High rate of IIA/IIB neck groups involvement supports complete lateral neck dissection in thyroid carcinoma

Background: Although therapeutic lateral neck dissection (LND) may be indicated in thyroid carcinoma, the cervical lymph node groups IIA and IIB, according to Robbins classification, are often not removed. The aim of our study was to determine the relevance of complete comprehensive LND in thyroid carcinoma.

Methods: We conducted a retrospective study between January 2011 and August 2018 in a university teaching hospital. Histopathological analysis of LND performed during total thyroidectomy in thyroid carcinoma was reviewed according to lymph node level. To demonstrate that neck dissection of upper groups, IIA/IIB, is necessary when therapeutic LND is indicated in thyroid carcinoma, we compared histopathological involvement in complete comprehensive LND of the upper groups IIA/IIB to the lower groups III/IV/V.

Results: A total of 30 LND (24 patients) were suitable for analysis. Analysis by neck side revealed that comprehensive LND dissection samples were negative in 3 cases, and positive in 27. In those 27 positive LND, 15 demonstrated involvement of the groups IIA/IIB, and 12 were positive for involvement of the III/IV/V groups only. The combined presence of positive IIA/IIB and positive III/IV/V was observed in 15 of the 27 neck sides. There was no positive IIA/IIB without positive involvement of III/IV/V groups.

Conclusions: The high rate of positive cervical lymph nodes in the upper groups IIA/IIB supports complete comprehensive LND rather than selective III/IV/V LND in thyroid carcinoma surgery. However, impact on survival and whether postoperative radioactive iodine treatment may be modulated remain to be studied.