Macrometastasis in Papillary Thyroid Cancer Patients is Associated with Higher Recurrence in Lateral Neck Nodes

Background The use of routine central compartment neck dissection surgery for papillary thyroid carcinoma (PTC) is controversial. Although macroscopic central neck lymph node metastasis (CNLN) in PTC is a poor prognostic factor correlated with increased loco-regional recurrence, the significance of microscopic metastasis to the central lymph nodes is not established. Herein, we aimed to assess the influence of the size of CNLN on disease recurrence among PTC patients. Methods Data from 233 patients who underwent less than total thyroidectomy with CNLN dissection in 1989-1999 were retrospectively reviewed. The patients were assigned to three groups according to the central node metastasis: no metastasis (Group I), micrometastasis (< 2 mm, Group II), and macrometastasis (>= 2 mm, Group III). Clinicopathological features, recurrence rate, site of recurrence, and disease-free survival (DFS) were assessed. Results Of the 233 patients enrolled (mean follow-up period, 16.1 years), 134 (57.5%) had no central neck metastasis, 37 (15.9%) had micrometastasis, and 62 (26.6%) had macrometastasis. Demographics and tumour variables were similar among the three groups. Recurrence rates were 12.7, 16.2, and 43.5% in Groups I, II, and III, respectively (p < 0.001). Group III had a 3.2-fold increased relative risk of recurrence and a significantly decreased DFS compared to Group I. Group III showed significantly higher rates of lateral neck nodes metastasis than Groups I and II. Conclusions In conclusion, macrometastasis significantly affects disease recurrence in PTC patients, whereas microscopic metastasis has only marginal effects. Macroscopic CNLN metastasis showed a significantly higher recurrence in the lateral neck node compared to micrometastasis.