INTRODUCTION: Current guidelines recommend that in patients presenting with clinically palpable nodules or with an ultrasound finding of a thyroid nodule, one has to evaluate its risk for malignancy by proceeding with a fine needle aspiration biopsy (FNAB). The decision to do FNAB would depend on ultrasonographic features of the nodule, which include its size, hypoechogenicity, presence of microcalcifications, increased central vascularity, infiltrative margins, and taller than wide measures on transverse plane. Elastography, a measure of tissue stiffness, is now also being utilized as another feature that has a positive correlation with malignancy. This study hopes to determine which among the abovementioned ultrasonographic features would best correlate with a higher risk for thyroid malignancy among adult patients who had undergone ultrasound guided FNAB.
METHODOLOGY: A prospective study was done in a cohort of all Filipino patients 19 years old and above who underwent ultrasound guided FNAB of the thyroid nodule/s from July to December 2013 at the Radiology Section of The Medical City, Pasig City, Philippines. Specimen obtained from FNAB were then reviewed by a pathologist to determine its cytopathology and categorized based on the Bethesda System of Classification. The cytopathology reports were correlated with the features seen on the patient's thyroid ultrasound to determine which characteristic would be predictive of malignancy.
RESULTS: A total of 100 patients underwent ultrasoundguided FNAB, from which 157 nodules were biopsied. 27 nodules were excluded from the analysis due to non-diagnostic or unsatisfactory (Bethesda Category I) findings on cytopathology. Among the 100 patients, 86% of which were females with the mean age of 41 ± 11.31 in those found to have malignant cytopathologic diagnosis. Of the 130 nodules biopsied, 115 nodules were identified as benign (Bethesda Category II) while 15 were identified to be malignant or suspicious for malignancy (Bethesda Category III-VI). Each of the five sonographic features that were predictive of malignancy was compared between the two outcome groups (benignversus malignant). Among them, only the presence of microcalcifications on ultrasound showed to be significantly correlated with malignancy with an odds ratio of 11.3. Ultrasound evaluation with elastography was only performed on 24 nodules and hence results were inconclusive. A nodule possessing more than two of the ultrasound features that were predictive of malignancy was more likely to be malignant on cytopathology (p value of 0.00).
CONCLUSION: The presence of microcalcifications on thyroid nodules as seen on ultrasound is a significant predictor of malignancy and remains to be consistent locally as with foreign studies. Nodules that were proven to be malignant on cytopathology presented with more of the ultrasound features that are said to be predictive of malignancy.

Human ; Male ; Female ; Middle Aged ; Adult ; Thyroid Nodule ; Biopsy, Fine-needle ; Elasticity Imaging Techniques ; Thyroid Neoplasms ; Ultrasonography ; High-energy Shock Waves ; Calcinosis

Introduction: Low-risk papillary thyroid microcarcinomas (PTMC) have an indolent course and favorable prognosis. In the Philippines, radioactive iodine (RAI) remnant ablation is frequently given to patients with low-risk PTMC because of studies showing that Filipinos have more aggressive thyroid cancers. This study aims to determine if RAI remnant ablation prevents thyroid cancer recurrence among Filipino patients with low-risk PTMC who underwent thyroidectomy at a tertiary hospital in the Philippines. Methods: A retrospective cohort study was conducted among adult patients with low-risk PTMC who underwent total thyroidectomy from 2006 to 2016. Outcomes were classified as positive or negative for disease recurrence based on imaging results and serum thyroglobulin levels during each follow-up visit. Recurrence-free curves were estimated using Kaplan-Meier method and compared using Cox regression analysis. Results: A total of 90 cases of low-risk PTMC were included in the analysis with a mean follow-up duration of 41.88 months (range, 12-129 months). Forty eight patients (53.33%) underwent RAI remnant ablation (RAI group) and 42 patients (46.67%) did not (No RAI group). Six patients (6.67%) had disease recurrence at a median of 18 months (range, 12-70 months). The recurrence rates in the No RAI group were 2.8% at one year and 10.84% in five years and the recurrence rates in the RAI group were 0% at one year and 9.84% at five years. (HR, 5.34; 95% CI, 0.86 to 33.02; P=0.07). Conclusion This study did not provide sufficient evidence that RAI remnant ablation prevents disease recurrence in Filipino patients with low-risk PTMC. Future randomized, prospective trials involving larger sample sizes and longer follow-up duration are necessary to confirm our findings.
Thyroid Neoplasms

Objective: To compare the diagnostic performance of American College of Radiology-Thyroid Image Reporting and Data Systems (ACR-TIRADS) and the American Thyroid Association (ATA) guidelines on screening for thyroid malignancy. Methodology: A cross-sectional criterion-referenced study involving Filipino patients with thyroid nodules, 18-80 years old, who underwent ultrasound guided fine needle aspiration biopsy at the Thyroid Clinic of The Medical City from July to December 2019. The ACR-TIRADS and the ATA guidelines were compared for 197 nodules. Standard diagnostic parameters were calculated, namely sensitivity, specificity, PPV, NPV, positive and negative likelihood ratios and overall accuracies. Results: The risks of malignancy were 15% and 22% for TIRADS 4 and 5 respectively. For ATA guidelines, it’s 2%, 20%, and 15% for nodules with low, intermediate, and high suspicion respectively. The sensitivity, specificity, PPV, NPV, and accuracy of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TIRADS) in relation to Fine Needle Aspiration Cytology (FNAC) is 100%, 52.2%, 16.5%, 100%, and 56.4% respectively. For the American Thyroid Association (ATA) guidelines it is 88.2%, 57.8%, 16.5%, 98.1%, and 60.4% respectively. Conclusion The ACR TIRADS classifications appears to be more sensitive than the ATA classification. The ATA guidelines prove to be a more specific test. Each tool has its unique advantages and disadvantages. Therefore, clinicians must use these tools with utmost vigilance to avoid over or under diagnosis and to avoid unnecessary thyroid nodule biopsies.
Thyroid Neoplasms ; Thyroid Nodule