Visualization of metabolic parameters after colorectal carcinoma patients using [68Ga]Ga-FAPI PET

Abstract

Background This study evaluated the relationship between metabolic parameters derived from gallium 68-labeled fibroblast-activation protein inhibitor ([68Ga]Ga-FAPI)and Tumor, Node, Metastasis stages in colorectal carcinoma. Methods A retrospective analysis was conducted on patients with colorectal carcinoma who underwent pre-surgical [68Ga]Ga-FAPI positron emission tomography/computed tomography between October 2021 and June 2022. The metabolic parameters derived from [68Ga]Ga-FAPI positron emission tomography/computed tomography for primary colorectal carcinoma lesions were calculated and recorded at different thresholds, including the maximum and mean standardized uptake values, as were the gross tumor volume- and total lesion-fibroblast-activation protein inhibitor. Tumor, Node, Metastasis classification was defined according to the 7th American Joint Committee on Cancer. The difference in quantitative parameters between Tumor, Node, Metastasis stage groups was assessed, and receiver operating characteristic analyses with the area under the curve were performed to evaluate the predictive performance of metabolic parameters. Results Thirty-three patients (median age, 61 years [interquartile range, 54–71 years]; 19 men, 14 women) were evaluated. With respect to [68Ga]Ga-FAPI parameters, 30% of maximum standardized uptake values, 40% of maximum standardized uptake values, 50% of maximum standardized uptake values, 60% of maximum standardized uptake values, 30% of mean standardized uptake values, 40% of mean standardized uptake values, and 50% of mean standardized uptake values were correlated with T3–4 stage primary colorectal carcinoma (all p < 0.05). Among these parameters, 30% of mean standardized uptake values showed the highest predictive performance for T3–4 stages, with an area under the curve of 0.761 (95% confidence interval: 0.591–0.931), sensitivity of 67.4% (95% confidence interval: 0.472–0.681), and specificity of 90.0% (95% confidence interval: 0.557–0.796). Conclusions Metabolic parameters derived from [68Ga]Ga-FAPI provide a noninvasive assessment of Tumor status in patients with colorectal carcinoma, and 30% of mean standardized uptake values has the highest predictive value for Tumor stage diagnosis.