[⁶⁸Ga]Ga-FAPI-46 PET accuracy for cancer imaging with histopathology validation: a single-centre, single-arm,...

Area of Science:

• Oncology
• Radiochemistry
• Nuclear Medicine

Background:

• Fibroblast activation protein α (FAP) plays a role in cancer progression.
• [68Ga]Ga-FAPI-46 is a novel radiotracer for Positron Emission Tomography-Computed Tomography (PET-CT) imaging.
• Previous studies suggested promising diagnostic accuracy for [68Ga]Ga-FAPI-46 in cancer staging.

Purpose of the Study:

• To determine the positive predictive value (PPV) of [68Ga]Ga-FAPI-46 PET for identifying FAP-expressing tumors.
• To explore the correlation between the intensity of radiotracer uptake on PET scans and immunohistochemical FAP expression levels.
• To evaluate the safety and potential of [68Ga]Ga-FAPI-46 as an imaging biomarker.

Main Methods:

• A single-center, phase 2 interventional trial involving adult patients with various confirmed or suspected cancer types undergoing staging or restaging.
• Patients received an intravenous injection of [68Ga]Ga-FAPI-46, followed by PET-CT imaging.
• Histopathological confirmation and immunohistochemical analysis of FAP expression were used as reference standards. Three independent readers analyzed PET-CT images.

Main Results:

• The patient-based PPV of [68Ga]Ga-FAPI-46 PET for detecting FAP-positive tumors was 90% (95% CI 84-95), and the region-based PPV was 92% (85-96).
• Adverse events possibly related to [68Ga]Ga-FAPI-46 were reported in 6% of participants, with no serious adverse events attributed to the tracer.
• The study enrolled 155 participants, with a median age of 62 years.

Conclusions:

• [68Ga]Ga-FAPI-46 PET is a safe and effective imaging biomarker for detecting FAP-expressing tumors.
• The high PPV supports its potential utility in clinical cancer diagnostics.
• Further research is recommended to refine specificity and establish its role in routine clinical practice.