ACR TI-RADS Recommendations: A Call to Contextualize Radiologists’ Recommendations for Thyroid Nodules With the Clinical Scenario

The American College of Radiologists (ACR) incidental findings and Thyroid Imaging Reporting and Data System (ACR TIRADS) committees have provided guidance for reporting findings and providing recommendations for the management of patients with thyroid nodules, and these interventions have significantly reduced performance of unnecessary thyroid biopsies.^{1 2} ACR guidance spans from incidental thyroid nodules detected on cross-sectional imaging and positron emission tomography, to categorization according to thyroid cancer risk for thyroid nodules evaluated on ultrasound with ACR TIRADS.^{1 2} Evaluation and treatment of the thyroid nodule is frequently not the primary concern of the patient or of the clinician when it is discovered.^{3 4} Thyroid nodule evaluation may have been born out of testing unrelated to the thyroid, and often are ordered by primary care clinicians who are providing care for multiple other issues. Therefore, clinicians are quite appreciative of specific recommendations for thyroid nodule management according to imaging results.

However, the phrasing of recommendations in the absence of detailed clinical context can lead to mismanagement of some patients, especially when the clinical context of the patient (risk factors for thyroid cancer, comorbidities or previously performed testing) might lead to management plans contrary to the TIRADS recommendations. In other words, structured reporting can hinder patient-centered care if the report’s recommendation stands in contrast with the clinician’s recommendation in the context of a specific patient’s medical history. In this article we offer scenarios in which ACR TIRADS recommendations can conflict with patient centered care, and offer suggestions on how radiologists can help referring providers improve the quality of care of patients with thyroid nodules.

Thyroid nodule ultrasound risk-stratification systems are a crucial tool for patient care

The incidence of thyroid cancer diagnosis has dramatically increased during the last few decades, in part due to an enhanced detection and evaluation of thyroid nodules.⁴ For many patients, the incidental discovery of a thyroid nodule starts them on a path towards diagnosis of a clinically indolent thyroid cancer (thyroid cancer overdiagnosis).⁴ Possible strategies to mitigate thyroid cancer overdiagnosis include recommendations against routine screening for thyroid cancer with ultrasound and avoidance of thyroid ultrasound use for the evaluation of abnormal thyroid laboratory result in the absence of a palpable neck mass.^{4 5} Furthermore, several thyroid ultrasound stratification systems have been developed to provide a structure to sonographic risk stratification for thyroid cancer based on presence or absence of suspicious features; these include the American Thyroid Association clinical practice guidelines and the ACR TIRADS.^{2 4} These systems include a recommendation for biopsy of thyroid nodules based on thyroid nodule cancer risk and size, and can help support patient care.² In fact, the implementation of ACR TIRADS reduces the rate of benign biopsies and overall biopsy recommendation rates compared to no risk stratification system and results in decreased variability in management recommendations.⁶ Using ACR TIRADS in a structured report also ensures relevant imaging findings are included and facilitates communication among clinicians supporting clinical decision-making.⁷

Risk to over-reliance of radiological recommendations for thyroid biopsy

Thyroid ultrasound reports are a key clinical tool in the care of patients with thyroid nodules but clinical decision-making includes considerations of other risk factors for thyroid cancer and the patient’s situation (Table 1). Commonly, consideration of these clinical variables may override recommendations based solely on imaging findings and where feasible they could be collected by the technologist during the imaging period or in a form completed by the patient while waiting for their appointment (similar to the approach of bone density reports). These considerations are important, given that a previous history of thyroid biopsy or laboratory evidence of hyperthyroidism, can directly inform the recommendations derived from ultrasound assessment.

Table 1.

Clinical variables that can help contextualize ACR TIRADS management recommendations

Age

Comorbidities and competing causes of death (e.g. active malignancy, advanced heart failure)

History of neck radiation

Family history of thyroid cancer

Functional status

Thyroid status (e.g. TSH levels)

Previous thyroid biopsy

Patient’s values and preferences (e.g. discomfort with uncertainty, tolerance for invasive procedures)

Healthcare access and ability to continue follow up

^*Variables required to contextualized ACR-TIRADS management recommendations include those that: 1) directly impact thyroid cancer risk and 2) provide in depth understating of the patient’s situation beyond thyroid cancer risk.

