Clinical Characteristics And Prognosis Factors Of Papillary Thyroid Carcinoma Of The Isthmus

BackgroundPapillary thyroid carcinoma(PTC)is the most common thyroid tumor,accounting for about 90%of all thyroid cancers.The isthmus of the thyroid is located in front of the trachea and covered by the ribbon muscle.If PTC or the center of PTC is located in the isthmus of the thyroid,it is called papillary thyroid carcinoma of the isthmus(PTCI).The incidence of PTCI is low,accounting for about 10%of all PTC.PTCI has more aggressive features,including more extra-glandular invasion(ETE),multifocality,and lymph node metastasis.At present,surgery is the first choice for the treatment of PTC.However,due to the favorable prognosis of PTC,operation is becoming more conservative.Existing guidelines and expert recommendations for PTC are all about glandular lobe tumors,but there is lacking specific guidelines or expert advice about PTCI.There are many controversies about the treatment of PTCI,which mainly focus on the scope of surgery,whether to perform preventive central lymph node dissection.In this study,we explored the clinicopathological characteristics of PTCI,the risk factors of central lymph node metastasis(CLNM)and postoperative recurrence,and analyzed the prognosis of PTCI patients treated with different surgical methods,by analyzing the clinicopathological data of PTCI patients,in order to provide a basis for the clinical diagnosis and treatment of PTCI.ObjectiveBy analyzing the clinicopathological data of PTCI patients,to explore the clinicopathological characteristics,and the risk factors of CLNM and postoperative recurrence of PTCI.At the same time,the effect of different surgical treatment methods on the prognosis of PTIC patients was further studied.MethodsThe clinicopathological data of patients with PTCI who underwent the first operation in our hospital from June 2012 to June 2021 were collected.According to the inclusion criteria,a total of 140 patients were included.Chi-square test and multivariate Logistic regression analysis were used to analyze the risk factors of CLNM in patients with PTCI,and Log-Rank method and COX proportional hazards model were used to analyze the risk factors for postoperative recurrence in patients,and to explore the effect of different surgical methods on the prognosis of PTCI patients.ResultsA total of 140 patients were included in this study,including 31 males and 109 females.The date of the last follow-up was December 2021,follow-up time was 6-108 months,median follow-up time was 27 months.A total of 14 patients relapsed,all of which were local recurrence.The result of single-factor analysis indicates tumors with a maximum diameter of>1 cm(P=0.007),multifocal(P=0.019),ETE(P=0.029),and BRAFV600E mutation(P=0.038)showed differences in CLNM or not.The results of multivariate logistic regression analysis showed ETE(OR=2.903;95%CI:1.419-5.943;P=0.004)and BRAFV600E gene mutation(OR=2.657;95%CI:1.149-6.145;P=0.022)were independent risk factors of CLNM in PTCI patients.Log-Rank univariate analysis of PTCI patients found that ETE(P=0.016),BRAFV600E gene mutation(P=0.009),and CLNM(P=0.025)were potential risk factors for postoperative recurrence of PTCI.The result of COX multi-factor regression showed ETE(HR:5.189;95%CI:1.100-24.463;P=0.037)and BRAFV600E gene mutation(HR:2.335;95%CI:1.145-4.470;P=0.021)were independent risk factors that affecting postoperative recurrence of PTCI.The influence of the three surgical methods on the prognosis of PTCI patients was analyzed and it was found that the probability of postoperative complications in patients with total thyroidectomy and lobectomy plus isthmectomy was significantly higher than patients with isthmectomy(P<0.05).There was no significant difference in the effect of the three surgical methods on the recurrence of patients(P>0.05).Conclusions1.The incidence of CLNM and ETE in PTCI patients is high,but the overall prognosis is favorable.2.ETE and BRAFV600E gene mutation are independent risk factors of CLNM in PTCI.It is recommended to perform central lymph node dissection,when the patient have the above factors.3.ETE and BRAFV600E gene mutation are independent risk factors of postoperative recurrence in PTCI patients.4.Isthmectomy is a suitable surgical method for some PTCI patients,which could reduce postoperative complications and improve the quality of life of patients.