Emerging research demonstrates that whole-body (68Ga)Ga-FAPI-04 PET/CT (FAPI PET) offers enhanced detection of peritoneal carcinomatosis in comparison to abdominopelvic contrast-enhanced CT (ceCT) in women with ovarian cancer.
For the prospective study, recently published in the Journal of Nuclear Medicine, researchers reviewed ceCT and FAPI PET data for 200 women (mean age of 56.4) with primary epithelial ovarian carcinoma. In addition to quantification of peritoneal carcinomatosis with the Peritoneal Cancer Index (PCI), the study authors compared the imaging modalities to intraoperative assessment.
How Does FAPI PET Compare to CECT for Detecting Peritoneal Carcinomatosis in Women with Ovarian Cancer?
The researchers found that FAPI PET provided a higher mean PCI in comparison to ceCT (14.14 vs. 10.8).
Overall, FAPI PET offered over 27 percent higher sensitivity (81.8 percent vs. 54.6 percent), lower specificity (89.3 percent vs. 96.4 percent) and higher accuracy (86 percent vs. 78 percent) than ceCT for detection of peritoneal carcinomatosis in this patient population, according to the study authors.
“Unlike 18F-FDG PET, which reflects glucose metabolism and is limited by bowel activity, FAPI PET results in rapid uptake, high tumor-to-background contrast, and minimal physiologic noise, making it particularly useful for detecting (peritoneal carcinomatosis),” noted lead study author Somashekhar SP, MD, who is affiliated with the Department of Surgical Oncology at the Aster International Institute of Oncology in Bangalore, India, and colleagues.
Three Key Takeaways
• FAPI PET outperforms ceCT for detecting peritoneal carcinomatosis overall. In this 200-patient study, FAPI PET showed substantially higher sensitivity (81.8 percent vs. 54.6 percent) and accuracy (86 percent vs. 78 percent) than ceCT, along with a higher mean PCI (14.14 vs. 10.8), though ceCT retained slightly better specificity (96.4 percent vs. 89.3 percent).
• The sensitivity advantage is most pronounced in surgically critical regions. FAPI PET showed markedly higher sensitivity than ceCT in the upper abdomen (76.5 percent vs. 23.5 percent) and small bowel with mesentery (50 percent vs. 31.3 percent) — areas that directly affect whether complete cytoreductive surgery is feasible — while sensitivity was comparable to ceCT in the pelvis and central abdomen.
• Improved detection in these regions may carry greater prognostic and surgical planning value than the global PCI score alone. The small bowel/mesentery and hepatoduodenal ligament are key determinants of surgical resectability. These findings suggest that FAPI PET could better inform preoperative decision-making in ovarian cancer.
Where FAPI PET Has Significantly Higher Sensitivity than ceCT for Peritoneal Carcinomatosis
While FAPI PET and ceCT provided comparable sensitivity in the pelvis and central abdomen, the study authors noted that FAPI PET provided 53 percent higher sensitivity for peritoneal carcinomatosis in the upper abdomen (76.5 percent vs. 23.5 percent) and over 18 percent higher sensitivity in the small bowel (50 percent vs. 31.3 percent).
“Our findings indicate the superiority of FAPI PET in terms of sensitivity, regional detection rates, and overall accuracy, particularly in surgically challenging regions comprising the small bowel with mesentery (regions 9–12) and the hepatoduodenal ligament (region 2). These regions are known to influence the feasibility of complete (cytoreductive surgery) and may therefore have greater prognostic relevance compared with the global PCI,” pointed out SP and colleagues.
Final Notes
(Editor’s note: For related content, see “What a Meta-Analysis Reveals About FAPI PET/CT for Detection of Peritoneal Metastases,” “Can FAPI PET Enhance Pre-Op Evaluation of Peritoneal Carcinomatosis?” and “New Meta-Analysis Assesses Impact of 68Ga-FAPI PET CT/MRI for Ovarian Cancer.”)
Beyond the inherent limitations of a single center study, the study authors conceded the lack of correlation between surgical PCI and pathology results, the lack of comparison between FAPI PET and 18F-FDG PET/CT, and the possible confounding effect of neoadjuvant chemotherapy on FAPI PET imaging.
