Incidence and Clinical Impact in Papillary Thyroid Microcarcinoma With Lateral Cervical Node Metastasis

Abstract BackgroundsLateral lymph node metastasis (LNM), which significantly impacts papillary thyroid carcinoma (PTC) patients’ prognosis. Papillary thyroid microcarcinoma (PTMC) is known to have a much better prognosis than non-PTMC, but it has not been known whether there is such a difference even with lateral LNM. MethodsThis retrospective study included a series of 3336 consecutive PTC patients who underwent thyroidectomy. Of them, 206 had lateral LNM and were divided into the PTMC and non-PTMC groups by tumor size (1-cm) for comparing the prevalence of prognostic factors. ResultsLNM was in 157/1131 (13.9%) non-PTMC patients and 49/2205 (2.2%) PTMC patients. Eleven of the 206 (5.3%) lateral LNM cases not found on US were only seen on computed tomography. The prevalence of prognostic factors which include an age of >55 years, >5 metastatic lymph nodes (LNs), high metastatic-to-examined LN ratio, and large metastatic LNs (>3 cm) were not significantly different between PTMC and non-PTMC group. ConclusionIn PTC with lateral LNM, the prognosis is likely to be similar regardless of tumor size. Considering the modest risk of lateral LNM in PTMC, FNA for small thyroid tumor and radiologic tests for lateral LNM should be encouraged.