OBJECTIVETo retrospectively analyze the long-term results of prophylactic central lymph node dissection in cN0 papillary thyroid carcinoma (PTC), and investigate the treatment method of the cervical lymph nodes for cN0 PTC.

METHODSOne hundred and thirty-six patients with cN0 PTC were treated by surgery at the Cancer Hospital of Chinese Academy of Medical Sciences from 2000 to 2006. Their clinicopathological characteristics, surgical procedures and survival outcomes were collected and analyzed.

RESULTSThe occult lymph node metastasis rate in central compartment was 61.0%. The average number of positive lymph nodes was 2.47 (1-13), in which 54 patients had 1-2 and 29 patients had ≥ 3 positive lymph nodes. Multiple logistic regression analysis showed that age less than 45 (P=0.001, OR 3.571, 95% CI 1.681-7.587)and extracapsular spread (ECS) (P=0.015, OR 2.99, 95% CI 1.241-7.202)were independent risk factors for lymph node metastasis in the central compartment. The ten-year cumulative overall survival rate was 98.3% and cumulative lateral neck metastasis rate was 25.2%. Multivariate analysis with Cox regression model showed that ECS (P=0.001, OR 5.211, 95% CI1.884-14.411) and positive lymph nodes in the central compartment ≥ 3 (P=0.009, OR 4.005, 95% CI 1.419-11.307) were independent risk factors for lymph node recurrence in the lateral neck region. The distribution of recurrent lymph nodes: level IV (82.4%), level III (64.7%), level II (29.4%) and level V (11.8%).

CONCLUSIONSRoutine central lymph node dissection, at least unilateral, should be conducted for cN0 papillary thyroid carcinoma. Attention should be paid to the treatment of lateral neck region in patients with cN0 papillary thyroid carcinoma. Selective neck dissection is suggested for cN0 PTC with ECS or positive central lymph nodes ≥ 3, or both. The range of dissection should include level III and IV at least.