Cervical lymphadenectomy is frequently performed in papillary thyroid carcinoma (PTC) patients with lateral node metastasis to improve regional control, but the cervical levels that require dissection remain controversial. We conducted this study to investigate the necessity of the routine dissection of level V in papillary thyroid microcarcinoma (PTMC).

To identify the relation between PTMC and level V metastases, we analyzed 90 patients who underwent lateral neck dissection (ND). Twenty-five patients underwent lateral ND when metastasis was detected during follow-up, whereas the other 65 patients underwent total thyroidectomy with central and lateral ND at initial surgery.

There were 18 PTMC patients and 72 patients with a PTC of >1 cm. Metastasis at level III or IV was detected in 80.0% and 78.9%, respectively, whereas metastasis at level V was only detected in 12.2%, and metastasis at level II occurred in 30%. In PTMC patients, metastatic rates at levels II, III, IV, and V were 11.1%, 61.1%, 61.1%, and 5.6%, respectively, and in patients with a PTC of >1 cm, metastatic rates at levels II, III, IV, and V were 34.7%, 84.7%, 83.3% and 13.9%, respectively. PTMC was not found to be significantly associated with level V metastasis (P=0.452).

The level V metastatic rate in PTMC was no different from that of PTC>1 cm statistically. However, the metastatic rate was only 5.6% in PTMC. Therefore, we recommend that care be taken when deciding whether to perform level V dissection when dissecting the lateral cervical nodes in PTMC.