11C]Choline Positron Emission Tomography/Computerized Tomography for Early Detection of Prostate Cancer Recurrence in Patients with Low Increasing Prostate Specific Antigen

Abstract

The effectiveness of salvage therapy in prostate cancer is greater for low prostate specific antigen values. Therefore, early detection of tumor recurrence is warranted. [(11)C]choline positron emission tomography/computerized tomography has the potential of early restaging of prostate cancer with low prostate specific antigen, but the selection of patients at high risk for positive [(11)C]choline positron emission tomography/computerized tomography is desirable to optimize salvage therapy. This retrospective study included 75 patients with prostate cancer with an increasing prostate specific antigen less than 1.5 ng/ml after radical prostatectomy who never received antiandrogen deprivation therapy or salvage radiotherapy who underwent [(11)C]choline positron emission tomography/computerized tomography for the restaging of disease. Binary logistic regression was used to assess predictive factors of positive [(11)C]choline positron emission tomography/computerized tomography. Included variables were trigger prostate specific antigen, prostate specific antigen doubling time, age, pathological stage and Gleason score. Median prostate specific antigen was 0.61 ng/ml. [(11)C]choline positron emission tomography/computerized tomography was positive in 16 of 75 patients (21%). On univariate analysis prostate specific antigen doubling time less than 6 months was the only factor significantly associated with an increased risk of positive [(11)C]choline positron emission tomography/computerized tomography (OR 7.77, 95% CI 2.34-25.80, p = 0.001). In patients with prostate specific antigen doubling time less than 6 months, the positive detection rate of [(11)C]choline positron emission tomography/computerized tomography increased to 50%. In patients with prostate cancer with biochemical failure after radical prostatectomy and prostate specific antigen less than 1.5 ng/ml, prostate specific antigen doubling time less than 6 months predicts positive [(11)C]choline positron emission tomography/computerized tomography. In these patients [(11)C]choline positron emission tomography/computerized tomography may reduce by 50% the number in whom salvage therapy is initiated empirically without knowing the disease location.