Cost effectiveness of immediate biopsy versus surveillance of intermediate-suspicion thyroid nodules

From Bench-to-Bedside: How Artificial Intelligence is Changing Thyroid Nodule Diagnostics, a Systematic Review

CONTEXT

Use of artificial intelligence (AI) to predict clinical outcomes in thyroid nodule diagnostics has grown exponentially over the past decade. The greatest challenge is in understanding the best model to apply to one's own patient population, and how to operationalize such a model in practice.

EVIDENCE ACQUISITION

A literature search of PubMed and IEEE Xplore was conducted for English-language publications between January 1, 2015 and January 1, 2023, studying diagnostic tests on suspected thyroid nodules that used AI. We excluded articles without prospective or external validation, nonprimary literature, duplicates, focused on nonnodular thyroid conditions, not using AI, and those incidentally using AI in support of an experimental diagnostic outside standard clinical practice. Quality was graded by Oxford level of evidence.

EVIDENCE SYNTHESIS

A total of 61 studies were identified; all performed external validation, 16 studies were prospective, and 33 compared a model to physician prediction of ground truth. Statistical validation was reported in 50 papers. A diagnostic pipeline was abstracted, yielding 5 high-level outcomes: (1) nodule localization, (2) ultrasound (US) risk score, (3) molecular status, (4) malignancy, and (5) long-term prognosis. Seven prospective studies validated a single commercial AI; strengths included automating nodule feature assessment from US and assisting the physician in predicting malignancy risk, while weaknesses included automated margin prediction and interobserver variability.

CONCLUSION

Models predominantly used US images to predict malignancy. Of 4 Food and Drug Administration-approved products, only S-Detect was extensively validated. Implementing an AI model locally requires data sanitization and revalidation to ensure appropriate clinical performance.

Cost-Effectiveness of the ACR TIRADS Compared to the ATA 2015 Risk Stratification Systems in the Evaluation of Incidental Thyroid Nodules

RATIONALE AND OBJECTIVES

Thyroid nodules are a common incidental imaging finding and prone to overdiagnosis. Several risk stratification systems have been developed to reduce unnecessary work-up, with two of the most utilized including the American Thyroid Association 2015 (ATA2015) and the newer American College of Radiology Thyroid Imaging, Reporting and Data System (TIRADS) guidelines. The purpose of this study is to evaluate the cost-effectiveness of the ATA2015 versus the TIRADS guidelines in the management of incidental thyroid nodules.

METHODS

A cost-utility analysis was conducted using decision tree modeling, evaluating adult patients with incidental thyroid nodules < 4 cm. Model inputs were populated using published literature, observational data, and expert opinion. Single-payer perspective, Canadian dollar currency, five-year time horizon, willingness to pay (WTP) threshold of $50,000, and discount rate of 1.5% per annum were utilized. Scenario, deterministic and probabilistic sensitivity analyses were performed. The primary outcome was the incremental cost-effectiveness ratio (ICER) expressed as incremental cost per quality-adjusted life year (QALY) gained.

RESULTS

For the base case scenario, TIRADS dominated the ATA2015 strategy by a slim margin, producing 0.005 more QALYs at $25 less cost. Results were sensitive to the malignancy rate of biopsy and the utilities of a patient with a benign nodule/subclinical malignancy or under surveillance. Probabilistic sensitivity analysis showed that TIRADS was the more cost-effective option 79.7% of the time.

CONCLUSION

The TIRADS guidelines may be the more cost-effective strategy by a small margin compared to ATA2015 in most scenarios when used to risk stratify incidental thyroid nodules.

