PSA and PSA Kinetics as Predictors for 18F-Fluciclovine PET/CT Positivity in Biochemically Recurrent Prostate Cancer

<b><i>Introduction:</i></b> ¹⁸F-Fluciclovine PET/CT is one of the imaging techniques currently employed to restage prostate cancer (PCa). Due to the conflicting results reported in the literature, it is not yet known at what PSA threshold ¹⁸F-fluciclovine PET/CT could reliably demonstrate the presence of recurring disease. We explored the association between ¹⁸F-fluciclovine PET/CT positivity and prescan PSA, PSA doubling time, and PSA velocity in patients with biochemical recurrence (BCR) of PCa after curative-intent treatment. <b><i>Methods:</i></b> Data from 59 patients who underwent ¹⁸F-fluciclovine PET/CT for BCR after radical prostatectomy or radiotherapy were retrieved from a single institution database. Patients already undergone salvage treatments at the time of PET/CT, with newly diagnosed PCa or with initial diagnosis of metastatic PCa were excluded. A 2-sided independent samples Bayesian <i>t</i> test and Bayesian Mann-Whitney U test were used to assess the association between PET/CT and prescan PSA, PSA doubling time, and PSA velocity. <b><i>Results:</i></b> Evidence for no difference between PET/CT-positive and -negative patients for log-transformed PSA was found (BF₀₁ 3.61, % error: 0.01). Robustness check and sequential analysis showed stability across a wide range of prior distribution specifications. The hypothesis of no difference in terms of PSA-dt and for PSA-vel between groups was found to be more likely compared to the alternative hypothesis (BF₀₁ of 3.44 and 3.48, respectively). <b><i>Conclusion:</i></b> PSA and PSA kinetics are unlikely to be associated with ¹⁸F-fluciclovine PET/CT positivity in patients with BCR, and none of these serum biomarkers might be used as single predictors of PET/CT detection. Larger studies might be needed to evaluate the role of different predictors.

Prostate-Specific Antigen Kinetics Effects on Outcomes of Low-Volume Metastatic Prostate Cancer Patients Receiving Androgen Deprivation Therapy

Background. The present study aimed to analyse factors influencing the effects of androgen deprivation therapy (ADT) in patients with newly diagnosed metastatic castration-naïve prostate cancer (mCNPC), especially in low-volume disease (LVD), according to subclassification of metastatic prostate cancer established by the CHAARTED trial. Materials and Methods. We reviewed 648 patients with newly diagnosed mCNPC receiving ADT at Chang Gung Memorial Hospital from January 2007 to December 2016. Basic characteristics and PSA kinetics profile were subsequently evaluated. Results. 48.3% of LVD patients progressed to castration-resistant prostate cancer (mCRPC). Among them, CRPC group had significantly shorter time to PSA nadir (TTN) and faster time from PSA nadir to CRPC (TFNTC) ( p < 0.001) compared to non-CRPC group. PSA doubling time (PSADT) < 4 months tended to be associated with faster disease progression and shorter overall survival (OS). Among all patients with metastatic prostate cancer, those with shorter TTN <9 months, higher nadir PSA level ≥1 ng/mL, and shorter PSADT <3 months had increased tendency for biochemical progression. Conclusions. PSADT is an effective clinical predictor for disease progression and survival in LVD. Other PSA kinetics including TTN and TFNTC, though not the major predictors for disease progression or OS in LVD, might be the predictors for disease control status.

Tumor volume and prostate-specific antigen kinetics effects on outcomes of metastatic prostate cancer patients receiving androgen deprivation therapy

Background The present study aimed to analyse the effects of androgen deprivation therapy (ADT) in patients with newly diagnosed metastatic castration-naïve prostate cancer (mCNPC) and explore predictors, particularly prostate-specific antigen (PSA) kinetics, associated with poor prognosis according to tumor volume, a new sub-classification of metastatic prostate cancer established by the CHAARTED trial.Methods We reviewed 648 patients with newly diagnosed mCNPC receiving ADT at Chang Gung Memorial Hospital from January 2007 to December 2016. Basic characteristics and PSA kinetics profile were subsequently evaluated.Results Among patients with high-volume disease, those with faster time to PSA nadir (TTN) (< 7 months), higher PSA nadir (≥ 2 ng/mL), and faster PSA doubling time (PSADT) (< 2 months) had higher risk for faster disease progression or shorter overall survival (OS) compared to those with slower TTN (> 7 months), lower PSA nadir (< 2 ng/mL), and slower PSADT (> 2 months). Multivariate analysis of those with low-volume disease showed that only PSADT (< 4 months) was tended to be associated with faster disease progression or shorter OS.Conclusions PSA kinetics are effective clinical predictors for risk of disease progression and survival. Moreover, various PSA kinetics should be monitored according to tumor volume.