Current Role of PSA Kinetics in the Management of Patients with Prostate Cancer

Longitudinal CTCs gene expression analysis on metastatic castration-resistant prostate cancer patients treated with docetaxel reveals new potential prognosis markers

CTCs have extensively been used for the monitoring and characterization of metastatic prostate cancer, but their application in the clinic is still very scarce. Besides, the resistance mechanisms linked to prostate cancer treatment remain unclear. Liquid biopsies represent the most promising alternative due to the complexity of biopsying bone metastasis and the duration of the disease. We performed a prospective longitudinal study in CTCs from 20 castration-resistant prostate cancer patients treated with docetaxel. For that, we used CellSearch® technology and a custom gene expression panel with qRT-PCR using a CTCs negative enrichment approach. We found that CTCs showed a hybrid phenotype during the disease, where epithelial features were associated with the presence of ≥ 5 CTCs/7.5 mL of blood, while high relative expression of the gene MYCL was observed preferentially in the set of samples with < 5 CTCs/7.5 mL of blood. At baseline, patients whose CTCs had stem or hybrid features showed a later progression. After 1 cycle of docetaxel, high relative expression of ZEB1 indicated worse outcome, while KRT19 and KLK3 high expression could predisposed the patients to a worse prognosis at clinical progression. In the present work we describe biomarkers with clinical relevance for the prediction of early response or resistance in castration-resistant prostate cancer patients. Besides, we question the utility of targeted isolated CTCs and the use of a limited number of markers to define the CTCs population.

The utility of PSA velocity in prediction of prostate cancer and high grade cancer after an initially negative prostate biopsy

BACKGROUND

Prostate specific antigen kinetics (PSAK) including prostate specific antigen velocity (PSAV) and PSA doubling time (PSADT) are used as predictors of prostate cancer (PCa) therapeutic outcome, disease prognosis, and cancer-specific mortality. However controversy persists regarding use of these parameters in cancer detection. Our aim is to evaluate PSAV as a predictor of PCa and intermediate/high grade PCa (HGPCa).

METHODS

We included 682 patients that underwent repeat transrectal ultrasound guided biopsy after initial negative biopsy. Univariate and multivariate analyses as well as area under the receiver operating characteristic curve (ROC-AUC) were performed to assess predictive accuracy regarding detection of PCa and intermediate/HGPCa (Gleason score ≥ 7).

RESULTS

PCa was detected in 179/682 (26.24%) patients. Our univariate analysis suggested that age, total prostate volume (TPV), atypical small acinar proliferation (ASAP) and PSA indices in the form of PSA at the time of repeat biopsy (PSA2), PSAV, PSA density (PSAD2) and percent free PSA at time of repeat biopsy (%FPSA2) were all predictors of overall PCa and intermediate/HGPCa. Meanwhile, our multivariate model showed that factors associated with overall PCa and intermediate/HGPCa were age, PSAV and TPV.

CONCLUSIONS

In men pursuing a second biopsy after an initial negative biopsy, PSAV was an independent predictor of overall PCa, intermediate and high grade cancer.