Active surveillance of low-risk papillary thyroid carcinoma: a promising strategy requiring additional evidence

Abstract

Purpose: Papillary thyroid carcinoma (PTC), the most common malignant tumor of the thyroid, has been criticized as overtreated by some researchers in recent years. Active surveillance (AS) was first proposed at Kuma Hospital in 1993, and popularized in other institutes ever since. We provide a brief review of low-risk PTC active monitoring studies to date, and discuss the advantages of AS and limitations of existing studies.

Results: Most papillary thyroid microcarcinomas do not show significant growth or new lymph node metastasis in a 10-year AS period. Patients who undergo delayed surgery during AS generally have a good prognosis. Tumor progression correlates with age, calcification pattern, and Ki-67 positivity. Serum thyroid stimulating hormone concentration and pregnancy might also influence tumor progression in some studies.

Conclusion: Active surveillance for low-risk PTC has shown its safety and feasibility in certain populations. In the future, it is warranted to determine valuable tumor progression predictors and most suitable PTC patients for AS.

Keywords: Active surveillance; Low-risk; Observation; Papillary carcinoma; Thyroid.

Fig. 1

Progression of tumors during active surveillance. It shows the cumulative rate of tumor progression during AS at different follow-up points in several studies. All patients were followed up by ultrasound. The maximum tumor diameter increased ≥ 3 mm (a) and tumor volume increased ≥ 50% (b) during the follow-up period were used as the indicators of tumor enlargement