OBJECTIVETo discuss the pattern of central lymph node metastasis of cN0 single thyroid papillary carcinoma and provide clinical evidence-supported proof for central lymph node dissection.

METHODSThe performed thyroidectomy and bilateral central lymph node dissection for 150 patients with cN0 single papillary thyroid carcinoma. The bilateral central lymph nodes were divided into 4 parts: the cornu inferius cartilaginis thyroideae region of ipsilateral central area, the lower part of ipsilateral central area, the cornu inferius cartilaginis thyroideae region of contralateral central area, the lower part of contralateral central area on the baseline of 1 cm below the cornu inferius cartilaginis thyroideae. We analyzed the differences and influencing factors of lymph node metastasis in these 4 parts.

RESULTSThe lymph node metastasis rate in lower part of ipsilateral central area was the highest (56.7%), followed by the lower part of contralateral central area (28.0%), the cornu inferius cartilaginis thyroideae region of ipsilateral central area (17.3%), and the cornu inferius cartilaginis thyroideae region of contralateral central area (0). In the logistic analysis of multiple factors, invaded thyroid capsule was an independent factor for lymph node metastasis in both the cornu inferius cartilaginis thyroideae region of ipsilateral central area (β = 0.1835, χ(2) = 0.3102, P < 0.05) and lower part of contralateral area (β = 0.3166, χ(2) = 1.4640, P < 0.05). The patients' age ≥ 45 years (β = 0.5737, χ(2) = 6.5923) and invaded thyroid capsule (β = 0.4258, χ(2) = 3.4735) were independent factors for lower part of ipsilateral central area (both P < 0.05).

CONCLUSIONThe cornu inferius cartilaginis thyroideae region of contralateral central area of cN0 single PTC patients could not be cleared routinely.