An economic evaluation of fine-needle cytology as the primary diagnostic tool in the diagnosis of lymphadenopathy

Fine-needle aspiration cytology (FNAC) is commonly used to obtain a pre-surgical pathological diagnosis in many organs, but its cost-effectiveness in lymphadenopathy has not been studied yet. We calculated the cost and diagnostic accuracy of a diagnostic algorithm that uses FNAC as a first-line procedure and compared it to a purely surgical approach in 545 consecutive lymphadenopathies. In 74% of the cases, FNAC alone can obtain a sufficiently detailed diagnosis, avoiding the surgical biopsy. In doing so, the average cost of diagnosis is cut to less than one-third, the patient avoids an invasive procedure and the diagnosis is reached earlier. In conclusion, the systematic use of lymph node-FNAC in the initial assessment of lymphadenopathy is clinically and economically advantageous as it avoids surgical biopsies in cases where cytology can suffice.

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.

A Case-Based Comparison of the American Thyroid Association and Thyroid Imaging Reporting & Data System Guidelines

Thyroid nodules are a common clinical finding. Approximately 4-7% of the population have a palpable nodule on physical exam,1 while up to 70% of the population have a nodule detected incidentally on ultrasound.2 The vast majority of nodules are benign, however, approximately 5-13% of thyroid nodules detected on imaging are at risk of malignancy.3 Some malignant nodules, especially those smaller than 1 cm, can exhibit indolent behavior and do not require aggressive treatment.4 Therefore, thyroid nodules need to be accurately assessed to avoid overdiagnosis and overtreatment of nodules which would not otherwise affect patient morbidity. The American Thyroid Association (ATA) addressed this challenge by developing a set of ultrasound pattern-based guidelines for thyroid nodule management in 2009, which were updated in 2015.5 Other societies have since published similar guidelines, such as the Thyroid Imaging Reporting & Data System (TI-RADS) by the American College of Radiology in 2017. TI-RADS was similarly intended to risk-stratify nodules based on ultrasound appearance, but uses a points-based approach. The purpose of this review is to provide an overview of thyroid nodule evaluation and management through a case-based comparison using the ATA and TI-RADS guidelines.

The Concept of Economic Evaluation and Its Application in Thyroid Cancer Research

Economic evaluation is a type of comparative analysis between interventions in terms of both their resource use and health outcomes. Due to the good prognosis of thyroid cancer (TC), the socioeconomic burden of TC patients post-diagnosis is increasing. Therefore, economic evaluation studies focusing on TC are recommended. This study aimed to describe the concept and methods of economic evaluation and reviewed previous TC studies. Several previous studies compared the costs of interventions or evaluated recurrence, complications, or quality of life as measures of their effectiveness. Regarding costs, most studies focused on direct costs and applied hypothetical models. Cost-minimization analysis should be distinguished from simple cost analysis. Furthermore, due to the universality of the term "cost-effectiveness analysis" (CEA), several studies have not distinguished CEA from cost-utility analysis; this point needs to be considered in future research. Cost-benefit analyses have not been conducted in previous TC research. Since TC has a high survival rate and good prognosis, the need for economic evaluations has recently been pointed out. Therefore, correct concepts and methods are needed to obtain clear economic evaluation results. On this basis, it will be possible to provide appropriate guidelines for TC treatment and management in the future.

Can Diffusion-Weighted MR Imaging Be Used as a Tool to Predict Extrathyroidal Extension in Papillary Thyroid Carcinoma?

RATIONALE AND OBJECTIVES

To evaluate whether quantitative diffusion-weighted MR imaging (DWI) with multi-b values can be used as a tool to predict the aggressiveness by using the histological feature of extrathyroidal extension (ETE) in papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

238 patients were pathologically confirmed as PTCs underwent preoperative multi-b value DWI (300, 500, and 800 s/mm²) between January 2015 and December 2017. The patients were divided into three groups according to the degree of ETE: without ETE, minimal ETE, and extensive ETE. The apparent diffusion coefficients (ADCs) were evaluated for three different b values (b = 300 s/mm², b = 500 s/mm², and b = 800 s/mm²). The ADC values of the groups with and without ETE, minimal and extensive ETE were compared. The diagnostic relevance of the ADC values in terms of predicting ETE was compared using a receiver operating characteristic analysis. Differences between the areas under the curves (AUCs) were compared by using a Delong test.

