The diagnostic accuracy of ultrasonography versus endoscopy for primary nasopharyngeal carcinoma

Abstract

Objective: To compare the accuracy of ultrasonography (US) with the current clinical standard of endoscopy for a diagnosis of nasopharyngeal carcinoma (NPC).

Methods: A total of 150 patients suspected of having NPC underwent US and endoscopy. A diagnosis was obtained from an endoscopic biopsy collected from each suspected tumor and was compared with a biopsy obtained from a normal nasopharynx. The diagnostic accuracy of US and endoscopy for NPC was evaluated using receiver operating curve (ROC) analysis performed by MedCalc Software.

Results: The sensitivity, specificity, and accuracy of US versus endoscopy for this cohort were 90.1%, 84.8%, and 87.3% for US, and 88.7%, 97.5%, and 93.3% for endoscopy, respectively. Both US and endoscopy exhibited good diagnostic accuracy for NPC with area under the curve (AUC) values of 0.929 and 0.938, respectively. However, this difference was not significant (Z = 0.36, P = 0.72).

Conclusion: US is a useful tool for the detection of tumors in endoscopically suspicious nasopharynx tissues, and also for the detection of subclinical tumors in endoscopically normal nasopharynx tissues.

Figure 1. Diagnostic accuracy of US and endoscopy using ROC analysis for this cohort (n = 150).

Figure 2. A 60-year-old male with NPC underwent US and endoscopy.

A large focal mass was detected on the right side of the nasopharynx by both US and endoscopy. A: An US image obtained by applying a 3.5–5.0 MHz convex-array transducer to the oblique plane. The large focal mass present in the nasopharynx is indicated with an arrow (grade 3). B: An US image of the transverse plane also showed a mass present (indicated with arrow). C: An US image scanned from the left detected normal nasopharynx tissue. The parotid gland (PG) provided an acoustic window with air from the upper pharyngeal recess (indicated with arrowhead) descending to the nasopharynx (indicated with curved arrow). D: An endoscopy image of a focal mass (indicated with arrow) present in the nasopharynx.

Figure 3. A 35-year-old female with NPC that was confined to the mucosa of the left pharyngeal recess underwent US and endoscopy.

A: An oblique US image obtained using a 3.5–5.0 MHz convex-array transducer showed that the tumor caused a focal mass (indicated with arrow) in the pharyngeal recess (US grade 3). B: An endoscopy image also showed a focal mass (indicated with arrow) present in the pharyngeal recess.

Figure 4. A 45-year-old female with NPC underwent US and endoscopy.

A: An oblique US image obtained using a 3.5–5.0 MHz convex-array transducer is shown. The tumor had infiltrated (indicated with arrow) the nasopharynx (US grade 3). B: An endoscopy image showed the pharyngeal recess to be slightly rough (indicated with arrow). C: A non-keratinizing undifferentiated carcinoma confirmed by pathology.

Figure 5. An US image obtained using a 3.5–5.0 MHz convex-array transducer applied to the oblique plane of a 75-year-old female with NPC that was not detected by endoscopy.

A NPC (grade 4) with a submucosal component (indicated with arrow) that had deeply invaded the parapharyngeal space (indicated with curved arrow) was detected.