Low-risk papillary microcarcinoma of the thyroid: A review of active surveillance trials

摘要

Papillary microcarcinoma (PMC) is defined as papillary thyroid carcinoma (PTC) measuring ≤1 cm. This definition of PMC does not depend on whether or not high-risk features such as lymph node metastasis and/or distant metastasis are present. Therefore, ‘PMC’ covers a broad range of biological characteristics. The prognosis of patients with PMC can be poor if they have high-risk features such as clinical node metastasis, distant metastasis, or significant extrathyroid extension such as to the trachea and recurrent laryngeal nerve, even if these patients undergo immediate and sufficient surgery. In contrast, PMCs without any high-risk features (i.e., low-risk PMCs) are generally an indolent disease, and most of them do not grow or they grow very slowly.