Active surveillance of nodal metastasis in differentiated thyroid carcinoma: a systematic review and meta-analysis.

PURPOSE: Cervical lymph nodes (LN) represent the most common site of recurrence in differentiated thyroid cancer (DTC), frequently requiring repeated interventions that contribute to increase morbidity to a usually indolent disease. Data on active surveillance (AS) of nodal metastasis are limited. Therefore, we performed a systematic review and meta-analysis to evaluate AS in nodal metastasis of DTC patients.

METHODS: MEDLINE, EMBASE, and Cochrane databases were searched up to July 2023 for studies including DTC patients with metastatic LN who were followed up with AS. The primary outcome was disease progression, according to the study's definition. Additional outcomes were LN enlargement ≥3 mm, occurrence of new cervical metastasis, and conversion from AS to surgical treatment.

RESULTS: The search identified 375 studies and seven were included, comprising 486 patients with metastatic nodal DTC. Most were female (69.5%) and had papillary thyroid cancer (99.8%). The mean AS follow-up ranged from 28-86 months. Following each study's definition of progression, the pooled incidence was 28% [95% confidence interval (CI), 20-37%]. The pooled incidence of LN growth ≥ 3 mm was 21% [95% CI, 17-25%] and the emergence of new LN sites was 19% [95% CI, 14-25%]. Combining growth of 3 mm and the emergence of new LN criteria, we found an incidence of 26% [95% CI, 20-33%]. The incidence of neck dissection during AS was 18% [95% CI, 12-26%].

CONCLUSIONS: AS seems to be a suitable strategy for selected DTC patients with small nodal disease, avoiding or postponing surgical reintervention.

PROSPERO REGISTRATION: CRD42023438293.