MRI Apparent Diffusion Coefficient Values In Evaluating The Prognosis Of Breast Cancer Patients

Objective:To analyze the correlation between the apparent diffusion coeffcient（ADC）of magnetic resonance imaging（MRI）and the risk factors of recurrence and disease-free survival（DFS）in invasive ductal carcinoma（IDC）patients,and to explore the prediction of ADC value on the prognosis of patients with invasive ductal carcinoma.Methods:The mean ADC values measured by diffusion weighted imaging（DWI）in 147 patients with IDC diagnosed by pathology after surgery were analyzed retrospectively.The differences of ADC values in different subgroups were analyzed by t test and non-parametric rank sum test.ROC curve determined the value of ADC value in differentiating relapsed and non-relapsed events,and divided the ADC value into groups A and B according to the cut-off value.Group A（60 cases）:ADC>0.907 x 10^-3mm²/s,and group B（87 cases）:ADC value≤0.907 x 10^-3mm²/s.Logrank test analyzed the difference of DFS between the two groups and performed stratified analysis.Chi-square test and bivariate correlation analysis verified the correlation between ADC values and patients’age,histological grade（G）,TNM stage,ER,PR,HER2,Ki67,EGFR and other clinicopathological factors.Univariate and multivariate COX model analysis validated the independence of ADC values in evaluating patients’prognosis.Results:There was a significant difference in the ADC value between the recurrent group and the non-recurrent group(0.832x10^-3mm²/s vs 0.920x10^-3mm²/s,p=0.0001).The median ADC value of patients<35 years old was lower than that of patients≥35 years old（p=0.029）.The ADC distribution of tumor size was significantly different（p=0.040）.The median ADC value of T2 tumor was lower than that of T3 and T1.There were significant differences in ADC values among different stages（p=0.003）.The median ADC value of stage II tumors was lower than that of stage I and III.The median ADC value(0.884x10^-3mm²/s)of ER positive patients was lower than that of ER negative patients(0.937x10^-3mm²/s),and the average ADC value of triple negative and HER2overexpression patients was higher than that of Luminal B1.ROC curve showed that ADC=0.907 x 10^-3mm²/s（≤0.907 with risk of recurrence and metastasis）was the cut-off value,and the sensitivity and specificity were 86.84%and50.46%,respectively.The Logrank test showed A significant difference in prognosis between group A and group B（P<0.05）.The risk of recurrence and metastasis was 5.5 times higher in group B than in group A,with shorter DFS（57.7 m vs 70.3 m）.The multivariate COX regression model showed that ADC≤0.907 x 10^-3mm²/s was an independent factor in predicting patients’recurrence and metastasis,and was not affected by other relevant factors.For every 1.0 x 10^-3mm²/s decrease in ADC values,the DFS events in that population increased by 99.3%（HR:0.007;95%CI:0.001-0.071;p=0.00003）.Conclusion:1.ADC value may have certain reference value in predicting recurrence and metastasis of breast cancer,the risk of recurrence and metastasis of breast cancer is negatively correlated with ADC value,ADC≤0.907x10^-3mm²/s indicates a higher risk of recurrence and shorter DFS.2.ADC value is related to age,histological grade,tumor subtype,TNM stage and ER status,but not to lymph node status,PR,HER2 and Ki67.