BRAF V600E Gene Testing Combined with Serum TSH, TGAb, and TPOAb Testing for the Diagnosis of Malignancy in TI-RADS 4 Nodules

Background To evaluate the diagnostic value of BRAF V600E gene testing combined with serum thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) testing for malignancy in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules. Methods This was a retrospective study of patients who were diagnosed with TI-RADS 4 nodules via ultrasound examination during an outpatient or inpatient visit, who underwent BRAF V600E gene testing, and who had histopathological results from June 2020 to June 2022 at Taizhou Cancer Hospital. We compared the baseline characteristics, namely, age, sex, presence of lymph node metastasis, tumour size, cytological results, and BRAF V600E gene testing results, of the two patient groups according to their postoperative pathological results. Using postoperative pathology as the gold standard, the sensitivity and specificity of serum TSH, TGAb, and TPOAb and BRAF V600E gene testing alone for diagnosing malignant TI-RADS 4 nodules and the area under the curve (AUC) were calculated. The four indicators were then combined to diagnose TI-RADS 4 nodule malignancy, and the sensitivity, specificity, and AUC were calculated. Results Among 112 patients with TI-RADS 4 nodules, 89 had malignant nodules, and 23 had benign nodules. The proportions of patients with TI-RADS 4 nodules aged ≥ 50 years and aged < 50 years were 89.9% (71/79) and 54.5% (18/33), respectively (P = 0.000). The proportion of malignant TI-RADS 4 nodules > 1 cm was significantly greater (86.8% [33/38]) than that of nodules ≤ 1 cm (75.7% [56/74], P = 0.003). None of the benign modules were positive for the BRAF V600E gene mutation, but 73.0% of malignant nodules had this mutation (P = 0.000). Among patients with and without the BRAF V600E gene mutation, 30.8% and 12.8%, respectively, had cervical lymph node metastasis (P = 0.026). The sensitivity and specificity of BRAF V600E gene testing for diagnosing malignancy in TI-RADS 4 nodules were 100% and 48.94%, respectively. However, when the BRAF V600E gene was combined with the serum TSH, TGAb, and TPOAb levels, the specificity and AUC of the combined indicators were 100% and 0.891, respectively. Conclusion The combination of BRAF V600E gene testing and serum TSH, TPOAb, and TGAb testing has good clinical value for diagnosing malignancy in TI-RADS 4 nodules.