RESULTS

PTCs with ETE had significantly lower ADC₃₀₀, ADC₅₀₀ and ADC₈₀₀ values than PTCs without ETE (p = 0.001, p < 0.001, and p < 0.001, respectively). The AUC of the mean ADC₅₀₀ value (0.905) was higher than that of the ADC₃₀₀ and ADC₈₀₀ values (0.607 and 0.770, respectively) in differentiating ETE from without ETE (p < 0.001). The cut-off value of ADC₅₀₀ to discriminate PTCs with and without ETE was determined at 1.407 × 10^-3 mm²/s, with sensitivity of 80.7%, specificity of 86.7%, and an AUC of 0.905.

CONCLUSION

The ADC value can be demonstrated an effective tool for evaluating the aggressiveness with the histological feature of ETE in PTC. In particular, ADC value at b = 500 s/mm² showed the best performance for noninvasive preoperative evaluation of ETE.

Factors affecting thyroid nodule fine needle aspiration non-diagnostic rates: a retrospective association study of 1975 thyroid biopsies

Background

Thyroid nodules are common in clinical practice, and it is important to distinguish benign nodules, the vast majority, from malignant ones. Non-diagnostic (ND) samples have the potential to delay or mis-diagnose or lead to unnecessary surgeries, and it is important to examine what factors influence the ND rate. Prior literature has suggested that the impact of bedside cytology on ND rate is dependent on the initial adequacy rate, whereby higher ND rates benefit most from bedside cytology. We aim to compare the impact of bedside adequacy review between specialist groups who perform high volume thyroid biopsies with low initial ND rates.

Methods

We reviewed the cytopathology results of 1975 thyroid nodule FNAs performed between January 1, 2017 to December 31, 2017 in a multi-centre Canadian city, and the corresponding histopathology reports of 340 resected nodules. Descriptive variables were used to describe the data along with chi-squared testing and univariate logistic regression.

Results

The FNA biopsies were performed by three different speciality groups, which differed by procedural volume: radiology performed the most at 1171, pathology performed 655 and surgery performed 103. We could not define the operator for 45 of the nodules. The ND rate was lowest in the speciality groups with highest procedural volume, 3.4 % in pathology and 8.3 % in radiology, compared to 37.9 % in surgery (p < 0.001). Completion of bedside cytology rapid onsite evaluation (ROSE) significantly reduced the ND rate from 16.7 to 4.2 % for all samples (p < 0.001). When ROSE was compared with non-ROSE within a high procedural group (radiology), it further reduced the ND rate from 12.5 to 5.1 % (p < 0.001). Of the 340 resected nodules, 10.7 % (18) were in the ND category, of which 28 % (5/18) of these were found to be malignant (4 papillary carcinoma and 1 lymphoma).

Conclusions

The results from this study demonstrate that thyroid FNAs performed with bedside ROSE can significantly reduce the ND rate compared with non-ROSE, even in experienced groups with low initial ND rates. It is therefore imperative that care providers managing patients with thyroid nodules ensure that thyroid FNAs are referred to specialized individuals/groups who do high volume, and ideally with the use of bedside ROSE, whether provided by a cytotechnologist or a pathologist.

Analysis of Malignant Thyroid Nodules That Do Not Meet ACR TI-RADS Criteria for Fine-Needle Aspiration

