Clinical analysis of secondary cervical lymph node dissection in papillary thyroid carcinoma

Objective To investigate the value of secondary cervical lymph node dissection in papillary thyroid carcinoma (PTC). Methods PTC patients with recurrence re-operated in a previously dissected area at our hospital during 2000-2016 were included in this analysis. Patients were divided according to the operative interval of 6 months. The level and number of lymph node metastasis and the number of lymph node dissection were analyzed to calculate the ratio of lymph node metastasis. Results A total of 336 PTC patients received 360 side lateral cervical lymph nodes dissection. The ratio of recurrence in unilateral lateral neck is 92.9%(312/336). The ratio of recurrence in multiple levels (more than two regions) were 47.5% (171/360). The recurrence ratio of level Ⅱ, Ⅲ, Ⅳ and Ⅴ were 55.6%(200/360), 44.2%(159/360), 59.7%(215/360) and 10.3%(37/360), respectively. Lymph node metastases were inclined to level Ⅱ (33.6%) and Ⅳ (35.8%). The mean number of lymph node dissection and metastasis in the group of operative interval ≤ 6 months was 26.56 per case and 4.37 per case, respectively. The mean number of lymph node dissection and metastasis in the group of operative interval >6 months was 16.80 per case and 3.20 per case, respectively. The number of lymph node dissection and metastasis between these two groups were significantly different (P=0.001, P<0.001). Conclusions Lymph node metastasis of PTC patients with secondary cervical lymph node dissection are inclined to level Ⅱ and level Ⅳ. Moreover, multi-level metastasis is not rare. Level Ⅱ and level Ⅳ require more attention in the first operation. Most of the patients undergo reoperation because of residual lymph nodes from the previous treatment. Normalization and completeness of the initial dissection are particularly important to PTC patients. Key words: Thyroid neoplasms; Neck dissection; Tumor recurrence