BRAF V600E detection in cytological thyroid samples: A key component of the decision tree for surgical treatment of papillary thyroid carcinoma

Hemithyroidectomy in Papillary Thyroid Cancers: A Prospective, Single Institutional Surgical Audit and Contemplating on the Clinical Implications of 2015 American Thyroid Association Guidelines

Papillary thyroid carcinoma (PTC) contributes to 88% of thyroid malignancies and its extent of surgical management has been a topic of debate in the past 2 decades. American thyroid association (ATA) recommendations have been periodically updated for its robust and evidence-based management. We present our experience in implementing 2015 ATA guidelines, assessment of surgical outcomes of hemithyroidectomy in PTC ≤ 4 cm and contemplating on the potential clinical implications of 2015 ATA guidelines. A prospective study in a cohort of Bethesda class V and VI PTC with nodule ≤ 4 cm who underwent Hemithyroidectomy between 2012 and 2020. Data on thyroid nodule evaluation, management, histopathology and follow up were used for risk stratification. Of 37 patients, 27 (72.9%) were low risk and 10 (37%) were intermediate risk ATA group. 4 (40%) intermediate risk patients had structural incomplete response and underwent completion thyroidectomy. 1 (2.7%) out of 4 completion surgery patients required adjuvant radio-ablation iodine (RAI) and 3 patients were under surveillance. Overall, 2 (5.4%) of 37 patients, 1 each from low and intermediate groups were given remnant RAI in view of aggressive histology, old age and unwillingness for a completion surgery. During follow up of 4.94 ± 2.4 years, 35 (94.5%) showed excellent response and 2 (5.4%) showed biochemical incomplete response. The difference in RFS between two groups was statistically significant with p < 0.001. Thyroid preserving surgery combined with real time risk stratification seems appropriate for low and intermediate risk PTC ≤ 4 cm.

BRAF V600E mutation and the Bethesda System for Reporting Thyroid Cytopathology of fine-needle aspiration biopsy for distinguishing benign from malignant thyroid nodules

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) predicts the risk of malignancy for the different categories of the ultrasound-guided fine-needle aspiration biopsy (FNAB). The objective of this study is to investigate the efficiencies of the v-raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E mutation test and the TBSRTC categories in distinguishing between benign and malignant thyroid nodules.

METHODS

In this study, 362 ultrasound-guided fine-needle aspiration (FNA) samples from 344 patients aged from 17 to 76 years old were retrospectively reviewed. The patients were classified into six groups (I-VI) according to the TBSRTC system. The amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) was used to evaluate the BRAF V600E mutation level in total 362 samples. Among of the 344 patients, 128 patients (131 thyroid nodules) who underwent surgeries were followed by histopathological examination. The predictive values of the BRAF V600E mutation test and TBSRTC categories were evaluated in these 131 thyroid nodules.

RESULTS

The median ages of the patients in the TBSRTC IV-VI group were smaller than those in the TBSRTC I-III groups. The proportion of nodules over 1 cm was larger than it in the TBSRTC IV group compared to the other groups. Significant differences in BRAF V600E mutation were observed (P < .001) among these six groups. The sensitivity (89.57%) for the detection of malignant thyroid nodules, negative predictive value (NPV; 45.45%) for the detection of benign nodules, and accuracy (86.26%) for distinguishing between benign and malignant thyroid nodules increased by combining the BRAF V600E mutation test and TBSRTC system when compared with the BRAF V600E mutation test and TBSRTC system respectively. The BRAF V600E mutation test alone demonstrated the increased positive predictive value (PPV; 98.91%) and specificity (93.75%) for the detection of malignant thyroid nodules compared to the TBSRTC method (alone or in combination with the BRAF V600E method).

CONCLUSION

In summary, significant differences in age, nodule diameter, and BRAF V600E mutation were noted among the six categories of the TBSRTC system. The combination of the BRAF V600E mutation test and TBSRTC system demonstrated increases in the NPV, sensitivity, and accuracy, while the BRAF V600E method proved superiority to the TBSRTC system with regard to the PPV and specificity.

Testing for BRAF (V600E) Mutation in Thyroid Nodules with Fine-Needle Aspiration (FNA) Read as Suspicious for Malignancy (Bethesda V, Thy4, TIR4): a Systematic Review and Meta-analysis

In patients with thyroid fine-needle aspiration (FNA) report of suspicious for malignancy (SFM), both lobectomy and thyroidectomy might be considered. BRAF mutation analysis could guide towards accurate surgical therapy. The primary outcome was the reliability of BRAF (V600E) in detecting malignancy in nodules with FNA reading of SFM. The secondary outcome was to analyze its positive predictive value (PPV) and negative predictive value (NPV) considering the surgical histology as gold standard. A literature search of online databases was performed in June 2019. BRAF prevalence among thyroid nodules with FNA read as SFM according to the most popular classification systems (i.e., Bethesda V, Thy4, TIR4 category) was searched. The random-effects model was used. Three hundred sixty original articles were identified and 34 were finally included in the study. There were 1428 thyroid nodules with FNA read as SFM and 1287 (90.1%) lesions underwent surgery with a cancer rate 89.6%. The pooled prevalence of BRAF (V600E) mutation among all nodules with SFM cytology was 47% (95% CI = 40 to 54, I2 = 85.5%). Pooled PPV and NPV of BRAF testing were 99% (95% CI, 97-99) and 24% (95% CI, 16-32), respectively. BRAF (V600E) mutation was found in about one in two nodules with thyroid FNA read as SFM, its PPV to detect cancers was excellent, and its NPV was very poor. The routine BRAF testing in FNA read as SFM cannot be recommended. BRAF (V600E) test may be useful to extend surgical approach in selected cases with further suspicious clinical/ultrasound features.

The synergic effect of BRAFV600E mutation and multifocality on central lymph node metastasis in unilateral papillary thyroid carcinoma

The purpose of this study is to evaluate the potential synergic effect of BRAF^V600E mutation and multifocality on central lymph nodes metastasis (CLNM) in the patients with unilateral papillary thyroid carcinoma (PTC). We enrolled 413 patients with unilateral PTCs who accepted prophylactic unilateral or bilateral central lymph node dissection (LND). Univariate and multivariate analyses were made to determine the association between related factors and CLNM. Then, all patients were divided into 4 groups based on their status of BRAF^V600E mutation and multifocality. Relative excess risk of interaction (RERI), attributable proportion (AP) of interaction and synergy index (SI) were applied to evaluate the interactive effect of these two factors on CLNM. Results showed that BRAF^V600E mutation and multifocality were independent risk factors for CLNM. A further study revealed that unilateral PTCs accompanying multifocality with BRAF^V600E mutation had the highest incidence of CLNM compared with other subgroups. Besides, RERI was 4.323 (95% CI = 1.276-7.369), AP was 0.523 (95% CI = 0.364-0.682) and SI was 2.469 (95% CI = 1.607 to 3.794), indicating a significant additive interaction of BRAF^V600E mutation and multifocality on CLNM. The present study has confirmed that BRAF^V600E mutation and multifocality are risk factors for CLNM in unilateral PTC. Additionally, unilateral PTC patients accompanying multifocality with BRAF^V600E mutation may have an increased risk of CLNM in clinically negative CLNM.