Over recent decades, the incidence of thyroid cancer has increased substantially worldwide, with papillary thyroid carcinoma (PTC) accounting for most new cases (1). However, this increase has not been paralleled by higher disease-specific mortality, indicating that the surge largely reflects improved detection rather than a true rise in clinically significant disease (2, 3). The widespread use of high-resolution imaging has enabled the frequent identification of small, asymptomatic thyroid carcinomas that would likely have remained indolent (4, 5). In countries such as South Korea, low-cost thyroid ultrasonography (approximately $30–50) is often added to national cancer screening, further contributing to the sharp rise in incidental detections (6).

This phenomenon of overdiagnosis has become a major public health concern. The World Health Organization’s International Agency for Research on Cancer and others have attributed much of the rising incidence in high-income countries to incidental findings from routine ultrasound screening (7, 8). Sociodemographic factors, including higher education and income, are associated with greater diagnostic intensity (9, 10). Nevertheless, these detection trends have not improved mortality outcomes, leading the U.S. Preventive Services Task Force to recommend against routine screening for asymptomatic adults (11).

Although active surveillance is an option for selected patients with low-risk microcarcinomas, surgical intervention remains the predominant approach. Communicating to patients that immediate surgery may not improve outcomes remains challenging, and many still undergo potentially avoidable operations with attendant risks such as vocal cord paralysis, hypoparathyroidism, and lifelong levothyroxine dependence, in addition to increased healthcare costs (12).

Despite growing recognition of overdiagnosis, few studies have directly compared the clinicopathological features and outcomes of imaging-detected versus clinically detected thyroid cancers, a distinction frequently encountered in clinical practice. Moreover, the prognostic implication of the mode of detection remains controversial. While some studies suggest that symptomatic thyroid cancers exhibit more aggressive biological behavior and poorer outcomes, others indicate that symptomatic presentation carries a similar long-term prognosis (13, 14, 15). Addressing this gap, this study aims to elucidate the clinical and prognostic differences between these groups by providing 10-year follow-up data, thereby offering evidence to refine risk assessment, patient counseling, and disease management.