Recruiting

18F-FDG Versus 68Ga-FAPI-46 as PET Tracer in ER-positive Breast Cancer.

ClinicalTrials.gov IDNCT06335069

PhasePHASE2

Enrollment20

SponsorMaastricht University Medical Center

Age18 Years

SexFEMALE

I'm interested View official listing

Conditions studied

Breast Cancer, Breast Neoplasms, Breast Diseases

About this study

The extent of breast cancer is an important prognostic factor in patients diagnosed with this disease. Therefore, adequate staging at diagnosis is a requisite for optimal treatment. In all patients diagnosed with locally advanced breast cancer (LABC), distant staging using 18F-FDG PET/CT is recommended. However, the degree of metabolic uptake in the primary breast tumor is significantly lower in the ER+ subtype compared to HER2+ and triple negative breast cancer (TNBC). As a consequence, a suboptimal 18F-FDG uptake in ER+ breast cancer patients can potentially lead to missed distant metastases. Fibroblast-activating protein inhibitor (FAPI) is a recently developed radiotracer that binds to FAP, a stromal antigen overexpressed in more than 90% of epithelial-derived tumors and their metastases. Previous studies all show 68Ga-FAPI PET/CT to have a higher detection rate compared to 18F-FDG PET/CT. However, all previous studies were performed without considering breast cancer subtype. If the metabolic uptake by 68Ga-FAPI-46 is higher in ER+ breast cancer patients, more lesions will be detected, resulting in a more appropriate treatment for these patients. Therefore, in this pilot study, the investigators aim to compare the diagnostic performance of 18F-FDG with 68Ga-FAPI-46 as PET-tracer in ER+ breast cancer patients.

Interventions

Diagnostic Test: 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI — All participating patients will undergo an additional 68Ga-FAPI- 46 PET/CT and 68Ga-FAPI-46 PET/MRI scan prior to their breast cancer treatment.

Primary outcomes

To determine essential input parameters for an adequate sample size calculation for a diagnostic study that compares the diagnostic accuracy of 18F-FDG and 68Ga-FAPI-46 as PET tracer in patients with ER+ breast cancer. (Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.)

Eligibility information

Inclusion Criteria: * Female patient with histopathologically proven ER+ breast cancer. * Diagnosed with locally advanced (primary tumor \>5 cm and/or presence of axillary lymph node metastases) or recurrent breast cancer, or metastatic breast cancer for which 18F-FDG PET/CT or 18F-FDG PET/MRI staging is performed. * Willing and able to undergo the study procedures. * Has personally provided written informed consent. Exclusion Criteria: * Age \<18 * Pregnancy * Patients with secondary malignancies (except non-melanoma skin cancer) * No 18F-FDG PET/CT or 18F-FDG PET/MRI scan. * Contra-indications for PET/MRI such as pacemaker, aneurysm clips, metallic device in their body, severe claustrophobia, and severe obesity * Chronic inflammatory disease such as rheumatoid arthritis. * Patients with severe hepatic or renal impairment (eGFR ≤45mL/min/1.73m²) * Inability to provide informed consent.

Study locations

Maastricht University Medical Center+, Maastricht, 5800 Netherlands

Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.

Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-09-30.