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

Purpose: The effectiveness of salvage therapy in prostate cancer is greater for low prostate specific antigen values. Therefore, early detection of tumor recurrence is warranted. [C-11] 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 [C-11] choline positron emission tomography/computerized tomography is desirable to optimize salvage therapy. Materials and Methods: 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 [C-11] choline positron emission tomography/computerized tomography for the restaging of disease. Binary logistic regression was used to assess predictive factors of positive [C-11] choline positron emission tomography/computerized tomography. Included variables were trigger prostate specific antigen, prostate specific antigen doubling time, age, pathological stage and Gleason score. Results: Median prostate specific antigen was 0.61 ng/ml. [C-11] 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 [C-11] 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 [C-11] choline positron emission tomography/computerized tomography increased to 50%. Conclusions: 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 [C-11] choline positron emission tomography/computerized tomography. In these patients [C-11] choline positron emission tomography/computerized tomography may reduce by 50% the number in whom salvage therapy is initiated empirically without knowing the disease location.