The prognostic significance of lymph node metastases characteristics in papillary thyroid carcinoma: a scoping review

Despite neck lymph node metastases occurring commonly in cases of papillary thyroid carcinoma (PTC), there has remained controversy regarding the thresholds that should be used for lymph node characteristics in predicting PTC recurrence risk.
This scoping review explored the prognostic significance of lymph node characteristics in predicting risk of PTC recurrence. Following the PRISMA guidelines, the PubMed, Embase, and Web of Science databases were searched and supplemented by hand searching reference lists to identify articles published from database inception until October 2024. A total of 172 studies were included. Most studies had a retrospective cohort design and were reported from South Korea, Japan, and China. In general, an increased number of metastatic lymph nodes (commonly >5), presence of extranodal cancer extension, larger size of metastatic lymph nodes (commonly >3 cm), higher lymph node ratio (commonly ≥0.3 or ≥0.4), and presence of lateral neck compartment nodal metastases were all associated with higher recurrence rates.
The lack of standardized definitions and terminology make the interpretation of findings difficult and limit generalizability. Future studies must focus on exploring long-term recurrence risk, in an exclusively PTC patient population, while also incorporating standardized definitions and terminology for lymph node characteristics and recurrence.