NBI to Detect Post-RT Mucosal Residual NPC

Using Narrow-band Imaging (NBI) Technique to Detect Post-radiotherapy Mucosal Residual Nasopharyngeal Carcinoma (NPC)

NBI has been proven to be a useful tool to detect early NPC, but they were few studies concerning the detection of post-radiotherapy mucosal residual NPC using NBI system

Background NPC has a uniquely high prevalence in Southern China. According to the Hong Kong Cancer Registry in 2012, NPC was the sixth commonest cancer in men and thirteenth in women. It accounted for 2.9% of all new cancer cases. In 2012, there were 819 new cases of NPC. NPC is highly radiosensitive. Radiotherapy and chemotherapy are the mainstay of treatment. Despite the chemo-irradiation, disease control failure still occurred in NPC patients presenting as persistent tumor. Early detection of those post-radiotherapy residual NPC is essential for early arrangement of salvage therapy. Detection methods include imaging, plasma Epstein-Barr virus DNA, endoscopy examinations and nasopharynx biopsy. NBI system has been well proven as a tool to detect early digestive tract cancer and head and neck cancer. However, there were only few studies targeting the detection of post-radiotherapy mucosal residual of NPC using NBI system Objective To identify the vessel pattern of those confirmed NPC case using NBI system To identify the endoscopy features of post-radiotherapy mucosal residual nasopharyngeal carcinoma using NBI system To establish the positive predicted value, negative predicted value, sensitivity and specificity of using NBI system for detecting mucosal residual NPC Method: All newly biopsy confirmed NPC patient will be assessed, their nasopharynx endoscopic image will be captured using both WL + NBI system At post-radiotherapy 8th weeks, endoscopic examination will be arranged for patient using both WL + NBI system, biopsy will also be taken to detect mucosal residual NPC

All post-radiotherapy 8 weeks NPC patient will routinely undergo laryngoscope examination (WL system) and NP biopsy will be taken at the same time to determine if there is any residual NPC. In this study, laryngoscope with NBI system will be used. NBI system will be turn on during the post radiotherapy 8 week laryngoscope examination in additional to routine WL system

All post-radiotherapy 8 weeks NPC patient will routinely undergo laryngoscope examination (WL system) and NP biopsy will be taken at the same time to determine if there is any residual NPC. In this study, laryngoscope with NBI system will be used. NBI system will be turn on during the post radiotherapy 8 week laryngoscope examination in additional to routine WL system

Positive Nasopharynx Biopsy Results Detected by NBI System in Those Post-radiotherapy 8th Week NPC Patient

4 grading of NBI vessel patterns can be identified in those post-radiotherapy 8 weeks NPC patients. Grade A: normal vessel size and length, regular pattern Grade B: normal vessel size, short, regular spiderweb like pattern Grade C: irregular vessel size and length, distorted and irregular pattern Grade D: thickened vessel size, elongated, distorted, and earthworm pattern

Non suspicious pattern = grade A + grade B Suspicious pattern = grade C + D The sensitivity, specificity, positive predicted valve and negative predicted valve of detecting mucosal residual NPC using NBI suspicious/ non suspicous pattern can be thus calculated.

The Sensitivity, Specificity, Positive Predicted Valve and Negative Predicted Valve of Detecting Mucosal Residual NPC Using NBI Suspicious/ Non Suspicous Pattern

Non suspicious pattern = grade A + grade B Suspicious pattern = grade C + D The sensitivity, specificity, positive predicted valve and negative predicted valve of detecting mucosal residual NPC using NBI suspicious/ non suspicous pattern can be thus calculated.

Inclusion Criteria: all new NPC patient Exclusion Criteria: History of radiotherapy to head and neck region Poor premorbid status/ non-communicable patients <18 years old Pregnancy