The Added-value of Staging 18F-FDG PET/CT in the Prediction of Overall Survival in the Patients with Bladder Cancer.

Objectives: This retrospective study aimed to evaluate the prognostic importance of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-positive pelvic lymph nodes (LNs) and extra-pelvic disease on staging ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) in patients with bladder cancer.

Methods: Bladder cancer patients who underwent staging ¹⁸F-FDG PET/CT were included in the study. Histopathologic features of tumors, therapy histories, presence of distinguishable tumors on CT and PET images, sizes and maximum standardized uptake value (SUV_max) of primary tumors, total numbers, sizes, and SUV_max of ¹⁸F-FDG-positive pelvic and extra-pelvic LNs, and total numbers and SUV_max of distant metastases (M1a/1b) were recorded. Patients were followed up until death or the last medical visit. Factors predicting overall survival were determined using Cox regression analysis.

Results: Fifty-five patients [median age: 70 (53-84), 48 (87.3%) male, 7 (12.7%) female] with bladder cancer were included in this study. Twenty-nine (52.7%) patients had ¹⁸F-FDG positive pelvic LNs, while 24 (43.7%) patients had ¹⁸F-FDG positive extra-pelvic disease. Patients with ¹⁸F-FDGpositive pelvic LNs had a higher rate of extra-pelvic disease (p=0.003). The median follow-up duration was 13.5 months. The median overall survival was 16.3 months [95% confidence interval (CI) 8.9-23.7]. The primary tumor distinguishability on PET (p=0.011) and CT (p=0.009) images, the presence of ¹⁸F-FDG-positive pelvic LNs (p<0.001) and ¹⁸F-FDG-positive extra-pelvic disease/distant metastases (M1a/M1b) (p<0.001), and the number of distant metastases (p=0.034) were associated with mortality. The ¹⁸F-FDG-positive extra-pelvic disease/distant metastases [p=0.029, odds ratio: 4.15 (95% CI 1.16-14.86)] was found to be an independent predictor of mortality in patients with bladder cancer.

Conclusion: The presence of ¹⁸F-FDG-positive extra-pelvic disease in pretreatment ¹⁸F-FDG PET/CT is an important prognostic factor in bladder cancer patients.