Use of Whole-Body MRI in Metastatic Breast Cancer

Take-Away Points

• ■ Major Focus: To assess the impact of whole-body (WB) MRI added to routine CT, bone scintigraphy, and fluorodeoxyglucose (FDG) PET/CT imaging on systemic anticancer treatment decisions in patients with metastatic breast cancer.

• ■ Key Results: WB MRI identified additional sites of metastatic disease compared with CT, bone scintigraphy, and fluorine 18 (¹⁸F) FDG PET/CT in nearly 33% of patients. Discordant findings were found between WB MRI and CT or FDG PET/CT in nearly 20% of patients assessed for treatment response.

• ■ Impact: Use of WB MRI may provide better assessment of disease extent and progression in patients with metastatic breast cancer.

WB MRI is a promising modality to assess metastatic bone disease and may have applications in breast cancer, where routine imaging with CT, bone scintigraphy, or FDG PET/CT may fail to recognize the true extent or progression of metastatic disease during treatment.

Bhaludin et al conducted a retrospective analysis of 105 patients with known metastatic breast cancer who underwent WB MRI and CT, bone scintigraphy, or FDG PET/CT within 8 weeks of WB MRI. WB MRI identified additional sites of metastatic disease, mostly involving the liver and bones, not observed at routine imaging in 33.8% of patients. WB MRI also identified disease progression before CT and/or bone scintigraphy in patients being assessed for treatment response. Discordant findings between WB MRI and CT or FDG PET/CT occurred in 19.4% of these patients. A total of 71% of altered treatment decisions resulted from progressive disease identified only at WB MRI. WB MRI identified more sites of additional metastatic disease in patients with invasive lobular carcinoma, which can be challenging to detect at conventional imaging due to its infiltrative nature and low FDG uptake, resulting in a greater number of treatment changes (46.4%) than in patients with invasive ductal carcinoma (10.8%). The authors noted limitations of a retrospective cohort study where imaging was not conducted contemporaneously.

Large randomized studies are needed to investigate potential benefit of WB MRI as a primary diagnostic tool in invasive lobular carcinoma, as well as impact of WB MRI on patient outcomes.

Highlighted Article

• Bhaludin B, Tunariu N, Senthivel N, et al. Does the addition of whole-body MRI to routine imaging influence real-world treatment decisions in metastatic breast cancer? Cancer Imaging 2022;22:26. doi: https://doi.org/10.1186/s40644-022-00464-4