Predictive factors of

backgroundThe objective of this study is to explore the impact of PSA nadirs on detection rates of prostate cancer (PCa) recurrence with

methodsIn this retrospective study, data were collected from 54 patients with suspicion of PCa biochemical recurrence after EBRT (28 patients treated initially with EBRT and 26 as salvage therapy in the absence of PSA decrease after initial treatment), who underwent

resultsMedian PSA nadir was 0.31 (0.01-13.31) ng/mL, trigger PSA was 7.85 (0.47-111.60) ng/mL, and relative PSA was 6.05 (0.24-104.59) ng/mL. Overall, 40 (74%) PET/CT scans were positive: recurrence was local and/or regional in 29 patients, distant in 15 and combined both in four, with no association between PSA values and sites of recurrence. In univariate analysis, trigger (p = 0.015) and relative (p = 0.0005) PSA values and PSA velocity (p = 0.01) were significantly linked to positive PET/CT, but PSA nadir was not. In subgroup analysis, these significant differences were only found in the salvage EBRT group. Akaike Information Criterion multivariate model comparison found that relative PSA was a better predictor of positive PET/CT than trigger PSA (PSAt).

conclusionsWe found a high overall detection rate and an increase in detection rates proportional to trigger and relative PSAs. Although relative PSA, taking into account PSA nadir, was a better predictive factor of PET/CT positivity in univariate analysis, this was most noticeable for high PSAs. For low PSAs, trigger PSA remains most relevant. Larger series with intermediate PSA values need to be studied to fully apprehend nadir impact.