| Background and objectiveThe incidence of thyroid cancer has increased in the past few decades.Differentiated thyroid cancers(DTCs),encompassing papillary thyroid carcinoma(PTC)and follicular thyroid carcinoma(FTC),are the most prevalent histological types.Although they have a rapid growth of incidence,they still have a stable number of deaths,which make thyroid cancer present some special epidemiological features different from any other tumors.The incidence of papillary thyroid microcarcinoma(PTMC)has also increased largely as a result of the rapid increase in the availability of newer sensitive diagnostic tools.The management of thyroid cancer has changed to be variable along with a rapid improvement of detection rate.It provides doctors more choices for making therapeutic decisions,on the other hand,it remains a challenge for clinicians to identify malignant TNs from benign nodules.Therefore,we aimed to analyze the epidemiological and pathological features of thyroid cancer,and to explore their changes during the past 10 years.We also aimed to identify clinical,biochemical and ultrasonographic predictors for malignant thyroid nodules(TNs)in patients with confirmed pathological diagnosis and to develop a predictive scoring model for malignancy in TNs.MethodsWe reviewed the medical records of patients who had undergone surgery for TNs(n=10447)at Qilu Hospital of Shandong University between January 2005 and April 2016.The final diagnosis was considered only by histopathologic diagnosis of surgical specimens.Descriptive statistics were used and categorical variables were compared by chi-square test.Multivariate logistic regression was performed to determine independent risk factors,and a predictive scoring model was created based on the predictive probability of the regression equation.The score cut-off values were calibrated using receiver operating characteristic(ROC)curve analysis.A p-value of<0.05 was considered statistically significant.Results1.During these more than 11 years,the number of patients who had undergone surgery for TNs was increasing from 220 in 2005 to 2031 in 2015,this represented almost a 9.2-fold increase.The number of thyroid cancers was also increasing,from 48 in 2005 to 1320 in 2015 by 27.5-fold.At the same time,the proportion of thyroid cancers in TNs had risen from 21.8%in 2005 to 69.3%in 2016(P<0.01).But there still were 22.0%patients had unnecessary surgeries.2.The final pathology data showed malignancy in 5450 patients(52.2%),of which the most common presented type was differentiated carcinoma(5271 patients),including 5031(92.3%)papillary and 211(3.9%)follicular carcinomas.Other malignant carcinoma including 87(1.6%)medullary carcinomas,29(0.5%)poorly differentiated carcinomas,27(0.5%)lymphomas,30(0.6%)metastatic carcinomas,35(0.6%)undifferentiated and other rare carcinomas.3.The proportion of PTC in TCs increased from 85.4%in 2005 to 85.4%in 2016.The proportion of lymph nodes metastasis decreased from 33.3%in 2005 to 28.9%in 2016.4.PTMC increased from 9 in 2005 to 446 in 2015.The proportion of PTMC inTC was highest to 49.6%in 2014.5.The number of patients who had undergone surgery for TNs and TC in male and female groups both increased from 2005 to 2016,and the sexual ratio both were almost steady at about 1:3.5.The malignant rate of TNs was much the same in male and female groups(52.3%versus 52.2%,P=0.999).6.Of all the 1767 PTMC,543 were complicated with nodular goiter,238 were complicated with Hashimoto disease,and 208 were complicated with lymph nodes metastasis.7.40 PTC had immunohistochemistry results,of which CK19 was expressed in 26 patients,Galectin-3 was expressed in 23 patients and the positive rate of Ki67 was<5%.11 PTC had lymph nodes metastasis,of which CK19 was expressed in 6 patients,Galectin-3 was expressed in 4 patients.41 MTC had immunohistochemistry results,of which TG was negative expressed in 39 patients,CgA was expressed in 37 patients,Syn was expressed in 36 patients,CT was expressed in 22 patients,CEA was expressed in 19 patients,and the positive rate of Ki67 was<10%.13 MTC had lymph nodes metastasis,of which TG was negative expressed in 12 patients,CgA was expressed in 11 patients,Syn was expressed in 10 patients,CT was expressed in 7 patients.8.2312 patients had surgery with small TNs(?1cm)because malignancy was indicated by US,of which 1767 were comfirmed to be thyroid cancer.So the specificity of US was 76.4%(1767/2312).US features including hypoechogenicity,irregular shapes,poorly defined margins and abnormal lymph nodes were related to malignancy(P<0.01).9.Significant increases in the prevalence of malignancy were detected in patients at both extremes of age(<40 yr or?80 yr)(P<0.001,OR 1.98,95%CI 1.81-2.16).10.The proportion of follicular cancers in the group of patients who lived on the coast was lower than in those who lived inland(0.8%versus 4.4%;p<0.01),while the proportion of papillary cancers in the patients who lived on the coast was higher than in those who lived inland(96.4%versus 91.5%;P<0.01).11.Independent predictors of malignancy were extremes of age(<40 years or?80 years),duration of disease<2 yrs,family history of thyroid cancer,history of breast diseases,TSH?1.25?IU/ml,nodule size<2 cm,macro calcifications,microcalcifications,solid composition,hypoechogenicity,irregular shapes,poorly defined margins,increased intranodular vascularity,taller-than-wide shapes,and abnormal lymph nodes.12.A predictive scoring model demonstrated an AUC of 0.88(95%CI 0.53-0.62)at a cut-off point of 10 scores.Conclusion1.The accuracy of preoperative diagnosis has increased.But there still were many patients had unnecessary operations.2.The most common presented type of TCs was PTC,which was increasing while the lymph nodes metastasis was decreasing in these years.The increasing of TCs due much to the increasing of PTC.3.The malignant rate of TNs in male and female was almost the same.4.Iodine intake might influence the pathological type of thyroid cancer.5.PTMC could not be considered as early stages of PTC.6.Immunohistochemistry results of TCs might not associated with lymph nodes metastasis but histopathologic types.7.The study verified predictors of malignant TNs.8.A predictive scoring model was found to be a useful tool in diagnostic work-up of TNs. |
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