OR28-05 Approaching Indeterminate Thyroid Nodules in the Absence of Molecular Markers. “The BETH-TR Score”

Abstract

Context: Given the lack of easy access to molecular markers, for indeterminate thyroid nodules (Bethesda (BETH) category III, IV), the clinician can either decide to get a second opinion from an expert high volume thyroid cytopatholgist, re-do the FNAC after a period of 3-6 months or send the patient for a diagnostic hemithyroidectomy. Reviewing the sonographic risk features is also one way of triaging these nodules. The ACR-TIRADS (TR) is an objective method of sonographic risk assessment and is superior to other forms of sonographic classification. Aim: We propose combining the scoring of TR category and BETH category (both expressed as numerical value and summated) and look at the score which could potentially guide the clinician in deciding whom to send for surgery. Settings and Design: Observational Prospective collection of consecutive patient data from Thyroid FNAC clinic. Statistical analysis used: The BETH categories were represented numerically and summated with the TR category. The categorical outcome variables of Benign and Malignant nodules and the summated score was analysed using Kruskal-Wallis test. Results: We analysed 450 FNAC data, out of which 403 were thyroid nodule aspirates. Out of these nodules, 96 of them underwent surgery and 64% of these nodules were malignant on final histopathology (Malignant=62 and Benign=34). The mean (sd) size of the benign nodules was 3.6 (2.2)cm compared to 2.8 (1.8)cm of the malignant nodules. After excluding those with BETH 1 (n=4), the mean BETH-TR score for benign nodules was 6(1.4) and malignant nodules 9.4(2.1) (p<0.0001). The BETH-TR score progressively increased from 7.3(0.92) in Follicular thyroid cancers (FTC) to 8.6(1.4) in Follicular variant Papillary thyroid cancer (FVPTC) to 10(1.3) in classic Papillary thyroid cancers (PTC). Among the indeterminate nodules (BETH III & IV; n=40), the BETH-TR score of benign nodules was 6.75(1) and malignant nodules was 7.5(0.72) (p value=0.01). A BETH-TR score >=7 gave a sensitivity of 92% specificity of 74% and correctly identified malignant nodules in 86% of cases (Likelihood ratio 3.5; ROC area: 0.8841; CI 0.79-0.94). Conclusion: A combined sono-cytological BETH-TR score is one way to triage management of indeterminate thyroid nodules. A BETH-TR score >=7 gave a sensitivity of 92% specificity of 74% and correctly identified malignant nodules in 86% of cases.