Researchers compare the diagnostic accuracy of Ga-FAP-2286 and 18F-FDG in nuclear medicine cancer imaging

A new radiotracer, Ga-FAP-2286, has reportedly been found to be more effective than the most commonly used nuclear medicine cancer imaging radiotracer, 18F-FDG. In a study published in the March issue of The Journal of Nuclear Medicine, Ga-FAP-2286 detected 100% of primary tumors across multiple cancer types as compared to 18F-FDG, which identified only 80%. 68Ga-FAP-2286 was also more effective in detecting lymph node metastases and distant metastases.

Currently, 18F-FDG, which measures glucose metabolism, is used extensively in nuclear medicine cancer imaging, according to the researchers. Recent advances have shown that fibroblast activation protein (FAP), which is over expressed in cancer cells, may be a better target for the imaging of solid tumors.

Figure 1. Maximum-intensity projection images of 18F-fluorodeoxyglucose (FDG), 68Ga-FAP-2286, and 68Ga-FAPI-46 PET/CT imaging in seven patients with different types of cancer (histologically confirmed). Tumor lesions are indicated with arrows. Abbreviation: Ca = carcinoma, HNCUP = head and neck carcinoma of unknown primary, NPC = nasopharyngeal carcinoma.

“In this study we aimed to investigate the diagnostic accuracy of 68Ga-FAP-2286—a radionuclide developed to target FAP—for detecting the primary and metastatic lesions in patients with various types of cancer”, shared Haojun Chen, MD, PhD, nuclear medicine physician at the First Affiliated Hospital of Xiamen University in Xiamen, China.

Reportedly, 64 patients with 14 types of cancer were included in the study; 63 of the patients underwent paired 68Ga-FAP-2286 and 18F-FDG PET/CT; 19 patients underwent paired 68Ga-FAP-2286 and 68Ga-FAP-46 (another 68Ga-radiolabeled variant). Results were evaluated and compared.

Researchers shared that  68Ga-FAP-2286 PET yielded a higher radiotracer uptake, tumor-to-background ratio and tumor detectability than 18F-FDG. In addition, 68Ga-FAP-2286 and 68Ga-FAPI-46 yielded comparable clinical results.

“The novel radionuclide 68Ga-FAP-2286 is shown to be a promising FAP-inhibitor derivative for safe cancer diagnosis, staging and restaging”, stated Chen. “Specifically, it may be a better alternative for diagnosing the cancer types that exhibit low-to-moderate uptake of 18F-FDG, such as head and neck, gastric, pancreatic and liver cancer”. Chen also noted that FAP-2286 not only exhibits promising characteristics for diagnosis, but also for cancer treatment. “Due to its molecular makeup, FAP-2286 can be paired with 177Lu to create a new radiopharmaceutical therapy. 177Lu-FAP 2286 has the potential to offer potent and selective FAP binding, which could lead substantial therapeutic efficacy for cancer patients in the future,” Chen concluded.