Department of Pathology, The China-Japan Friendship Hospital, Beijing, China.
Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA.
Cancer Med. 2022 Jan;11(1):40-49. doi: 10.1002/cam4.4419. Epub 2021 Dec 1.
The BRAF mutation is valuable for the diagnosis, prognosis, and therapy of papillary thyroid cancer (PTC). However, studies related to this mutation have involved only a small number of patients. Therefore, we performed a large-scale analysis from a single institute to evaluate the accuracy of combined fine-needle aspiration (FNA) and BRAF mutation tests for PTC diagnosis.
A total of 4600 patients with thyroid nodules who underwent both FNA cytology and BRAF mutation analysis on FNA specimens were enrolled. The association between the BRAF mutation and clinicopathological features was analyzed. A separate analysis was performed for the 311 patients who underwent repeated FNA for comparison of cytological evaluation and BRAF mutation results. The diagnostic efficacy of the BRAF mutation test and cytologic diagnoses was evaluated for 516 patients who underwent preoperative FNA tests in comparison with conclusive postoperative histopathologic results.
The cytology results of all 4600 FNA samples were categorized according to The Bethesda System for Reporting Thyroid Cytology (TBSRTC) stages I-VI, which accounted for 11.76%, 60.02%, 6.46%, 3.61%, 6.71%, and 11.43% of the samples, respectively. The BRAF mutation was detected in 762 (16.57%) FNA samples, with rates of 1.48%, 0.87%, 20.20%, 3.01%, 66.02%, and 87.81% for TBSRTC I-VI lesions, respectively. Among the 311 repeat FNA cases, 81.0% of the BRAF -positive and 4.3% of the BRAF -negative specimens with an initial indication of cytological non-malignancy were ultimately diagnosed as malignant by repeat FNA (p < 0.001). Among the 516 patients who underwent thyroidectomy, the sensitivity and specificity of the BRAF mutation test alone for PTC diagnosis were 76.71% and 100.0%, respectively, which increased to 96.62% and 88.03%, respectively, when combining the BRAF mutation test with cytology. BRAF mutation was significantly associated with lymph node metastasis (p < 0.001), but not with age, gender, or tumor size.
The BRAF mutation test in FNA samples has potential to reduce false negatives in PTC diagnosis, and therefore plays an important role in the diagnosis of thyroid nodules, especially those with an indeterminate or nondiagnostic cytology, which should be considered for repeat FNA.
BRAF 突变对甲状腺乳头状癌（PTC）的诊断、预后和治疗具有重要价值。然而，与该突变相关的研究仅涉及少数患者。因此，我们进行了一项来自单一机构的大规模分析，以评估联合细针抽吸（FNA）和 BRAF 突变检测对 PTC 诊断的准确性。
共纳入 4600 例接受 FNA 细胞学和 BRAF 突变分析的甲状腺结节患者。分析 BRAF 突变与临床病理特征的关系。对 311 例因细胞学评估和 BRAF 突变结果不一致而重复接受 FNA 的患者进行单独分析。对 516 例行术前 FNA 检查的患者进行 BRAF 突变检测和细胞学诊断的诊断效能评估，并与明确的术后组织病理学结果进行比较。
所有 4600 例 FNA 样本的细胞学结果均根据甲状腺细胞病理学报告的 Bethesda 系统（TBSRTC）分期 I-VI 进行分类，分别占样本的 11.76%、60.02%、6.46%、3.61%、6.71%和 11.43%。762 例（16.57%）FNA 样本中检测到 BRAF 突变，TBSRTC I-VI 病变的 BRAF 突变率分别为 1.48%、0.87%、20.20%、3.01%、66.02%和 87.81%。在 311 例重复 FNA 病例中，81.0%的 BRAF 阳性和 4.3%的 BRAF 阴性、初始细胞学非恶性的标本最终通过重复 FNA 诊断为恶性（p<0.001）。在 516 例行甲状腺切除术的患者中，BRAF 突变检测单独用于 PTC 诊断的敏感性和特异性分别为 76.71%和 100.0%，当将 BRAF 突变检测与细胞学检查相结合时，敏感性和特异性分别提高至 96.62%和 88.03%。BRAF 突变与淋巴结转移显著相关（p<0.001），但与年龄、性别或肿瘤大小无关。
FNA 样本中的 BRAF 突变检测有可能减少 PTC 诊断中的假阴性，因此在甲状腺结节的诊断中具有重要作用，特别是对于那些细胞学结果不确定或无法诊断的病例，应考虑重复 FNA。
