Does early prostate-specific antigen doubling time (ePSADT) after radical prostatectomy, calculated using PSA values from the first detectable until the first recurrence value, correlate with standard PSADT? A report from the Shared Equal Access Regional Cancer Hospital Database Group

Integrating Prostate-specific Antigen Kinetics into Contemporary Predictive Nomograms of Salvage Radiotherapy After Radical Prostatectomy

BACKGROUND

Salvage radiotherapy (SRT) is an established treatment for men with biochemical recurrence following radical prostatectomy (RP). There are several risk factors associated with adverse outcomes; however, the value of postoperative prostate-specific antigen (PSA) kinetics is less clear in the ultrasensitive PSA era.

OBJECTIVE

To characterize the impact of PSA kinetics on outcomes following SRT and generate nomograms to aid in identifying patients with an increased risk of adverse clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A multi-institutional analysis was conducted of 1005 patients with prostate cancer treated with SRT after RP, with a median follow-up of 5 years.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Variables examined include immediate postoperative PSA, postoperative PSA doubling time (DT), and pre-SRT PSA, in addition to previously identified predictive factors. Multivariable survival analyses were completed using Fine-Gray competing risk regression. Rates of biochemical failure (BF), distant metastasis (DM), and prostate cancer-specific mortality (PCSM) were estimated by the cumulative incidence method. Nomograms were generated from multivariable competing risk regression with bootstrap cross-validation.

RESULTS AND LIMITATIONS

Factors associated with BF after SRT include PSA DT <6 mo, initial postoperative PSA ≥0.2 ng/ml, higher pre-SRT PSA, lack of androgen deprivation therapy, a higher Gleason score (GS), negative margins, seminal vesicle invasion, lack of pelvic nodal radiation, radiation total dose <66 Gy, a longer RP to SRT interval, and older age (p < 0.05 for each). Factors associated with DM include PSA DT <6 mo, pre-SRT PSA, a higher GS, and negative margins. Factors associated with PCSM include PSA DT not calculable or <6 mo and a higher GS. Nomograms were generated to estimate the risks of BF (concordance index [CI] 0.74), DM (CI 0.77), and PCSM (CI 0.77). Limitations include retrospective nature, broad treatment eras, institutional variations, and multiple methods available for the estimation of PSA DT.

CONCLUSIONS

Postoperative PSA kinetics, particularly pre-SRT PSA and PSA DT, are strongly associated with adverse oncologic outcomes following SRT and should be considered in management decisions.

PATIENT SUMMARY

In this report of men with prostate cancer who developed a prostate-specific antigen (PSA) recurrence after prostatectomy, we found that PSA levels after surgery and how quickly a PSA level doubles significantly impact the chance of prostate cancer recurrence after salvage radiation therapy. Based on this information, we created a tool to calculate a man's chance of cancer recurrence after salvage radiation therapy, and these estimations can be used to discuss whether additional treatment with radiation should be considered.

CD8+ T Cells Impact Rising PSA in Biochemically Relapsed Cancer Patients Using Immunotherapy Targeting Tumor-Associated Antigens

The management of men with prostate cancer (PCa) with biochemical recurrence following local definitive therapy remains controversial. Early use of androgen deprivation therapy (ADT) leads to significant side effects. Developing an alternative, clinically effective, and well-tolerated therapy remains an unmet clinical need. INO-5150 is a synthetic DNA therapy that includes plasmids encoding for prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA), and INO-9012 is a synthetic DNA plasmid encoding for interleukin-12 (IL-12). This phase 1/2, open-label, multi-center study enrolled men with PCa with rising PSA after surgery and/or radiation therapy. Patients were enrolled into one of four treatment arms: arm A, 2 mg of INO-5150; arm B, 8.5 mg of INO-5150; arm C, 2 mg of INO-5150 + 1 mg of INO-9012; and arm D, 8.5 mg of INO-5150 + 1 mg of INO-9012. Patients received study drug with electroporation on day 0 and on weeks 3, 12, and 24, and they were followed for up to 72 weeks. Sixty-two patients were enrolled. Treatment was well tolerated. 81% (50/62) of patients completed all visits. 85% (53/62) remained progression-free at 72 weeks. PSA doubling time (PSADT) was increased when assessed in patients with day 0 PSADT ≤12 months. Immunogenicity was observed in 76% (47/62) of patients by multiple assessments. Analysis indicated that CD38 and perforin co-positive CD8 T cell frequency correlated with attenuated PSA rise (p = 0.05, n = 50).

