalization like “ayyy”. The endoscopist then makes the endoscope take a U-turn and
observes the oropharynx, particularly radix linguae. To examine the hypopharynx and the orifice of the
esophagus, the patient is asked to blow hard and puff their cheeks while the mouth remains closed.
This approach provides a much better view of the orifice of the esophagus than is possible with transoral
endoscopy with deep sedation.
Results: In this study, we detected 31 superficial cancers of the oral cavity. Previous efforts to detect
suchcancers using trans-oral endoscopy have failed. In addition, we were never able to detect early
cancers located at base of tongue in the past, but since implementing the intra-oropharyngeal U-turn
method, we have detected 27lesions. We were also never able to detect early cancers located at the
pharyngoesophageal junction in the past, but since implementing the modified Valsalva maneuver, we
have detected more than 30 cases. Between 2008 and 2019 a total of 346 lesions of 221 cases of
superficial head and neck cancer were detected by trans-nasal endoscopy, which were more than 3
timesthe lesions detected by previous screening. Mucosal redness, white deposits or loss of a normal
vascular pattern and proliferation of vascular pattern such as small dots or salmon roe with a close-up
view of it are important characteristics to diagnose superficial pharyngeal cancer. Moreover, a
brownish area using image-enhanced endoscopy is useful for early diagnosis. With adequate
extension of the pharyngeal mucosa using the Valsalva maneuver, observing the protruded areas
should prove useful for diagnosing the depth of invasion.