Pattern and related factors of lateral cervical lymph node metastasis in patients with cN0 papillary thyroid carcinoma

Objective To evaluate the pattern of lateral cervical metastases and to investigate the risk factors for lateral cervical lymph node metastases in paoiuary thyroid carcinoma patients with clinical negative lateral neck lymph node.Methods 73 patients with paoiuary thyroid carcinoma who underwent prophylactic lateral neck dissections(level Ⅱ-Ⅵ or level Ⅱ-ⅣandⅥ) were reviewed retrospectively on their medical records paoiuary thyroid carcinoma.None of patients in this study had a clinically positive lymph node.Neck dissection specimens were obtained for histological analysis for node metastasis with respect to the individual neck levels.Results Occult metastases in lateral neck were observed in 12(16.4 ％)patients.9.6 ％,0,13.6 ％,9.6 ％,0,4.8 ％ and 42.4 ％ patients had histologically positive lymph nodes in levels Ⅱa,Ⅱb,Ⅲ,Ⅳ,Va,Vband Ⅵ respectively.In multivariate analysis,lymphatic metastases in level Ⅵ was associated with lateral neck metastasis(OR=7.3,P=0.020)in cN0 patients with paoiuary thyroid carcinoma.Conclusion Levels Ⅲ,Ⅱa and Ⅳwere the most common stages showing occult lymph node metastases.Prophylactic lateral neck dissections may be omitted in the treatment of cN0 PTC patients ff level Ⅵ lymphatic metastases are not found on histological exam. Key words: Thyroid neoplasms; Carcinoma,papillary; Lymphatic metastasis; Neck dissection