New Meta-Analysis Assesses Impact of 68Ga-FAPI PET CT/MRI for Ovarian Cancer

While computed tomography (CT), magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) are more commonly utilized for the detection of ovarian cancer, emerging research suggests that ⁶⁸Ga-fibroblast activation protein inhibitor (FAPI) PET/CT may be a viable imaging alternative.

For a new meta-analysis, recently published in Academic Radiology, researchers reviewed data from five studies, published between 2023 to 2024, that examined the use of ⁶⁸Ga-FAPI PET in 206 patients with ovarian cancer.

The study authors found that ⁶⁸Ga-FAPI PET CT/MR had a 90 percent pooled sensitivity rate and a 95 percent pooled specificity rate for ovarian cancer.

Additionally, the researchers pointed out that the PET agent demonstrated 94 percent sensitivity and 95 percent specificity for metastatic lymph nodes.

“Compared to ¹⁸F-FDG, 68Ga-FAPI offers several advantages, such as lower uptake in normal organs (except skeletal muscle), increased uptake of the tracer in metastatic lesions and decreased background activity,” wrote lead study author Lixin Sun, M.D., who is affiliated with the Department of Nuclear Medicine at Beijing Luhe Hospital and Capital Medical University in Beijing, China, and colleagues.

While cautioning about the possibility of false negatives with ⁶⁸Ga-FAPI PET CT/MRI due to small lesions and abdominal movement, the meta-analysis authors found the use of ⁶⁸Ga-FAPI PET CT/MRI exhibited 93 percent sensitivity and 96 percent specificity for peritoneal carcinomatosis.

Emphasizing research that has shown a buildup of ⁶⁸Ga-FAPI in PET imaging of malignancies that may have low uptake of FDG, the meta-analysis authors suggest that more targeted use of ⁶⁸Ga-FAPI may bolster the agent’s detection of smaller lesions.

“It is expected that stroma-targeted PET will have a higher innate sensitivity compared to glycolysis-targeted PET to identify tiny lesions since FAPI targets the tumor stroma. Furthermore, ⁶⁸Ga-FAPI exhibits extremely low intestine physiologic uptake, resulting in strong target-to-background contrast and distinct detection of tiny peritoneal foci,” pointed out Sun and colleagues,” pointed out Sun and colleagues.

(Editor’s note: For related content, see “SNMMI: New Study Suggests Merits of FAPI PET/CT for Breast Cancer Staging,” “Consensus Recommendations on MRI, CT and PET/CT for Ovarian and Colorectal Cancer Peritoneal Metastases” and “Multicenter Study Shows Merits of AI-Powered Ultrasound Assessment for Detecting Ovarian Cancer.”)

In regard to limitations of the meta-analysis, the authors conceded that all the review studies were completed in China, possibly limiting extrapolation of the meta-analysis findings to broader populations. They also noted limited research to assess the impact of ⁶⁸Ga-FAPI PET CT/MR in initial staging and restaging for ovarian cancer.