Clinical Characteristics and Outcomes of Clinically Detected Versus Imaging-Detected Incidental Thyroid Cancer

The incidence of thyroid cancer has increased substantially, largely due to the widespread use of imaging that identifies incidental thyroid carcinomas. Whether these imaging-detected cancers differ from clinically detected cases remains uncertain. This study compared the clinicopathological features and long-term outcomes between clinically versus imaging-detected thyroid cancers.

Patients who underwent thyroidectomy for thyroid cancer at a tertiary referral center between 2010 and 2011 were retrospectively reviewed. Cases were categorized by detection mode as clinically or imaging detected. Demographic, pathological, treatment, and outcome data were analyzed, and survival was assessed using Kaplan-Meier estimates.

Among 384 patients, 98 (25.5%) had imaging-detected and 286 (74.5%) clinically detected cancer. Imaging-detected cases had smaller tumors, less extensive surgery and radioactive iodine therapy, lower nonstimulated thyroglobulin levels, and more favorable initial responses. In multivariable analysis, tumor size (P < .001) and lymph node metastasis (P = .039) were inversely associated with imaging detection, whereas Bethesda category VI cytology (P = .001) was a positive predictor. Five- and 10-year recurrence-free, disease-specific, and overall survival did not differ significantly between groups. Multivariable Cox analysis identified age (P < .001), multifocality (P = .033), lateral neck metastasis (P = .003), and high risk of structural recurrence (P = .004) as significant predictors of recurrence.

Clinically and imaging-detected thyroid cancers differ in clinicopathological profiles but show comparable long-term outcomes. These results suggest that early detection of thyroid cancer through imaging may not necessarily translate into a more favorable prognosis under risk-stratified management.