OBJECTIVE. Compared with other guidelines, the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) has decreased the number of nodules for which fine-needle aspiration is recommended. The purpose of this study was to evaluate the characteristics of malignant nodules that would not be biopsied when the ACR TI-RADS recommendations are followed. MATERIALS AND METHODS. We retrospectively reviewed a total of 3422 thyroid nodules for which a definitive cytologic diagnosis, a definitive histologic diagnosis, or both diagnoses as well as diagnostic ultrasound (US) examinations were available. All nodules were categorized using the ACR TI-RADS, and they were divided into three groups according to the recommendation received: fine-needle aspiration (group 1), follow-up US examination (group 2), or no further evaluation (group 3). RESULTS. Of the 3422 nodules, 352 were malignant. Of these, 240 nodules were assigned to group 1, whereas 72 were assigned to group 2 and 40 were included in group 3. Sixteen of the 40 malignant nodules in group 3 were 1 cm or larger, and, on the basis of analysis of the sonographic features described in the ACR TI-RADS, these nodules were classified as having one of five ACR TI-RADS risk levels (TR1-TR5), with one nodule classified as a TR1 nodule, eight as TR2 nodules, and seven as TR3 nodules. If the current recommendation of no follow-up for TR2 nodules was changed to follow-up for nodules 2.5 cm or larger, seven additional malignant nodules and 316 additional benign nodules would receive a recommendation for follow-up. If the current size threshold (1.5 cm) used to recommend US follow-up for TR3 nodules was decreased to 1.0 cm, seven additional malignant nodules and 118 additional benign nodules would receive a recommendation for follow-up. CONCLUSION. With use of the ACR TI-RADS, most malignant nodules that would not be biopsied would undergo US follow-up, would be smaller than 1 cm, or would both undergo US follow-up and be smaller than 1 cm. Adjusting size thresholds to decrease the number of missed malignant nodules that are 1 cm or larger would result in a substantial increase in the number of benign nodules undergoing follow-up.

Intranodular Vascularity May Be Useful in Predicting Malignancy in Thyroid Nodules with the Intermediate Suspicion Pattern of the 2015 American Thyroid Association Guidelines

The aim of the study described here was to determine whether vascularity patterns on Doppler ultrasonography (US) differentiate benign and malignant thyroid nodules with the intermediate suspicion pattern based on the 2015 American Thyroid Association guidelines. A total of 411 benign or malignant thyroid nodules from 406 patients with intermediate-suspicion US features were retrospectively collected. Univariate and multivariate logistic regression analyses with the generalized estimating equation were used to identify factors predicting malignancy, and odds ratios with 95% confidence intervals were calculated. The vascularity patterns significantly differed between the benign (353 of 411, 85.9%) and malignant (58 of 411, 14.1%) nodules (p = 0.005). Only intranodular vascularity was significantly associated with malignancy on univariate analysis (p = 0.006) and was an independent predictor of malignancy on multivariate analysis (p = 0.004). In conclusion, intranodular vascularity on Doppler US may be useful for predicting malignancy in thyroid nodules with the intermediate-suspicion pattern.

US-based risk stratification "guidelines" for thyroid nodules: Quō Vādis?

PURPOSE

This rapid scoping review addresses the commentary titled the ACR TI-RADS™: An Advance in the Management of Thyroid Nodules or Pandora's Box of Surveillance? suggesting that the 2017 American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS™-2017) adds to a plethora of existing guidelines, incorporates an inconsistent lexicon, and potentially contradicts recommendations.

MATERIALS AND METHODS

The author performed a rapid scoping review using a combination of English keywords to identify and review peer reviewed articles contained in electronic databases (e-databases) comparing 2 or more guidelines for managing adult thyroid nodules (GMTNs) with (UGMTNs) and without (non-UGMTNs) ultrasound. E-databases included Medline (PubMed), EBSCO, Google, and Google Scholar published (2010-2019).

RESULTS

The search returned 28 articles, where the author identified 12 different guidelines. Most articles evaluated diagnostic performance (N = 26), not quality (N = 2) measures. The most commonly reviewed UGMTNs were in descending order ATA-2015, ACR TI-RADS™-2017, South Korean, and EU TI-RADS. No article reviewed all GMTNs or identified a generally accepted UGMTNs or non-UGMTNs. Primary origin continents were: North America (U.S.A), Asia (Japan, South Korea, Thailand), Europe (France, Italy, U.K.), and South America (Chile).

CONCLUSION

A plethora of UGMTNs may exist. No guideline enjoys general acceptance and evaluations of performance and quality vary.