Fluorodeoxyglucose positron emission tomography may aid the diagnosis of aggressive primary prostate cancer: A case series study

Abstract

Recent evidence has shown that positive results may be observed for fluorodeoxyglucose-positron emission tomography (FDG-PET) in undifferentiated, biologically aggressive and metastatic tumors. The present study describes a case series of six patients with normal prostate-specific antigen (PSA) serum levels who underwent FDG-PET due to other causes. Positive PET results were observed at the prostate and the patients were subsequently diagnosed with high-risk prostate cancer. Clinical, anamnestic, laboratory and instrumental data were collected from six asymptomatic patients with total serum PSA levels of <4 ng/ml who had undergone FDG-PET due to other causes. The FDG-PET and prostate biopsy were positive for prostate cancer. All the patients were treated with radical intent. The median age was 66 years (range, 52–72 years), the median total PSA value was 2.4 ng/ml (range, 1.5–3.9 ng/ml) and the body mass index was 26.4 (range, 21.8–30.2). Three of the six patients underwent FDG-PET due to a clinical suspicion of multiple myeloma, while three patients were examined for other oncological diseases. The pathological analysis at the prostate biopsy revealed three patients with a Gleason score of 6, two with a score of 7 (4+3) and one with a score of 8 (4+4). Five of the six patients were treated by radical prostatectomy and one by radiotherapy. The pathological analysis revealed one patient of pT2a stage, three of pT2c and one of pT3b. No patients demonstrated lymph node invasion. The definitive Gleason score was 3+3 in one patient, 4+3 in one patient, 4+4 in two patients and 5+3 in one patient. Following a median follow-up time of six months (range, 1–12 months), five of the six patients underwent FDG-PET again, which revealed negative results. At the end of this study, these patients were alive without evidence of disease. By contrast, one patient demonstrated positive FDG-PET results. In conclusion, FDG-PET has been used to characterize prostate cancers in patients with apparently normal PSA levels.