Association between thyroid nodule size and malignancy rate.

INTRODUCTION: The diagnostic performance of ultrasound-fine needle aspiration to identify thyroid nodules harbouring malignancy remains variable. The aim of this study was to determine thyroid nodule size and cytological classification as predictors of malignancy risk. MATERIALS AND METHODS: We conducted a retrospective cohort analysis at an academic hospital involving 499 consecutive patients who underwent thyroid surgery between 2004 and 2015. RESULTS: A total of 503 thyroid nodules (499 patients, 84% female; mean age 50.8 years, standard deviation, SD, 15.4 years) were analysed. Of these, 19.5% were malignant. The mean (± SD) nodule size was 3.28 ± 1.63 cm and 3.27 ± 1.54 cm for benign and malignant nodules, respectively. The odds of malignancy for thyroid nodules less than 3.0 cm was similar to those for nodules of 3.0 cm or greater (0.26 compared with 0.29; p=0.77). Overall, the sensitivity and specificity of fine-needle aspiration in this cohort were 71.4% and 100%, respectively. The overall false negative rate was 5.4%. When the cut-off of 3.0 cm was used, the false negative rate in thyroid nodules less than 3.0 cm was 0% compared with 7.0% in nodules of 3.0 cm or greater. Thus, class (p<0.01) but not nodule size (p=0.49), was associated with higher malignancy risk. CONCLUSIONS: Our results suggest that thyroid nodule size did not accurately predict the risk of thyroid malignancy irrespective of fine-needle aspiration cytology. Routine diagnostic thyroid lobectomy solely owing to thyroid nodule size of 3.0 cm or greater is currently not justified.

Inadvertent parathyroidectomy during thyroid surgery.

INTRODUCTION: Inadvertent parathyroidectomy is a recognised complication of thyroid surgery. We aimed to investigate the incidence of and risk factors for inadvertent parathyroidectomy during thyroid surgery, in our patient cohort. METHODS: A retrospective review of the records of all patients undergoing thyroid surgery in our institution between January 2012 and December 2014 was performed. Medical records, laboratory investigations and histopathology reports were evaluated. Patient demographics, indication for surgery, surgery performed, final pathology, incidental parathyroidectomy and post-operative hypocalcaemia were recorded. Univariate analysis using the Fisher's exact test was performed. RESULTS: Two hundred and thirty procedures were included: 147 hemi-thyroidectomies and 83 total thyroidectomies. Central neck dissection was also performed in 13 cases. The most common indication for surgery was indeterminate cytology (81 cases). Post-operatively, malignant disease was reported in 52 cases (22.6%). Inadvertent parathyroidectomy occurred in 40 cases (17.3%). There was a statistically significant increased risk of inadvertent parathyroidectomy with malignant disease (p = 0.001) and after central neck dissection (p = 0.013) but no difference was seen between hemi- and total thyroidectomies (p = 0.47), gender (p = 1.00) or with increasing age (p = 1.00). Hypocalcaemia occurred in four cases and was transient in three. CONCLUSION: Inadvertent parathyroidectomy is a potential risk during thyroid surgery but post-operative hypocalcaemia as a result is rare. Malignancy and more extensive surgery appear to carry an increased risk for this complication.

BRAFV600E mutation as a predictor of thyroid malignancy in indeterminate nodules: A systematic review and meta-analysis.

BACKGROUND: Thyroid nodules are usually diagnosed using fine-needle aspiration (FNA). The sensitivity limitations of FNA result in 10-30% of nodules being classified as "indeterminate". The BRAFV600E mutation is associated with papillary thyroid carcinoma (PTC). We conducted a systemic review and meta-analysis to evaluate the diagnostic utility of the BRAFV600E mutation in indeterminate nodules. METHOD: PUBMED and EMBASE were searched for studies testing for the BRAFV600E involving indeterminate nodules (Thy3a, Thy3f, Thy4) and containing information on final surgical histopathology. Thirty two studies involving 3150 indeterminate nodules were included in the analysis. RESULTS: The overall sensitivity and specificity for BRAFV600E for the diagnosis of thyroid malignancy was 0.40 (95% CI: 0.32-0.48) and 1.00 (95% CI: 0.98-1.00) respectively. The diagnostic odds ratio (DOR) was 205.4 (95% CI: 40.1-1052). With a Fagan plot, the post-test probability of thyroid cancer, given a negative mutation was 6%, but this rose to 92% with a positive result. On subgroup analysis, for Thy3a nodules, the pooled sensitivity and specificity for thyroid malignancy was 0.21 (95% CI: 0.13-0.34) and 1.00 (95% CI: 0.98-1.00). For Thy3f nodules, the pooled sensitivity and specificity was 0.09 (95% CI: 0.03-0.20) and 1.00 (95% CI: 0.05-1.00) respectively. For Thy4 nodules, the corresponding sensitivity and specificity was 0.58 (95% CI: 0.5-0.64) and 0.99 (95% CI: 0.95-1.00) respectively. CONCLUSIONS: Despite a high specificity for thyroid cancer, BRAFV600E mutation has a low overall sensitivity and therefore has a limited diagnostic value as a single screening test.