Insights and clinical questions about the active surveillance of low-risk papillary thyroid microcarcinomas [Review]

Over 20 years ago, two Japanese institutions initiated an active surveillance policy for papillary microcarcinomas (PMCs) without high-risk features (such as clinical lymph node and distant metastases) and suspected trachea or recurrent laryngeal nerve invasion. Since the most recent American Thyroid Association (ATA) guidelines adopt active surveillance as a therapy option for low-risk PMCs, the number of institutions worldwide carrying out this policy can be expected to increase. However, before adopting an active surveillance strategy, some important clinical questions must be considered. In this review, conceivable clinical questions with our answers based on the present accumulation of low-risk PMC surveillance data are presented.