Diagnostic Value Of ^99mTc-3PRGD₂ SPECT Imaging For Breast Cancer And Axillary Lymph Node Metastasis

Purpose:To evaluate diagnostic value of ^99mTc-3PRGD₂ SPECT imaging in breast cancer and axillary lymph node metastasis, and compared with ¹⁸F-FDG PET/CT imaging.Method:Forty-five female patients with suspected breast cancer were enrolled in this prospective study in our hospital,mean age 45.14±8.59 years（from 30 to 70 years old）,mean weight 55.02±8.28kg（from 41 to 77 kg）. Patients received a bolus intravenous injection of ^99mTc-3PRGD₂ with a dose of 11.1MBq/kg（0.3 m Ci/Kg）, the SPECT anteroposterior and lateral planar imaging and SPECT/CT tomography of chest were acquired 40 minutes later by GE Infinia Hawkeye4 SPECT, and ¹⁸F-FDG PET/CT were examined in the same period（within one week） by Siemens Biography m CT（64）. Two experienced nuclear medicine physicians analysed date of two imagings independently,mean radioactive count ratio（T/B value） of breast lesions（T） and the corresponding areas of ascending aortic blood pool（B） were calculated for semiquantitative by the SPECT, the breast lesions maximum standardized uptake value（SUVmax） and the mean standardized uptake value（SUVmean） were measured by PET/CT. Using qualitative to assess axillary lymph node metastasis. The histopathological result was considered as “gold standard”, and compared the diagnostic performance of two imagings in breast cancer and axillary lymph node metastasis. The data were analyzed by t-test, z-test, chi-square analysis（χ2 test）, ROC curve and linear regression analysis using SPSS18.0 statistical software, P<0.05 was considered statistically significant.Results:1. 42 patients were founded 45 lesions, 38 lesions were malignant and 7 lesions were benign according to histopathological result.2.No adverse reactions were observed after injection a dose of ^99mTc-3PRGD₂.There was a significant difference in T/B ratio of ^99mTc-3PRGD₂ and SUVmax of¹⁸F-FDG between malignant lesions and benign lesions（ 4.47±1.82 vs. 2.43±1.02, t=2.86, P < 0.01;8.45±3.57 vs. 3.12±1.13, t=7.4, P < 0.01）.3. ROC analyses were performed to determine the optimal cut-off values of two imaging for the detection of malignant breast cancer. The sensitivity, specificity and accuracy of ^99mTc-3PRGD₂ SPECT and ¹⁸F-FDG PET/CT were 86.8%、85.7%、86.7%（cutoff = 2.75 of T/B） and 92.1%、85.7%、91.1%（cutoff = 3.3 of SUVmax）,respectively, p > 0.05. According to the ROC analysis, the area under the curve for¹⁸F-FDG PET/CT（area = 0.946） was higher than that for ^99mTc-3PRGD₂ SPECT（area =0.839）, but there was no statistical difference（Z=0.88, P > 0.05）.4. There was a linear relationship between T/B ratio of ^99mTc-3PRGD₂ and SUVmean of ¹⁸F-FDG for all breast lesions（r = 0.654; P <0.01）.5. Diagnosis of axillary lymph node metastasis, the sensitivity, specificity,accuracy, positive predictive value and negative predictive value of ^99mTc-3PRGD₂ SPECT and ¹⁸F-FDG PET/CT were 78.05%, 99.5%, 95.8%, 96.97%, 95.6% and85.37%, 98.98%, 96.64%, 94.59%, 97.01%, respectively. There was no statistical difference between ^99mTc-3PRGD₂ SPECT and ¹⁸F-FDG PET/CT（p > 0.05）.6. 9 patients with distant metastases were diagnosised in two imagings. Compared with ¹⁸F-FDG PET/CT, some lumbar spine metastases, pelvis metastases, liver metastases were not detected in ^99mTc-3PRGD₂ SPECT.Conclusion:1. ^99mTc-3PRGD₂ is a safe, non-invasive, inexpensive new SPECT imaging agent.2. ^99mTc-3PRGD₂ and ¹⁸F-FDG uptake of malignant breast lesions was significantly higher than benign lesions. The diagnostic efficiency of breast cancer was no statistical difference between ^99mTc-3PRGD₂ SPECT and ¹⁸F-FDG PET/CT. And tracer uptake of99mTc-3PRGD2 and ¹⁸F-FDG was correlated for breast lesions.2. The ^99mTc-3PRGD₂ SPECT imaging showed lower sensitivity than ¹⁸F-FDG PET/CT for detection of axillary lymph node metastasis by visual analysis, whereas the statistical difference was not significant.3. Two imagings was no difference in breast cancer staging, but ^99mTc-3PRGD₂ SPECT finding metastases in lumbar spine, pelvis, liver, etc. was not good as ¹⁸F-FDG PET / CT.4. In conclusion, ^99mTc-3PRGD₂ SPECT imaging showed good diagnostic performance in breast cancer, axillary lymph node metastasis and distant metastasis.