| Background and objectiveDifferentiated thyroid cancer(DTC)is the fastest growing malignancy in Guangdong Province,China.And the papillary thyroid cancer(PTC)is the most common type of DTC.So far the prognostic value of lymph node metastases(LNM)in DTC remains controversial,the indications and extent of lymph node dissection,postoperative therapy and follow-up plans for patients remains unclear.MethodsA multicenter retrospective study was conducted in patients with DTC from July 1997 to July 2015 in 4 medical centers of Guangdong Province.Data including demographics,clinicopathologic and ultrasonographic data from the patients were collected and analyzed.The disease-free survival(DFS)and overall survival were calculated and the clinicopathologic predictors of LNM and prognosis in patients were analyzed.Results(1)With regard to DTC patients,LNM group had lower 5-year DFS(69.16%,11 months)and shorter median time of recurrence than those in non-LNM group(87.96%,8.5 months,respectively,P<0.001).Higher incidence of temporary unilateral vocal cord palsy,permanent hypoparathyroidism,permanent unilateral vocal cord palsy,and bilateral vocal cord palsy in LNM group were observed.Both univariate and multivariate analyses in LNM group revealed that age,pathological tumor node metastasis(pTNM)stage,and histology were related to DFS(P<0.05).(2)The further analysis of PTC revealed that recurrence was significantly higher in patients with LNM than in patients without LNM(P<0.05).LNM in PTC also primarily influenced DFS.Age<45 years,larger tumor(>5 mm)and multifocality were predictors of LNM;age<45 years,larger tumor size and absence of concomitant Hashimoto’s thyroiditis were associated with central LNM;male sex,extrathyroidal extension and multifocality were correlated with lateral LNM(P<0.05).There was no difference in postoperative recurrence between patients with central LNM or lateral LNM(P>0.05).Age>45 years and male sex were risk factors of recurrence in PTC patients with LNM.Male patients with central LNM and older patients with lateral LNM exhibited worse prognosis(P<0.05).(3)In addition,the analysis of lateral LNM in clinically node negative(cNO)patients with PTC shows that presenting with Hashimoto’s thyroiditis,extrathyroidal extension,multifocal lesions,calcification by ultrasound and central LNM were independent predictors of lateral LNM(P<0.05).The risk score was defined as follows:risk score=1.2×(if Hashimoto’s thyroiditis presents)+1.5×(if extrathyroidal extension presents)+1.5×(if multifocal lesions presents)+ 2.0×(if calcification presents)+ 1.5×(if central LNM presents).The scoring system based on these predictors was statistically significant(P<0.001)with an area under the ROC curve of 0.847,with an index point ≥1.35 favoring lateral LNM,which had a sensitivity of 78.3%and a specificity of 87.6%.ConclusionLNM have significant prognostic value in patients with DTC in Guangdong,China and primarily influence DFS.Prophylactic lymph node dissection is recommended in PTC patients who have high risks of LNM from Guangdong,China.More aggressive postoperative treatment and more frequent follow-up could be considered for PTC patients with risk factors influencing prognosis.Besides,our scoring system for predicting lateral LNM in cN0 patients with PTC can be helpful for optimizing the surgical extent when common preoperative evaluations are inadequate. |
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