The increased utilization of computed tomography (CT) has led to a higher detection rate of thyroid incidentalomas. Currently, there are no widely agreed-upon guidelines for managing these incidentalomas. This study aims to investigate the prevalence, follow-up practices, and malignancy rates of thyroid incidentalomas detected by CT.
Methods:
We conducted a comprehensive search of PubMed, Embase, and Cochrane databases to identify relevant studies published before April 12, 2024 (PROSPERO #42024535501). Studies reporting on the prevalence, follow-up, and risk of malignancy (ROM) of thyroid incidentalomas detected by CT were included. Combined outcomes were analyzed using pooled proportion with a random-effects model. The risk of bias was assessed using the Cochrane risk-of-bias tool for randomized trials (RoB 2) and the Newcastle–Ottawa Scale tool. Subgroup analyses were conducted based on characteristics including size of the incidentaloma, CT area, and age of the study population.
Results:
Thirty-eight studies involving 195,959 patients were included in the prevalence analysis, revealing a prevalence of thyroid incidentalomas on CT of 8.3% (confidence interval [CI], 7.4–9.3). The prevalence was higher in neck CT (16.5%, CI, 11.0–22.1) compared with chest CT (6.6%, CI, 5.3–7.9). Multiple incidentalomas were found in 27.0% (CI, 12.9–41.1) of patients. Of the nodules, 46.3% (CI, 32.3–60.3) were ≥1 cm, and 28.6% (CI, 19.9–37.3) were ≥1.5 cm. Thyroid ultrasounds, biopsies, and surgeries were performed in 34.9% (CI, 26.1–43.7), 28.4% (CI, 19.9–36.9), and 8.2% (CI, 2.1–14.4) of cases, respectively. Additionally, 25 studies with 6272 patients reported a ROM of 3.9% (CI, 3.0–4.9) for thyroid incidentalomas detected on CT. A higher ROM was observed in incidentalomas ≥1 cm (11.7%, CI, 3.9–19.4) and ≥1.5 cm (24.9%, CI, 0–52.7) compared with those <1 cm (0.1%, CI, 0–0.8) and <1.5 cm (0%, CI, 0–0.2).
Conclusions:
Most thyroid incidentalomas identified on CT are benign. Implementing a collaborative protocol between radiologists and thyroid specialists to manage high-risk thyroid incidentalomas can ensure appropriate follow-up and optimal patient care.
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