The effect of routine radiological reporting of thyroid incidentalomas on rates of thyroid needle biopsy, thyroid surgery and detection of thyroid malignancy

Abstract

Objective: This study looked at the effect of a changing radiology reporting policy to routinely review the thyroid gland where visible and report on any thyroid lesion, recommending further investigation as appropriate.

Context: Incidentaloma is a term used to describe a lesion found on imaging unrelated to the clinical issue under investigation. There is variability in the radiological reporting of thyroid incidentalomas and conflicting recommendations as to how these lesions should be managed.

Design: Data were collected retrospectively during a two-year period, including 12 months before and 12 months after the change in reporting policy and categorized according to whether the lesion under investigation was a thyroid incidentaloma or a symptomatic thyroid lesion.

Patients: All patients undergoing ultrasound-guided fine-needle aspiration cytology or core biopsy were included.

Measurements: The effects of the change in policy were analysed including rates of needle biopsy, rates of malignancy and subsequent surgical intervention.

Results: There was a 122% increase in thyroid incidentalomas undergoing needle biopsy, the majority of these were detected on computed tomography. The number of malignancies increased from 1 to 4 from year 1 to year 2. All patients were >35 years old. One patient had a positron emission tomography (PET)-detected cancer, two of four of the non-PET-detected malignancies were <1.5 cm.

Conclusion: This study posits that routine radiological reporting of thyroid incidentalomas, with further investigation when clinically appropriate, is warranted. The results suggest that lesion size and CT characteristics are not reliable criteria to triage patients for investigation/biopsy.

Keywords: incidental findings; technical report; thyroid cancer; thyroid nodule.