Utility of early dynamic and delayed post-diuretic 18 F-FDG PET/CT SUV max in predicting tumour grade and T-stage of urinary bladder carcinoma: results from a prospective single centre study.

OBJECTIVE: Accurate pre-treatment grading and staging of bladder cancer are vital for better therapeutic decision and prognosis. The aim of the present study was to evaluate the correlation between maximum standardized uptake value (SUVmax ) calculated during early dynamic and post-diuretic fluorine-18 fludeoxyglucose (18 F-FDG) positron emission tomography (PET)/CT studies with grade and pT-stage of bladder cancer.

METHODS: 39 patients with suspected/proven bladder carcinoma underwent 10-min early dynamic pelvic imaging and delayed post-diuretic whole-body FDG PET/CT imaging. SUVmax of the lesions derived from both studies was compared with grade and pT-stage. Relationship of SUVmax with grade and pT-stage was analyzed using independent sample t-test and analysis of variance.

RESULTS: SUVmax of the early dynamic imaging showing tumour perfusion was independent from the SUVmax of delayed imaging. High-grade tumours showed higher SUVmax than low-grade tumours in the early dynamic imaging (5.4 ± 1.4 vs 4.7 ± 1.6; p-value 0.144) with statistically significant higher value in Stage pT1 tumours (6.8 ± 0.8 vs 5.5 ± 1.2; p-value 0.04). Non-invasive pTa tumours had significantly less SUVmax than higher stage tumours during early dynamic imaging [F(4,29) = 6.860, p 0.001].

CONCLUSION: Early dynamic imaging may have a role in predicting the grade and aggressiveness of the bladder tumours and thus can help in treatment planning and prognostication. Advances in knowledge: Dynamic PET/CT is a limitedly explored imaging technique. This prospective pilot study demonstrates the utility of this modality as a potential adjunct to standard FDG PET/CT imaging in predicting the grade and aggressiveness of the bladder tumours and thus can impact the patient management.