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CNB Useful in Assessing Salivary Gland Lesions

by Amy Eckner •

How sensitive and accurate is core needle biopsy (CNB) for salivary gland lesion assessment?

Background: Accurate pre-operative benign/malignant salivary gland tumor categorization is crucial in planning a correct surgical resection. Historically, fine needle aspiration (FNA) has been used with multiple imaging modalities, but in certain circumstances FNA has limitations. Recent studies show a role for CNB in pre-operative evaluation, but CNB also has some disadvantages. Its exact evaluation role has yet to be defined.

Study design: Database review of studies from PubMed, Embase, CAB Abstracts, CINAHL, BIOSIS, LILACS, PakMediNet, Trip Database, and the National Guideline Clearinghouse.

Setting: Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City.

Synopsis: Five studies that included 512 procedures were used for analysis. Study authors used strict methods for study inclusion to keep the degree of heterogeneity among studies at insignificant levels and bias risks low for patient selection, index test, and reference standard. The study quality was generally high, and all had complete follow-up (histology or clinical observation). The summary estimates for sensitivity and specificity were 0.96 and 1.00, respectively. Eight hematomas and one case of temporary facial weakness secondary to anesthesia were reported, but there were no cases of permanent facial nerve injury or tumor seeding. The CNB nondiagnostic rate was only 1.6%, compared with the previously reported 8% FNA cytology inadequacy rate. There is a potential for review bias, however, because excisional histology is generally reviewed with a prior knowledge of the CNB results.

Bottom line: CNB has high sensitivity and specificity and a low risk of complications and is a reasonably safe and diagnostically accurate method for salivary gland lesion pre-operative assessment.

Citation: Witt BL, Schmidt RL. Ultrasound-guided core needle biopsy of salivary gland lesions: a systematic review and meta-analysis. Laryngoscope. 2014;124:695-700.