Evaluation of renal cell carcinoma histological subtype and fuhrman grade using 18 F-fluorodeoxyglucose-positron emission tomography/computed tomography.

OBJECTIVES: We evaluated 18 F-fluorodeoxyglucose (FDG) uptake by renal cell carcinomas (RCCs) to determine whether different histological subtypes and Fuhrman grades can be distinguished.

METHODS: We retrospectively reviewed the records and maximum standardised uptake value (SUVmax) of 147 patients with 154 RCCs who underwent FDG-positron emission tomography (PET)/computed tomography (CT) prior to tumour resection.

RESULTS: The SUVmax was significantly lower in chromophobe RCC (chRCC) tumours than in clear cell RCC (ccRCC; p = 0.003) and papillary RCC (pRCC; p = 0.034) tumours. The mean tumour SUVmax was 4.58 ± 4.1 (range, 1.29-30.4) for ccRCC, 3.98 ± 1.9 (range, 0.49-6.72) for pRCC, and 1.93 ± 0.9 (range, 0.89-3.41) for chRCC. The SUVmax was not significantly different between the ccRCC and pRCC groups. In ccRCC and pRCC tumours, high-grade tumours had a significantly greater SUVmax (p < 0.001 and p < 0.05) than low-grade tumours by analysis of variance (ANOVA) and the Mann-Whitney U test. In ccRCC, multivariate regression analysis indicated that the SUVmax was a significant indicator of Fuhrman grade. No significant differences in uptake were observed between high- and low-grade chRCC tumours.

CONCLUSIONS: The SUVmax obtained using FDG-PET/CT may be an important indicator for predicting tumour grade in ccRCC and pRCC.

KEY POINTS: • FDG accumulation reflects tumour aggressiveness and correlates with Fuhrman grade. • FDG-PET/CT enables the differentiation of high- and low-grade ccRCC and pRCCs. • FDG-PET/CT may valuable in the identification of some high-grade RCCs.