Clinical Value Of The FT₄/FT₃ Quotient Combined With TSH In Predicting Differentiated Thyroid Carcinoma

Objective: Thyroid cancer by histological classification is divided into differentiated and undifferentiated thyroid cancer.Differentiation of thyroid cancer is not obvious early symptoms and clinical symptoms are not strong,leading to early diagnosis is very difficult,seriously affecting the patient’s treatment.At present,the tumor markers with high specificity and sensitivity for the diagnosis of thyroid cancer have not been found at home and abroad.This study mainly investigates the ratio of free thyroxine(FT4)to free triiodothyronine(FT3),free thyroxine(FT4),free triiodothyronine(FT3),thyroid stimulating hormone(TSH),age and The relationship between gender and other six indicators and differentiated thyroid cancer(DTC)is to provide a quick and simple and affordable detection method for early detection,early screening and early diagnosis of DTC.Methods:Select thyroid disease patients who were treated by surgery in the Hospital from January 2016 to December 2017,and select 218 cases with complete clinical data.According to pathological findings after operation,differentiated thyroid cancer is displayed.122 Cases(malignant group),96 cases of benign thyroid nodules(benign group).All patients’ age,sex,serum FT3,FT4,TSH,and the ratio of FT4/FT3 were all entered into the database.SPSS 19.0 software was used to process the data,which was in accordance with the normal distribution measurement data and was expressed as ±s.The t-test was used for comparison.The non-normal distribution measurement data was expressed as the median and the interquartile range,that is,M(Q1,Q3)was expressed and compared.Mann-Whitney U rank sum test was used;count data were compared using χ2 test.P<0.05 was considered statistically significant.Univariate analysis and multi-factor unconditional logistic regression models were used to screen out the corresponding risk factors.The receiver operating characteristic(ROC)curve was plotted,and the area under the curve(AUC)was calculated to perform comparative analysis and joint diagnosis of each index,and the best cut-off value was obtained.The Results:1.There was no significant difference in the sex composition and free thyroxine(FT4)between malignant and benign groups(P>0.05).2.Univariate analysis showed that the mean age and free triiodothyronine(FT3)in malignant group were significantly lower than those in benign group [(44.48±12.07)years old vs(52.81±12.99)years old and(4.31±0.61)pmol/L vs(4.73±1.05)pmol/L],the difference was statistically significant(P<0.01);the prevalence rates of malignant group and benign group were significantly different among different age groups(X2=22.67,P<0.01).).FT4/FT3 and thyroid stimulating hormone(TSH)were significantly higher than the benign group [3.65±0.66 vs 3.34±0.89 and 2.15(1.43.27)m U/L vs 1.63(1.05,2.19)m U/L],and the difference was statistically significant.(P<0.01).3.The multi-factor non-conditional logistic regression analysis results showed that in the multi-factor logistic regression model of FT3,although its P<0.05,the partial regression coefficient(B value)is negative(FT3:B=—0.748),which is not considered dangerous factors;FT4/FT3,TSH,and age stratified multivariate logistic regression model established,and the differences were statistically significant(FT4/FT3: OR =1.631,95% CI,1.079 to 2.465,P = 0.02;TSH: OR = 1.722,95% CI 1.251 to 2.369,P= 0.001;Age: 30-55 years,OR = 6.347,95% CI.2.087 to 19.302,P = 0.001,Age: 55 years or older,OR = 3.167,95% CI.1.650 to 6.079,P = 0.001).4.According to the area under the ROC curve(AUC),the AUC for FT4/FT3,TSH,FT4/FT3 combined with TSH and FT4/FT3 combined with TSH and age was 0.626(95% CI 0.551 to 0.702,P = 0.001),0.662(95% CI 0.591 to 0.734,P = 0.000),0.698(95% CI 0.629 to 0.767,P = 0.000)and 0.748(95% CI 0.684 to 0.811,P = 0.000).5.The best cut-off values of FT4/FT3 and TSH were 3.345 and 2.055 m U/L,respectively,with sensitivity of 65.7% and 57.4% and specificity of 60.4% and 71.8%,respectively.The sensitivity and specificity of FT4/FT3 combined with TSH(FT4/FT3+TSH)were 85.5% and 42%,respectively.The sensitivity and specificity of FT4/FT3 combined with TSH and age(FT4/FT3+TSH+age)were 77.1 and 77.1,respectively.%,60.4%.One of the single indicators of FT4/FT3 and TSH was used to diagnose differentiated thyroid cancer.The sensitivity was not high.If FT4/FT3,TSH,and age were combined to diagnose DTC,the diagnostic sensitivity of DTC was greatly improved,reaching 77.1%,and the specificity was not low.Conclusion:1.FT4/FT3,TSH and age are risk factors for differentiated thyroid cancer(DTC).2.The combined diagnosis of FT4/FT3,TSH,and age was significantly more effective than single diagnosis of differentiated thyroid cancer.3.When FT4/FT3>3.345 and/or TSH>2.055 uIU/ml,the accuracy of the joint prediction of DTC is significantly increased.4.The combined detection of FT4/FT3,TSH,and age may temporarily replace serum tumor markers as the primary standard for a standardized differentiated thyroid cancer diagnosis system before serum marker markers with high sensitivity and specificity for differentiated thyroid cancer come out.Diagnosis can be used as a screening indicator for high-risk thyroid nodules and healthy people.Clinical observation and monitoring of changes in both indicators have a certain preventive effect in social life and have great application value.