Salvage radiotherapy in prostate cancer patients with biochemical relapse after radical prostatectomy : Prolongation of prostate-specific antigen doubling time in patients with subsequent biochemical progression

BACKGROUND

In patients with prostate cancer (PCa) and biochemical progression (BP) after radical prostatectomy (RP), salvage radiotherapy (sRT) improves prostate cancer-specific survival (PCSS), but this evidence is based only on retrospective data.

PATIENTS AND METHODS

In addition to our previous study of 151 patients with PCa and BP after RP, we performed univariate analyses of prostate-specific antigen (PSA) kinetics during sRT. In 11 patients with BP or initiation of hormonal treatment (HT) within 180 days after sRT, risk factors were assessed using Mann-Whitney U tests. PSA doubling times (PSADT) before and after sRT in 82 patients with BP after sRT were compared by a Wilcoxon test.

RESULTS

After a median follow-up of 82 months, analysis of PSA kinetics during sRT did not show a statistically significant impact on a subsequent BP, PCSS, or overall survival at an administered dose of 30 or 45 Gy. The subgroup analysis of patients with early BP or early HT revealed higher Gleason scores (p = 0.008) and preoperative PSA values (p = 0.005), shorter PSADT prior to sRT (p < 0.0005), and longer time intervals from RP until the start of sRT (p = 0.005) compared to all other patients. In patients with subsequent BP, PSADTs were significantly prolonged after sRT (median PSADT 4.5 months before and 9.9 months after sRT, p < 0.0005).

CONCLUSION

PSA monitoring during sRT did not predict the therapeutic success. Subgroup analysis suggests a lower probability of benefit for patients with the abovenamed risk factors . However, the prolonged PSADT after sRT reflects a benefit of sRT for the vast majority of patients.

Does Early Prostate Specific Antigen Doubling Time after Radical Prostatectomy, Calculated Prior to Prostate Specific Antigen Recurrence, Correlate with Prostate Cancer Outcomes? A Report from the SEARCH Database Group

PURPOSE

Short prostate specific antigen doubling time following recurrence after radical prostatectomy portends a poor prognosis. Prostate specific antigen doubling time is traditionally calculated using prostate specific antigen values 0.2 ng/ml or greater. We determined whether early prostate specific antigen doubling time, calculated from the first detectable postoperative prostate specific antigen up to and including the first recurrence value, correlates with prostate cancer outcomes.

MATERIALS AND METHODS

Cox models were used to examine the association between early prostate specific antigen doubling time and castration resistant prostate cancer, metastases, and all cause and prostate cancer specific mortality in 674 men who underwent radical prostatectomy between 1988 and 2014 and had a biochemical recurrence. Early prostate specific antigen doubling time was examined as a log transformed continuous and a categorical variable.

RESULTS

After adjusting for multiple clinicopathological characteristics, log transformed early prostate specific antigen doubling time was not associated with any outcome. However, when early doubling time was categorized as 15 or greater, 9 to 14.9, 3 to 8.9 and less than 3 months, on multivariable analysis men with early doubling time less than 3 months were at increased risk for castration resistant prostate cancer (HR 6.20, p = 0.004), metastases (HR 5.26, p = 0.001), prostate cancer specific mortality (HR 5.06, p = 0.026) and all cause mortality (HR 1.63, p = 0.065) compared to those with an early doubling time of 15 months or greater. However, the association with all cause mortality was not significant. Those with an early prostate specific antigen doubling time of 3 to 8.9 months were at increased risk for castration resistant prostate cancer (HR 3.56, p = 0.015), all cause mortality (HR 1.67, p = 0.006) and prostate cancer specific mortality (HR 3.17, p = 0.044) but not metastases (p = 0.13).

