Active Surveillance of Papillary Thyroid Microcarcinoma: A Mini-Review from Korea (Endocrinol Metab 2017;32:399-406, Tae Yong Kim et al.).

We read with interest the paper by Prof. Kim and Shong, entitled “Active surveillance of papillary thyroid microcarcinoma: a mini-review from Korea,” published in the December 2017 issue of Endocrinology and Metabolism (Seoul) [1]. Overdetection and overtreatment are common in many areas of modern medicine. Several steps are needed to decrease overdetection: elderly subjects who are unlikely to benefit should not be screened, biopsies should not be performed without a compelling reason, the screening interval should be stratified by risk, and the focus should be on screening subjects at high risk for disease progression [12]. Treatment should be tailored to the biological characteristics of the tumor and the patient's characteristics, and active surveillance (AS) should be offered to eligible patients with low-risk tumors, especially small-volume disease, as the first step in management [123]. Many low-grade papillary microcarcinomas are unlikely to progress to clinical symptoms, and pose a limited risk of death if left untreated [2]. Several AS criteria have been suggested for delayed treatment [4]. Although the upgrading and/or upstaging of cancer is a limitation of AS, recent reports have shown low rates of cancer-specific mortality [4].

Nevertheless, the long-term safety of AS depends on the clinician's ability to initiate timely delayed interventions in those who need them, and to avoid overtreatment in those who do not.

In contrast, with immediate surgery, early-stage tumors are excised at a more treatable stage, fewer patients develop metastatic disease, less extensive surgery (hemithyroidectomy) is more likely, and minimally invasive approaches are applied; additionally, there is no need for lifelong thyroid replacement therapy, consistent follow-up, or risk factor assessments, and low-dose or no radioactive iodine administration is needed [5]. The increasing use of minimally invasive surgery, including robot-assisted surgery, has contributed to better functional outcomes [5]. Well-designed long-term randomized studies will be required to compare the benefits of AS and immediate, minimally invasive hemithyroidectomy.

Thank you for the opportunity to present our reflections on this paper.