A more complex scenario is when the radiologist identifies a suspicious nodule, but the recommendation for biopsy may not be appropriate in the context of a patient’s clinical history. For example, an older patient with advanced lung cancer is incidentally found to have a 2 cm thyroid nodule. Thyroid ultrasonography identifies an ACR TIRADS TR4 nodule, which carries a risk of malignancy of 10–20%.^{2 4} A fine needle aspiration is recommended by ACR TIRADS. What happens next, to a large extent, depends on who receives the sonography report. We frequently see patients in clinical practice who proceeded with a biopsy, and a subsequent thyroidectomy, based on the downstream effects of the imaging report and recommendations. Although the recommendations for reporting incidental thyroid nodules takes into context life expectancy, ACR TIRADS is context blind.^{1 2} Given our example patient’s overall prognosis from his much more aggressive lung cancer, a biopsy should not be recommended. Of course the best practice, would be that the provider does not reflexively order the ultrasound in such a patient, but not all providers are aware of such guidelines or the natural history of thyroid cancer.

Although clinicians may judge the radiologist recommendations as inappropriate and not act on them, evidence suggests that radiologists recommendation have a significant impact in clinical decision making.³ In an analysis of 141 thyroid nodules in 129 patients with sub-centimeter suspicious thyroid nodules (nodules for which biopsy is unlikely to be beneficial and is not recommended), one of the strongest predictors of nodule biopsy were radiology recommendations for biopsy regardless of limited life expectancy and patients’ age.³ This finding suggests that radiologists’ recommendations are highly regarded by clinicians and that it may be difficult to contradict a recommendation for a more aggressive approach once it has already been documented in the medical record.

In addition to competing comorbidities, multiple other factors impact the decision to perform biopsy that go beyond thyroid cancer risk: functional status, patient values and preferences, access to care among others (Table 1). Furthermore, in light of patient access to medical reports, wording of the impression and recommendation of ultrasound reports can significantly influence a patient’s expectations or unnecessarily cause fear or anxiety.⁸

Moving forward: contextualizing the need for thyroid biopsy

Now that we have excellent thyroid nodule risk-stratification systems that reliably predict and effectively communicate risk of thyroid cancer, what next steps can we take towards implementing these tools in a patient-centered model of care? Of course, the ideal situation would involve the integration of clinically-relevant patient history with the radiographic assessment at the point of evaluation, with generation of a patient-centered recommendation for further steps. Practically, however, this is difficult to achieve and may not optimally utilize the expertise of our radiologists. Nonetheless, patient-centered care can be promoted by integration of important clinical variables to improve thyroid cancer risk assessment of a thyroid nodule and considering the patient’s situation in the decision making process at the time of thyroid ultrasound assessment.

We envision a thyroid nodule reporting system that fluidly incorporates the perspectives of the radiologist, the treating clinician, and the patient and supports patient centered-care. In other words, the system continues to task our colleagues in radiology with the critical role of conducting a comprehensive sonographic evaluation of the neck, while providing language that is practical enough for the clinician to incorporate into clinical context, and phrased in a way that is not intimidating to patients.

We suggest the radiology report should be structured and descriptive, but there should be attention to how management recommendations are phrased. Instead of stating “Recommend fine needle aspiration biopsy”, radiologists would avoid conflicts in best care with a classifier such as, “Based solely on ultrasound findings, fine needle aspiration biopsy can be considered”. This rather simple modification to the current structure of ACR TIRADS report, provides clinician with clear, structured, informative and actionable guidance based on expert sonographic evaluation of the thyroid nodules. Moreover, this wording, is an invitation for clinicians to contextualize the ultrasound findings. This contextualization may be easier to accomplish in a specialty care setting where there is more time to allocate to the management of a thyroid nodule, but is an important reminder for contextualization for general practice clinicians who may be pulled in many other clinical directions. Furthermore, given increasing electronic access to medical records, a mention of contextualization may alert patients to the fact that more than one management option may be possible (e.g. biopsy or follow up), depending on clinical context, and may reduce the expectation of a particular management option.

We believe this approach facilitates the collaboration of multi-disciplinary teams, opens the door for patient-centered and situation-centered medical decision-making, and can help patients better understand recommendations. Thyroid nodule risk-stratification significantly improves thyroid cancer risk assessment and can further support patient-centered care by encouraging clinicians to contextualize this risk by incorporating variables that affect the risk for thyroid cancer, as well as those that provide an understanding of the patient’s situation. We must now embark on utilizing the evidence-based approach and putting it into a context individualized to specific patient situations.