Evaluation Of The Diagnostic Ability Of ¹⁸F-FDG PET/CT Imaging For Breast Masses And Its Correlation With Molecular Subtypes Of Breast Cancer

Objective:This study evaluated the diagnostic efficacy of ¹⁸F-FDG PET/CT imaging in primary breast cancer and compared it with ultrasound imaging.In addition,this study evaluated the association between the uptake of FDG in primary breast cancer and its molecular subtypes.Methods:A total of 696 patients with breast masses were included in this study.Inclusion criteria:1)all patients were clinically diagnosed as breast masses;2)US examination was performed before PET/CT;3)Surgical resection or puncture was performed on all lesions to obtain pathological results;4)The intervals of PET/CT,US and surgical resection or puncture were all within one week.Exclusion criteria:1)breast surgery,chemotherapy or radiotherapy history;2)other malignant tumors within 5 years;3)pregnant and lactating women.Ultrasound examination:the position,size,aspect ratio,shape,internal echo and calcification of the breast mass were observed,and they were classified into 1-5 categories according to the BI-RADS scoring standard.PET/CT examination:Before examination,the patient should be fasting for at least 6 hours,stop insulin for at least 6 hours,and the blood glucose level should be less than 10 mmol/L.Intravenous injection of ¹⁸F-FDG（dose:333-481m Bq）was followed by quiet rest for45-60 minutes.The scanning area was from the head to the mid-thigh.After the lesions were identified and the ROI was drawn,the SUVmax value was calculated.Pathological images were obtained by HE staining,and pathology was used as the"gold standard"to determine the nature of breast masses.Immunohistochemical staining of breast samples was performed for molecular typing of breast masses.According to the hormone receptor status of ER,PR and HER2 and the expression level of proliferation marker Ki-67,malignant tumors were divided into four molecular subtypes:Luminal A,Luminal B,HER-2 and triple negative.Using ROC curve analysis to determine the cut-off value of SUVmax,and USES the c² test or Mc Nemar test for ultrasonic and PET/CT in the diagnosis of performance comparison.The correlation between SUVmax and molecular subtypes was analyzed by t-test,Welch test or Mann-Whitney U test.P<0.05 was statistically significant.Statistical software SPSS 26.0 statistical software was used.Results:This study included 696 cases of lesions（benign lesions in 203 cases,493 cases of breast cancer）,in patients with breast cancer,when the cut-off a value of 3.76,the sensitivity and negative predictive value of ultrasonic diagnosis of breast neoplasm were significantly higher than that of PET/CT（P<0.05）,specificity,positive predictive value was significantly lower than that of PET/CT（P<0.05）,no accuracy in statistical difference（P>0.05）.In 4b patients,when PET/CT SUVmax cut-off value was 4.45,the corresponding sensitivity,specificity,accuracy,positive predictive value and negative predictive value of diagnosis were 87.9%,97.3%,91.3%,98.3%and 81.8%,respectively.In this study,the SUVmax value of ER negative group was higher than that of ER positive group（P<0.05）.SUVmax value in PR negative group was higher than that in PR positive group（P<0.05）.The value of SUVmax in HER2-positive group was higher than that in HER2-negative group（P<0.05）.The SUVmax value of Ki-67high expression group was higher than that of Ki-67 low expression group（P<0.05）.92 patients（19.0%）had Luminal A,267 patients（55.0%）had Luminal B,58 patients（12.0%）had HER 2,and 68 patients（14.0%）had triple negative.The SUVmax value of Luminal A subtype with the lowest ¹⁸F-FDG intake was lower than that of Luminal B subtype,HER-2 subtype and triple negative subtype,and the difference was statistically significant（P<0.05）,but there was no statistically significant difference among the latter three groups（P>0.05）.Conclusion:¹⁸F-FDG PET/CT has a high diagnostic ability for primary breast cancer,especially in patients with breast masses with ultrasound score of class 4b.SUVmax value of primary breast cancer was correlated with Luminal A subtype.