Abstract 118P
Background
In advanced colorectal malignancies, multiple sites of metastasis often exist, and it is not appropriate to assume the presence of metastasis in only one location when evaluating the patient's condition since treatment decisions may be affected. Specifically, in patients with peritoneal metastasis of colorectal cancer, the application of PET/CT technology can improve diagnostic efficacy.
Methods
We studied 102 patients diagnosed with colorectal cancer with synchronous or metachronous peritoneal metastasis who underwent [18F]FAPI PET/CT and [18F]FDG PET/CT. Scores of different PET/CT peritoneal cancer indexes (PCIs), tumor-to-background ratios (TBRs), and maximum standardized uptake values (SUV max), combined with intraoperative findings and postoperative pathology, were compared to assess the differences between the two imaging techniques.
Results
Among the 102 included patients, 48 underwent surgical treatment. Total visible tumor resection, known as CC-0 cytoreduction, was achieved in 24 patients after cytoreductive surgery (CRS). In the 102 patients included, the median and range of SUV max and SUVTBR in peritoneal metastatic lesions of colorectal cancer were higher in [18F]FAPI PET/CT than in [18F]FDG PET/CT [6.2 (1.3-20.1) vs. 4.7 (0.9-26.0), P<0.01]; [4.4 (0.7-14.7) vs. 2.9 (0.4-18.0), P<0.01]. In the 48 patients who underwent surgical treatment, the preoperative PCI score from [18F]FAPI PET/CT was closer to the surgical PCI score [(864 vs. 819), P=0.25] than that from [18F]FDG PET/CT [(864 vs. 605), P<0.01]. Combined with postoperative pathology, we found that when analyzing the integral peritoneum, [18F]FAPI PET/CT had a higher sensitivity and accuracy in diagnosing peritoneal metastasis than [18F]FDG PET/CT [(72.2% vs. 53.5% P < 0.01)]; [(84.3% vs. 78.2% P=0.051].
Conclusions
The diagnostic efficacy of [18F]FAPI PET/CT for peritoneal metastasis of colorectal cancer is significantly higher than that of [18F]FDG PET/CT.
Legal entity responsible for the study
H. Wang.
Funding
H. Wang has received grants from the National Natural Science Foundation of China (grant No. 82103084 to H. Wang) and Dongguan Science and Technology of Social Development Program (grant No. 20231800904303). Z. Zhang has received grants from the National Natural Science Foundation of China (No.81901772) and the Natural Science Foundation of Guangdong Province (No.2019A1515011893, 2023A1515011300) and the State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia & The First People’s Hospital of Kashi Fund (No.SKL-HIDCA-2020-KS2). H. Wang has received grants from the Xinjiang Autonomous Region Technology Plan (grant No. 2022E02125) and The Sixth Affiliated Hospital of Sun Yat-sen University Clinical Research –‘1010’Program: 1010CG (2022)-08. K. Yang has received grants from the National Natural Science Foundation of China (Grant No. 82300619) and the Science and Technology Projects in Guangzhou (Grant No. 2023A04J2245).
Disclosure
All authors have declared no conflicts of interest.