Current status of core needle biopsy of the thyroid

PERSPECTIVE This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Thyroid nodules are a common clinical problem. Fine-needle aspiration (FNA) and large-needle biopsy have been used to diagnose thyroid nodules [1,2]. Before the 1980s, large-needle biopsy was the standard procedure for the thyroid, but FNA became the standard diagnostic tool in the 1980s because it is a safe procedure that leads to accurate diagnoses [3]. With advances in core needle biopsy (CNB) devices (i.e., spring-activated core needles) and development of high-resolution ultrasound, it has become possible to make accurate diagnoses while minimizing complications [4]. Although 18-to 21-gauge core needles can be used to biopsy thyroid nodules, 18-gauge needles are most commonly used in Korea [5,6]. The relationships among the size of the needle, the number of core specimens, and diagnostic accuracy have not yet been conclusively established, but the general tendency is that thinner needles cause less damage to the normal thyroid, but allow a smaller amount of thyroid tissue to be biopsied to be obtained. These relationships may be validated in the future. (KSThR) have proposed CNB for thyroid nodules with previous nondiagnostic FNA results [7-9]. The AACE/ACE/AME, British Thyroid Association, and KSThR have suggested CNB for lymphoma, anaplastic carcinoma, medullary carcinoma, and metastasis to the thyroid [8-10]. However, the American Thyroid Association does not recommend the use of CNB [11]. Recently, CNB has been used for various kinds of thyroid nodules. CNB has been suggested as an alternative to FNA in patients with previous nondiagnostic results [12] or atypia of undetermined significance [13]. It is also useful for the differentiation of rapidly growing thyroid tumors (lymphoma vs. anaplastic thyroid carcinoma), the differentiation of follicular lesions (follicular neoplasm vs. nodular hyperplasia), medullary thyroid carcinoma, calcified thyroid nodules, and degenerating thyroid nodules [6,14,15]. Several studies have suggested the value of CNB as a first-line diagnostic tool for the thyroid [16]. According to a meta-analysis [17], both CNB and FNA had a specificity of 99.5%, but the sensitivity was higher for CNB (74% [95% confidence interval, 67% to 81%] vs. 50% [95% confidence interval, 44% to 56%]). CNB also demonstrated significantly fewer nondiagnostic (5.5%, P<0.001) and inconclusive (8.0%, P<0.001) results than FNA (22.6% and 40.2%, respectively). In large cohort studies including more than …