A prognostic predicting model integrating preoperative 18F-FDG PET/CT metabolic parameter and clinicopathological biomarkers for patients with ccRCC

Background: Accurate risk stratification is critical for the management of patients with clear cell renal cell carcinoma (ccRCC). This study aims to explore the predictive value of preoperative ¹⁸ F-FDG PET/CT metabolic parameter combined with clinicopathological features for postoperative disease-free survival (DFS) in ccRCC patients. Methods: Newly diagnosed ccRCC patients who underwent ¹⁸ F-FDG PET/CT prior to surgery were retrospectively reviewed. Maximum standardized uptake value (SUVmax) was acquired from the preoperative ¹⁸ F-FDG PET/CT. Clinicopathological features, including the tumor node metastasis (TNM) stage, body mass index (BMI), hemoglobin (Hb), World Health Organization (WHO)/the International Society of Urological Pathology (ISUP) grade, primary tumor size, carbonic anhydrase IX (CAIX), tumor-infiltrating lymphocytes (TILs), etc., were also obtained. Cox proportional hazards analyses were executed to identify prognostic factors for DFS. The predictive efficacy of the model was assessed by the area under the curve (AUC). Glycolysis genes in ccRCC were analyzed using the TCGA database. Results : 59 ccRCC patients were included and 26 (44.1%) cases developed disease progression. On univariate analysis, BMI (≤ 25.45 kg/m2), Hb (≤ 130 g/L), clinical symptoms, TNM stage (III/ IV), SUVmax (> 4.20), primary tumor size (> 5.75 cm), WHO/ISUP grade (G3/4), CAIX expression (1+), and high TILs were significant prognostic factors of inferior DFS ( P < 0.05). On multivariate analysis, SUVmax ( P =0.026, HR=4.248; 95%CI: 1.184-15.239), BMI ( P =0.002; HR=0.233; 95%CI: 0.094-0.580), and WHO/ISUP grade ( P =0.005, HR=5.888; 95%CI: 1.689-20.524) still maintained independency in prognosis prediction. The prognostic model composed of the above three independent predictors achieved excellent predictive efficacy by virtue of a C-index of 0.89, with AUC values of 0.922, 0.919, and 0.899 at 1-, 3-, and 5-year, respectively. Moreover, the glycolysis-related genes of GCKR and GCK were obviously upregulated in the disease-progression group. Conclusion: ccRCC patients with low preoperative BMI, elevated SUVmax, and high WHO/ISUP grade are more likely to develop disease progression after operation. Implementing closer surveillance or aggressive early intervention for these patients is recommended to optimize prognosis.