FDG-PET/CT vs. CT for Monitoring Metastatic Breast Cancer

Several studies have shown improved sensitivity of FDG-PET/CT compared with conventional imaging for diagnosing metastatic breast cancer in retrospective and smaller prospective studies. For response monitoring, we expect FDG-PET/CT to detect disease progression earlier than CT in patients treated for metastatic breast cancer, enabling earlier start of second-line therapies. Current knowledge about the potential benefit of FDG-PET/CT for response monitoring of patients with metastatic breast cancer comes from observational studies. Consequently, current evidence is only hypothesis-generating and prospective, randomized trials such as the MONITOR-RCT are needed to corroborate these findings. The MONITOR-RCT clinical trial aims to investigate whether monitoring with FDG-PET/CT can improve survival in patients diagnosed with metastatic breast cancer. It is a parallel group comparative randomized trial comparing an experimental monitoring strategy based on FDG-PET/CT with a standard monitoring strategy based on CT. Participating patients should have newly diagnosed metastatic breast cancer and be considered eligible for initiating first-line medical treatment and subsequent regular response monitoring. A total of 420 patients will be included in the study, with recruitment taking place across 11 participating hospital sites in Denmark, Germany, and Italy. The main questions it aims to answer are: * Can monitoring with FDG-PET/CT compared to conventional CT prolong the overall survival of MBC patients? * Is this-as expected-due to earlier detection of disease progression and earlier initiation of second-line therapies? * Is this accompanied by less need for additional diagnostics, less need for hospitalization, and improved quality of life? Participants will: * Undergo FDG-PET/CT scans at scheduled intervals to monitor disease progression. * Be given standard treatments as part of oncological care, which is informed by the FDG-PET/CT scans * Fill out questionnaires about their quality of life at various time points throughout the study. Objectives are: Primary: To demonstrate superiority in overall survival of response monitoring with FDG-PET/CT in patients with metastatic breast cancer over response monitoring based on CT. Appropriately adapted PERCIST criteria for FDG-PET/CT and the RECIST1.1 criteria for CT will be used. Secondary: To demonstrate superiority in quality of life and exposure to oncologic treatment with FDG-PET/CT and to investigate the cost-effectiveness.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Women and men aged ≥18 years
2. Diagnosis of distant relapsed MBC (biopsy-verified) or de novo breast cancer. In patients with distant relapsed MBC, biopsy verification from a distant metastasis is required. In patients with de novo MBC, biopsy verification of primary tumor and diagnostic imaging with distant metastasis with a typical pattern of MBC is required.
3. Considered eligible for first-line systemic treatment
4. Considered eligible for continuous treatment monitoring by scans.
5. Signed informed consent
6. Participants must have the ability to read and understand the following languages based on their country of participation: in Denmark, patients must be able to read and understand Danish; in Italy, they must be able to read and understand Italian or English; and in Germany, they must be able to read and understand German or English.

In case of patients for whom it is necessary to start first-line systemic treatment while still waiting for the evaluation of the biopsy, it is allowed to include the patients, as long as the other criteria are fulfilled and the biopsy is made or planned. In case verification by biopsy fails, the patients will leave the trial (cf. 4c). We expect that up to 3% of the patients included will start first-line systemic treatment prior to evaluation of the biopsy

Exclusion Criteria:

1. Pregnant or lactating women
2. Ongoing oncological treatment for another cancer
3. Exclusively brain metastasis
4. Allergy to FDG

• BACKGROUNDNaghavi-Behzad M, Vogsen M, Vester RM, Olsen MMB, Oltmann H, Braad PE, Asmussen JT, Gerke O, Vach W, Kidholm K, Kodahl AR, Weber W, Hildebrandt MG. Response monitoring in metastatic breast cancer: a comparison of survival times between FDG-PET/CT and CE-CT. Br J Cancer. 2022 May;126(9):1271-1279. doi: 10.1038/s41416-021-01654-w. Epub 2022 Jan 10. PMID 35013575
• BACKGROUNDVogsen M, Harbo F, Jakobsen NM, Nissen HJ, Dahlsgaard-Wallenius SE, Gerke O, Jensen JD, Asmussen JT, Jylling AMB, Braad PE, Vach W, Ewertz M, Hildebrandt MG. Response Monitoring in Metastatic Breast Cancer: A Prospective Study Comparing 18F-FDG PET/CT with Conventional CT. J Nucl Med. 2023 Mar;64(3):355-361. doi: 10.2967/jnumed.121.263358. Epub 2022 Oct 7. PMID 36207136