[Related factors analysis for lymph node metastasis in papillary thyroid carcinoma: a series of 2 073 patients]

Objective: To investigate the related factors for lymph node metastasis (LNM), especially for high volume LNM (>5 metastatic lymph nodes) in papillary thyroid carcinoma (PTC). Methods: The medical records of 2 073 consecutive PTC patients who underwent lobectomy, near-total thyroidectomy or total thyroidectomy with ipsilateral or bilateral central lymph node dissection in Department of General Surgery, Peking Union Medical College Hospital from November 2013 to October 2014 were reviewed. Clinical and pathological features were collected. Univariate and multivariate analysis were performed to identify the related factors for LNM/high volume LNM. Results: In all 2 073 patients, LNM and high volume LNM were confirmed in 936 (45.15%) cases and 254 (12.25%) cases respectively. In univariate analysis, large tumor size, young patients (<40 years), male were associated with both LNM and high volume LNM. In multivariate analysis, tumor size >2.0 cm, young patients (<40 years), male were independent related factors of LNM (OR=5.262, 95% CI: 3.468 to 7.986; OR=2.447, 95% CI: 2.000 to 2.995; OR=1.988, 95% CI: 1.593 to 2.480, respectively, all P=0.000) and high volume LNM (OR=6.687, 95% CI: 4.477 to 9.986; OR=2.975, 95% CI: 2.224 to 3.980; OR=2.354, 95% CI: 1.737 to 3.191, respectively, all P=0.000). In 1 414 PTMC patients, a similar result was also demonstrated.Compared with young patients (<40 years), old patients (≥60 years) had lower incidence of LNM (25.47% vs. 52.24%, χ(2)=62.903, P=0.000) and high volume LNM (1.89% vs. 13.18%, χ(2)=37.341, P=0.000). Additionally, old patients also had lower risk of both LNM (OR=0.316, 95% CI: 0.194 to 0.517, P=0.000) and high volume LNM (OR=0.142, 95% CI: 0.034 to 0.599, P=0.000). Conclusions: The tumor size was the main related factor for both LNM and high volume LNM in PTC. The treatment should be more active in patients with tumor size >2 cm with consideration of higher incidence and risk for LNM and high volume LNM. Young patient was another important related factor for LNM and high volume LNM. In PTMC, old patients had lower incidence and risk for both LNM and high volume LNM. Dynamic observation or less surgical extent could be an option for these patients.