68Ga-FAPI-04 PET/CT in Selected Breast Cancer Patients With Low FDG Affinity

Abstract

PurposeIn this prospective study, PET findings of 18F-FDG PET/CT in breast cancer staging were compared with 68Ga–FAP inhibitor (FAPI) 04 PET/CT findings in selected cases with relatively low 18F-FDG uptake in the primary tumor or with suspected nodal or distant metastases.Patients and MethodsTwenty-four women with a median age of 45 years (range, 36–67 years) who underwent initial staging 18F-FDG PET/CT for breast cancer underwent 68Ga-FAPI-04 PET/CT imaging within the same week. SUVmax and quantities of primary tumors and locoregional and distant metastatic lesions were recorded from both images, and these data were compared statistically.ResultsThe histological subtypes of primary tumors were 11 invasive lobular, 8 invasive ductal, and 5 mucinous subtypes. More intense 68Ga-FAPI-04 uptake (mean, 17.1 ± 7.9; 7.4–38.5) was detected in all primary tumoral lesions compared with 18F-FDG (mean, 6.3 ± 3.9; 1.5–20.5) (P = <0.001, Z = 4.107). Additional lesions showing 68Ga-FAPI-04 uptake in the breast were detected in 29.2% (n = 7) of patients. In 8.3% (n = 2) of the patients, the primary lesion showed only 68Ga-FAPI-04 uptake. In 68Ga-FAPI-04 PET/CT, 25% (n = 6) of the patients showed more lymph node involvement and more intense uptake in the ipsilateral axilla. In addition, infraclavicular (level 3) lymph nodes in 4 patients (16.7%), supraclavicular lymph nodes in 1 patient, and internal mammary lymph nodes in 1 patient were detected only on 68Ga-FAPI-04 PET/CT. In a patient with lung and bone metastases, 68Ga-FAPI-04 uptake was higher, and the lung nodule showed only 68Ga-FAPI-04 uptake.ConclusionsIn selected low-FDG-affinity breast cancer patients, 68Ga-FAPI-04 PET/CT showed the primary tumor with higher sensitivity and higher SUVmax values compared with 18F-FDG PET/CT. In addition, it is believed that this method may contribute to the management of patients' treatment by increasing the nodal stage.

Combination of 68Ga-FAPI-04 and Dedicated Breast PET (MAMMI PET) Outperformed Breast MRI and 18F-FDG PET/CT by Revealing Nipple and Skin Involvement of Breast Cancer

“…2 Recently, 68 Ga-FAPI-04 PET/CT was published as an alternative PET radiotracer with promising results in the detection of breast cancer, especially for low FDG-avid tumor types. 3,4 Beyond that, 68 Ga-FAPI-04 integrated PET/MRI showed high diagnostic accuracy in breast cancer with the advantage of hybrid imaging. 5 MRI has high negative predictive value for nipple-areola invasion; however, disconcordance between MRI and pathologic findings can be seen in especially high-risk group.…”

“…18 F-FDG PET/CT has limited role in assessment of T stage in breast cancer, 1 particularly in lobular carcinoma and luminal A type tumors, which show low FDG affinity 2 . Recently, 68 Ga-FAPI-04 PET/CT was published as an alternative PET radiotracer with promising results in the detection of breast cancer, especially for low FDG-avid tumor types 3,4 . Beyond that, 68 Ga-FAPI-04 integrated PET/MRI showed high diagnostic accuracy in breast cancer with the advantage of hybrid imaging 5 .…”