[18F]FDG whole-body PET-MR including an integrated breast MR protocol for locoregional and distant staging in breast cancer patients-a feasibility study

Purpose To investigate in a feasibility study the combination of [F-18]FDG whole-body (WB) positron emission tomography-magnetic resonance (PET-MR), including an integrated breast MR within a single protocol for locoregional and distant staging in breast cancer patients. Methods Consecutive patients with breast cancer diagnoses according to conventional imaging modalities (full-field digital mammography (FFDM) and ultrasound (US)) were prospectively included. All patients underwent [F-18]FDG WB PET-MR, including an integrated dedicated breast MR (prone position) and WB PET-MR (supine position) protocol. Results of [F-18]FDG WB PET-MR, including integrated breast MR, versus conventional imaging modalities were compared. Results From April 2021-April 2022, 28 patients were included. On conventional imaging, cT1-2 breast cancer was present in 22 (FFDM) and 23 (US) out of 28 patients. With regard to clinical nodal status, eight patients were considered cN0, eighteen cN1 (1-3 suspicious lymph nodes), and two patients were cN2 (four suspicious axillary lymph nodes/internal mammary lymph node metastasis). [F-18]FDG WB PET-MR, including an integrated breast MR protocol, upstaged clinical tumor status in two patients and clinical nodal status in nine patients according to both [F-18]FDG WB PET-MR and breast MR findings. In addition, distant metastases were detected in three patients (liver/bone), and another patient was diagnosed with a synchronous primary tumor (lung cancer). Conclusion [F-18]FDG WB PET-MR, including an integrated breast MR within a single protocol in breast cancer patients, is feasible and provides a promising new approach in breast cancer patients with regard to locoregional and distant staging. Critical relevance statement [F-18]FDG whole-body PET-MR, including an integrated breast MR protocol, is feasible and allows locoregional and distant staging within a single imaging exam in breast cancer patients.