Active Surveillance for Low-risk Papillary Thyroid Carcinoma

Study Protocol of Extended Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Carcinoma (MAeSTro-EXP)

This is a multi-center, non-randomized, prospective observational cohort study aimed at establishing a cohort of low-risk papillary thyroid cancer patients with a maximum tumor diameter of 1.5 cm or less, consisting of an active surveillance group and an immediate surgery group.

The primary objective of this study is to evaluate the natural course of low-risk papillary thyroid cancer, specifically the progression rates of tumor size increase and the occurrence of local or distant metastasis. Ultimately, it is expected that establishing new criteria for active surveillance of low-risk papillary thyroid cancer in Korean patients will lead to a reduction in unnecessary surgical treatments, improving quality of life and decreasing national healthcare costs.

Inclusion Criteria:

• subjects over 18 years old with a thyroid nodule of ≤ 1.5 cm in maximum diameter and a Bethesda category V or VI diagnosis on cytopathology
• subjects without high-risk features, including lymph node (LN) metastasis, distant metastasis, signs or symptoms of invasion to the recurrent laryngeal nerve or trachea, Poorly differentiated cancer or variant with a poor prognosis, such as the tall cell, diffuse sclerosing, columnar cell, or solid variants.

Exclusion Criteria:

• subjects who are unable or unwilling to attend regular follow-ups..
• subjects with a diagnosis of benign, atypia of undetermined significance, suspicious for follicular neoplasm, or follicular neoplasm (Bethesda category II, III, or IV) based on Fine needle aspiration or, or benign, indeterminate by core needle biopsy.