Purpose of review: Active surveillance is close follow-up of neoplasms, with predetermined intervention triggers. We systematically reviewed the published English language literature on primary active surveillance of low-risk papillary thyroid cancer (PTC).
Recent findings: We searched seven electronic databases (1980-2015), supplemented with a hand search. Two reviewers independently screened 1715 citations and reviewed 32 full-text papers, ultimately including two papers. Data were independently abstracted. There were two Japanese single-center, single-arm studies reporting on 1235 and 322 patients with PTC microcarcinoma (primary ≤1 cm in diameter) confined to the thyroid. Mean study follow-up was of 5.0 and 6.5 years, respectively. Disease triggers for thyroidectomy included progression of the primary tumor or incident metastatic disease. The rates of thyroidectomy were 15.5% (191/1235) and 8.7% (28/322) in respective studies. The incidence of primary tumor enlargement ≥3 mm in maximal diameter was 4.6% (58/1235) and 5.0% (16/322). The incidence of nodal metastases was 1.5% (19/1235) and 0.9% (3/322). There were neither reports of PTC-related death nor development of distant metastatic disease. Quality of life, psychosocial health, and economic outcomes were not reported.
Summary: In two Japanese single-arm studies, active surveillance of PTC microcarcinoma was relatively well tolerated; however, more long-term outcome research is needed.