Abstract
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Objectives: The purpose of this study is to evaluate the detection rate of 18F-Fluciclovine PET/CT relative to the level of PSA in patients with biochemical recurrence of prostate cancer, with a focus on low PSA levels (< 1 ng/mL). Materials and Methods: This is a retrospective study of consecutive 103 male patients who underwent 18F-Fluciclovine PET/CT for biochemical recurrence of prostate cancer between February 2018 and January 2019 at our institution. Patient demographics, prior PSA, clinical information including prior treatment was recorded. Scans were deemed positive if definitive lesions were noted at the prostate bed, pelvic lymph nodes, skeleton, or other organs. Detection rate was the ratio of positive over total scans and was calculated for different PSA ranges (less than 1 ng/mL, 1 to less than 2 ng/mL, 2 to less than 5 ng/mL, and 5 or more ng/mL). The subgroup of PSA less than 1 ng/mL was subsequently analyzed separately.
Results: The median PSA is 2.5 (ranging from <0.1 to 58 ng/mL). The overall detection rate for all PSA levels combined was 59.2% (n=61/103). The detection rate for different PSA ranges are detailed in table 1. The analysis of the low PSA range (< 1ng/mL) is detailed in table 2. In this subgroup, the detection rate for PSA levels less than 0.7 ng/mL is 17.4% (n=4/23) versus 62.5% for PSA levels of 0.7 to less than 1 ng/mL.
Conclusions: 18F-Fluciclovine PET/CT detection rate increases with increasing PSA levels. In the low PSA range (<1 ng/mL), the detection rate is significantly higher for PSA levels of 0.7 to less than 1 ng/mL. The scan is of limited value when PSA levels are less than 0.7 ng/mL.