High-Suspicion Subcentimeter Thyroid Nodules: Cost Effectiveness of Active Surveillance versus Fine Needle Aspiration.

PURPOSE: To compare the cost-benefit of active surveillance (AS) against immediate fine needle aspiration (FNA) of sonographically suspicious subcentimeter thyroid nodules. MATERIALS AND METHODS: A Markov model was constructed to compare the cost-benefit of 3 strategies from the point of discovery until death: (a) Surveillance of all nodules, (b) Surveillance of nodules with positive cytology, and (c) Surgery of nodules with positive cytology. The reference case was a 40-year-old woman with a sonographically suspicious subcentimeter thyroid nodule. Transition probabilities, costs, and health state utilities were derived from the literature. Sensitivity analyses were performed to evaluate model uncertainty. Willingness-to-pay threshold was set at $100,000/quality-adjusted life year. RESULTS: Surveillance of nodules with positive cytology dominated in the reference scenario and was cost-beneficial over Surveillance of all nodules, independent of the utility of AS. Surveillance of all nodules was cost-beneficial only at a life expectancy of <2.6 years or surveillance duration of <4 years. CONCLUSIONS: While current guidelines recommend AS of sonographically suspicious subcentimeter nodules, the results of this study suggest that immediate FNA (Surveillance of nodules with positive cytology) is more cost-beneficial than AS (Surveillance of all nodules). Patients with positive cytology on FNA may subsequently opt for AS (Surveillance of nodules with positive cytology) or surgery (Surgery of nodules with positive cytology) according to their level of comfort (ie, utility) with AS.

Large thyroid nodules: should size alone matter?

BACKGROUND: The management of thyroid nodules ≥ 4 cm is controversial due to conflicting evidence on the prevalence of malignancy and diagnostic accuracy of fine-needle aspiration cytology (FNAC). Some literature recommends routine excision of large thyroid nodules due to high cytology false negative rates (FNR). We aim to investigate the diagnostic accuracy of FNAC, prevalence of malignancy in large (≥ 4 cm) thyroid nodules compared to nodules < 4 cm, and the clinical and ultrasound characteristics of those large nodules with false negative cytology. METHODS: This was a retrospective case-log review in a tertiary referral hospital. All thyroid nodules subjected to Ultrasound (US)-guided FNAC by the Interventional Radiology department between December 2011 and November 2017 were included. Data on patient demographics, thyroid US features, cytology findings, and surgical histology were collected and analyzed. Sensitivity, specificity, and FNR were calculated based on FNAC results and final post-operative histology. Factors associated with a false negative result were analyzed using univariate and multivariate analyses. RESULTS: A total of 4982 nodules were studied, including 4419 < 4 cm and 563 ≥ 4 cm. Malignancy rates were similar in both groups. For nodules ≥ 4 cm, FNAC sensitivity was 40%, specificity 100%, and FNR 6.6% compared to 4.2% in nodules < 4 cm. Within malignant nodules, there was a significantly higher proportion of follicular and Hurthle cell carcinomas in nodules ≥ 4 cm. Amongst nodules ≥ 4 cm, multivariate analysis revealed male gender to be an independent predictor of FNR (OR 3.32; 95% CI 1.29-8.59). CONCLUSION: Larger nodules ≥ 4 cm have a similar malignancy rate as nodules < 4 cm, and FNAC FNR is low at 6.6%. Management of large thyroid nodules should be individualized based on their clinical, sonographic and cytological features rather than routine surgery.