The Characteristics Of Central Metastatic Lymph Node In Low-risk Ptmc Patients

Background and objectiveBecause of the popularity of health examination and The application of high resolution type-B ultrasonic.The incidence of papillary thyroid carcinoma(PTC)increased rapidly in recent decades.Many researchers suggest that some low-risk papillary thyroid microcarcinoma(PTMC)patients can be under active observation instead of have surgery immediately.But there is still a lot of controversy in the world.The focus of the debate is that about 30?40%low-risk patients diagnosed by ultrasound preoperatively was proved to have central lymph node metastasis by postoperative pathological examination.Recently,many researchers found that those PTMC patients who didn't have prophylactic elective central compartment dissection(CCND),their logoreginal recurrence rate was lower than 10%.he purpose of these article is to study the metastatic lymph nodes' characters of low-risk papillary microcarcinoma,and classify the metastasis in metastatic lymph node.Thereupon then study if the observation of low-risk PTMC is reasonable.Materials and methodAccording to the definition of low risk thyroid papillary carcinoma based on Kuma hospital in Japan.467patients who have low-risk thyroid papillary microcarcinoma underwent thyroidectomy with Prophylactic lymph node excision in Department of Head and Neck Surgery of Zhejiang University,Sir Run Run Shaw Hospital,School of Medicine from January 2014 to December 2015.We observed their pathological section after surgery.Observed and mearsured by using microscope.Observed and analyzed the central metastasis lymph nodes' number,excisional lymph nodes' number,size of metastasis and lymph node,major diameter of metastasis.And divided them into three groups,no metastasis,micrometastasis(the number of metastasis lymph nodes<5 and the maximum diameter<2mm)and macrometastasis.Results:In 467 patients,women 373(79.9),men 94(20.1%),average age is 44.1.The postoperative pathology found the average tumor size is 0.58cm,138(29.6%)patients have central lymph node metastasis,55(11.8%)have extrathyroid extension,190(40.7%)patients have more than one original tumor,7(1.5%)patients have intrathyroid spreading,123(26.3)patients have Hashimoto diease.Among 138 patients who have central lymph node metastasis,106(76.8%)patients are low risk papillary thyroid carcinomas.Conclusion:Lymph node metastasis is related with male,age,multifocal,disseminates in the gland,so it's important to consider these risk factors to decide whether patients needs prophylactic central compartment neck dissection or not.And we found when the size of tumor is smaller than 8mm,94.7%patients don't have lymph node metastasis or only have micrometastasis,can be active observed instead of surgery.