Reporting of Incidental Thyroid Nodules on Chest Computed Tomography and the Impact on Nodule Evaluation: A Retrospective Cohort Study.

Abstract

Introduction: Thyroid incidentalomas are frequently identified thyroid nodules viewed on nonthyroid dedicated imaging studies. Clinical guidelines recommend evaluation of all thyroid incidentalomas to risk stratify for cancer. This study examined how thyroid incidentalomas are reported on chest computed tomography (CT) and determined the association of reporting location with likelihood of evaluation and risk of long-term outcomes. Methods: Retrospective cohort of 1460 previously identified Veterans with thyroid incidentalomas on chest CT from a single VA institution between 1995 and 2016. Reporting of the incidentaloma was categorized as either in the body of the report alone or in the impression. Demographic data, vital status, thyroid ultrasound, endocrinology consult, thyroid nodule fine needle aspiration, thyroid surgery, thyroid cancer diagnosis, and death from thyroid cancer were abstracted. Results: Among the 1460 Veterans (mean age 70.4 years and 94.9% male) in the cohort, 707 incidentalomas (48.4%) were reported in the impression and 753 (51.6%) were reported in the body section. Veterans with thyroid incidentalomas reported in the impression versus body were significantly more likely to be evaluated within 6 months (35.5% vs. 5.1%; p ≤ 0.001), 12 months (38.5% vs. 6.5%; p ≤ 0.001), and at any time during the follow-up period (47.8% vs. 13.2%; p ≤ 0.001). Veterans with thyroid incidentalomas reported in the impression versus body were more likely to undergo thyroidectomy (18 [2.6%] vs. 6 [0.8%]; p = 0.009), but there was no difference in the proportion of Veterans diagnosed with thyroid cancer (11 [1.6%] vs. 6 [0.8%]; p = 0.18), thyroid-cancer related mortality (4 [0.6%] vs. 1 [0.1%]; p = 0.16), or all-cause mortality (63.2% vs. 66.5%; p = 0.19). Conclusions: Thyroid incidentalomas on chest CT are inconsistently reported and often receive no subsequent evaluation. The location of reporting affects whether clinical evaluation is performed, yet reporting does not affect the proportion of Veterans who died of any cause and may have little effect on the proportion of Veterans who received a diagnosis of thyroid cancer or died from thyroid cancer. These findings suggest that the guideline recommendation to evaluate all thyroid incidentalomas should be reevaluated.