Preoperative Computed Tomography Changes Surgical Management for Clinically Low-Risk Well-Differentiated Thyroid Cancer

Abstract

BACKGROUND: In the current guidelines for differentiated thyroid cancer (DTC), computed tomography (CT) of the neck has a limited role. The authors hypothesized that adding CT to the workup of clinically low-risk DTC size 4 cm or smaller changes the surgical management for a portion of patients due to detection of clinically significant lymph node metastases not located by ultrasound of the neck. METHODS: A prospective cohort of DTC patients at an academic referral center between 2012 and 2016 was reviewed. All the patients with fine-needle aspiration cytopathology results suspicious for malignancy or malignant tumor (Bethesda category 5 or 6, respectively) underwent CT before surgery. Clinically low-risk DTC patients were selected if they had a tumor diameter of 4 cm or less and no evidence for local invasion or suspicious lymph nodes seen on ultrasound. Outcomes focused on alteration of the surgical plan based on CT and correlation with pathology. RESULTS: The CT findings for 25 (22.5%) of 111 patients with clinically low-risk DTC led to a change in surgical management. Of these 25 patients, 16 (14.4% of the entire cohort) benefited due to the removal of clinically significant lymph node disease not seen on ultrasound. Categorization of the group that had a change in management showed that 6 (85.7%) of 7 lateral neck dissections and 10 (55.6%) of 18 central neck dissections (CND) harbored metastatic nodes larger than 2 mm. CONCLUSIONS: In the group with clinically low-risk DTC, CT changed surgical management for a substantial number of the patients with clinically significant nodal disease not detected by ultrasound. This highlights the fact that in certain practice settings, adding CT to the preoperative staging may be favorable for the detection of nodal metastasis.