Incidental uptake of 18F-fluorodeoxyglucose in the prostate gland

Summary Aim: To perform a systematic review and meta-analysis of published data on the prevalence and risk of malignancy of pros- tatic incidental uptake (PIU) detected by flu- orine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) or PET/computed tomography (PET/CT). Patients, material, methods: A comprehensive literature search of studies published up to February 2014 was performed. Pooled prevalence and malignancy risk of PIU were calculated on a per patient-based analysis including 95% confidence interval (95%CI). Furthermore, we assessed some parameters as potential predictors of malignant PIU. Results: Six studies including 47925 patients who underwent 18F-FDG PET/CT were selected. Pooled prevalence of PIU was 1.8% (95%CI: 1.3–2.3%). Overall, 444 patients with PIU were further evaluated and 121 underwent biopsy. The pooled risk of malignancy in patients with PIU further evaluated or verified by biopsy were 17% (95%CI: 12–23%) and 62% (95%CI: 54–71%), respectively. A higher mean age was observed in the group of malignant PIUs compared to benign PIUs. There was a trend towards a higher mean SUVmax in the group of malignant PIUs but without a statistically significant difference compared to benign PIUs. Peripheric site of PIU but not presence or absence of calcification was a predictor of malignancy. Conclusions: PIU is observed in about 1.8% of 18F-FDG PET/CT scans performed in male patients carrying a significant risk of malignancy. Therefore, whenever a PIU is detected further investigation is warranted to exclude malignancy, in particular when PIU is located in the peripheric site of prostate gland.