The Impact On Central Lymph Node Metastasis In Patients Suffered From Papillary Thyroid Carcinoma Concomitant With Hashimoto’s Thyroiditis

Objective:To evaluate the impact of papillary thyroid carcinoma concomitant with Hashimoto’s thyroiditis on central lymph node metastasis.Methods:We retrospectively reviewed102patients with papillary thyroid carcinoma treated in the department of general surgery of Qilu Hospital during2010-2011.39cases substantiated Hashimoto’s thyroiditis by postoperative histopathologic examination were classified into Hashimoto’s thyroditis group, meanwhile other69cases were categorized to the control group. All patients had undergone lobectomy of the affected thyroid lobe plus subtotal resection of the contralateral lobe plus ipsilateral central lymph node dissection, some cases contained isthmectomy. Total thyroidectomy plus bilateral central lymph node dissection were operated on patients with bilateral thyroid carcinoma. Patients with diagnosed or highly suspected lateral lymph node metastasis had undergone functional dissection of lateral lymph node additionally. The two groups and total sample were compared in terms of tumor diameter, preoperative TSH concentration, age and multifocality.Results:The prevalence of central lymph node metastasis in Hashimoto’s thyroiditis group was significantly lower than control group (35.9%vs.57.1%, p=0.037); while there was no notable difference concerning the number of metastatic central lymph nodes between the two group. Tumor diameter (1.0cm), preoperative TSH concentration (2.5μIU/ml), age (45year) and the presence of multifocality were used to compare the two groups and the total sample separately. Striking difference was observed between the two groups in the comparison of tumor diameter>1.0cm or preoperative TSH concentration>2.5μIU/ml (p=0.047and p=0.046respectively). Meanwhile, tumor diameter, preoperative TSH concentration, age and multifocality were used as influence factors to analyze the total sample separately, the incidence of central lymph node metastasis in patients with maximal tumor diameter>1cm was significantly higher than those with maximal tumor diameter≤1cm (59.0%vs.34.1%, p=0.014); the incidence of lymph node metastasis in patients with solitary tumor was significantly lower than patients with multi foci tumor (40.3%vs.70.0%, p=0.006). Multivariate Logistic regression was applied to analyze predictive factors of central lymph node metastasis, after adjusting for Hashimoto’s thyroiditis, tumor diameter, preoperative TSH concentration, age and multifocality, a negative association was noted on central lymph node metastasis with the coexistence of Hashimoto’s thyroiditis(OR=0.390, CI=0.157-0.971, p=0.043), and the coexistence of Hashimoto’s thyroiditis can be viewed as a protective factor in this study.Conclusions:There was a negative relevance between central lymph node metastasis in papillary thyroid carcinoma and the coexistence of Hashimoto’s thyroiditis, the concomitance of Hashimoto’s thyroiditis can be viewed as an independent negative predictive factor for central lymph node metastasis in patients with papillary thyroid carcinoma. No evidence supported that the number of metastatic lymph nodes between the two groups had a remarkable difference in this study.