According to a study published in The Journal of Nuclear Medicine, a new class of radiopharmaceuticals was tested in a small group of patients who had over 30 types of cancer. The radiotracer is used with a PET/CT scan (positron emission tomography/computed tomography) to image a variety of tumors with high image contrast, and researchers are studying its possible uses in cancer diagnosis and treatment planning, including for patients receiving cancer immunotherapies. No role for this tracer in gene therapies or applications in functional medicine has been reported. The Ga-FAPI radiotracer works by targeting fibroblasts that are associated with various types of cancers and typically contribute to a large portion of a tumor’s mass. Cancer-associated fibroblasts differ from normal fibroblasts because they express high levels of FAP proteins (fibroblast activation protein). Fibroblast activation protein inhibitors (FAPI) labeled with the radioactive isotope gallium-68 (68Ga-FAPI) are used in PET imaging research, and FAP-targeted treatments, including some that use NK cells, are being studied in early research and clinical trials.
Researchers from the Society of Nuclear Medicine and Molecular Imaging (SNMMI) used modified PET/CT scanners to evaluate 80 patients with 31 different types of cancer to determine whether they could distinguish between metastatic, primary & recurring cancers. However, the test results showed that the difference between metastatic lesions and primary tumors was not statistically significant.
In this study, the Ga-FAPI radiotracer showed the highest uptake in the following types of cancers:
- Esophageal
- Cholangiocarcinoma
- Lung cancer
- Breast cancer
- Sarcoma
In this study, the Ga-FAPI radiotracer showed intermediate uptake in the following cancers:
- Head-neck cancer
- Colorectal cancer
- Hepatocellular cancer
- Prostate cancer
- Pancreatic cancer
- Ovarian cancer
In this study, the Ga-FAPI radiotracer showed the lowest uptake in:
- Adenoid cystic cancers
- Pheochromocytoma cancer
- Gastric cancers
- Renal cell cancer
- Differentiated thyroid cancers
The potential benefits of Ga-FAPI radiotracers also include the avoidance of fasting or requiring a specific position during scans.
The researchers also noted possible improvements in patient comfort and clinical workflow compared with current PET tracers, which may also interest clinicians working in regenerative medicine.