CONCLUSIONS

Early prostate specific antigen doubling time less than 9 months, calculated using prostate specific antigen values before and up to biochemical recurrence, is associated with an increased risk of castration resistant prostate cancer, metastases, and prostate cancer specific and all cause mortality among men with biochemical recurrence after radical prostatectomy. Early prostate specific antigen doubling time allows for risk stratification at biochemical recurrence and before prostate specific antigen doubling time is calculable, enabling these men to be referred for early aggressive secondary treatment and/or clinical trials.

Longitudinal modeling of ultrasensitive and traditional prostate-specific antigen and prediction of biochemical recurrence after radical prostatectomy

Ultrasensitive prostate-specific antigen (u-PSA) remains controversial for follow-up after radical prostatectomy (RP). The aim of this study was to model PSA doubling times (PSADT) for predicting biochemical recurrence (BCR) and to capture possible discrepancies between u-PSA and traditional PSA (t-PSA) by utilizing advanced statistical modeling. 555 RP patients without neoadjuvant/adjuvant androgen deprivation from the Turku University Hospital were included in the study. BCR was defined as two consecutive PSA values >0.2 ng/mL and the PSA measurements were log₂-transformed. One third of the data was reserved for independent validation. Models were first fitted to the post-surgery PSA measurements using cross-validation. Major trends were then captured using linear mixed-effect models and a predictive generalized linear model effectively identified early trends connected to BCR. The model generalized for BCR prediction to the validation set with ROC-AUC of 83.6% and 95.1% for the 1 and 3 year follow-up censoring, respectively. A web-based tool was developed to facilitate its use. Longitudinal trends of u-PSA did not display major discrepancies from those of t-PSA. The results support that u-PSA provides useful information for predicting BCR after RP. This can be beneficial to avoid unnecessary adjuvant treatments or to start them earlier for selected patients.

Therapeutic targeting of angiotensin II receptor type 1 to regulate androgen receptor in prostate cancer

BACKGROUND

With the limited strategies for curative treatment of castration-resistant prostate cancer (CRPC), public interest has focused on the potential prevention of prostate cancer. Recent studies have demonstrated that an angiotensin II receptor blocker (ARB) has the potential to decrease serum prostate-specific antigen (PSA) level and improve performance status in CRPC patients. These facts prompted us to investigate the direct effects of ARBs on prostate cancer growth and progression.

METHODS

Transgenic rat for adenocarcinoma of prostate (TRAP) model established in our laboratory was used. TRAP rats of 3 weeks of age received ARB (telmisartan or candesartan) at the concentration of 2 or 10 mg/kg/day in drinking water for 12 weeks. In vitro analyses for cell growth, ubiquitylation or reporter gene assay were performed using LNCaP cells.

RESULTS

We found that both telmisartan and candesartan attenuated prostate carcinogenesis in TRAP rats by augmentation of apoptosis resulting from activation of caspases, inactivation of p38 MAPK and down-regulation of the androgen receptor (AR). Further, microarray analysis demonstrated up-regulation of estrogen receptor β (ERβ) by ARB treatment. In both parental and androgen-independent LNCaP cells, ARB inhibited both cell growth and AR-mediated transcriptional activity. ARB also exerted a mild additional effect on AR-mediated transcriptional activation by the ERβ up-regulation. An intervention study revealed that PSA progression was prolonged in prostate cancer patients given an ARB compared with placebo control.

CONCLUSION

These data provide a new concept that ARBs are promising potential chemopreventive and chemotherapeutic agents for prostate cancer.

Nucleic Acid Detection Immunoassay for Prostate-Specific Antigen Based on Immuno-PCR Methodology

BACKGROUND

Serum prostate-specific antigen (PSA) concentrations after radical prostatectomy typically become undetectable with the use of current immunometric assay methods. Despite modern surgical techniques, 15%–30% of prostate cancer patients undergoing radical prostatectomy develop a biochemical recurrence during follow-up. Unfortunately, poor analytical sensitivity of standard PSA assays delays biochemical recurrence detection, and because of day-to-day assay imprecision ultrasensitive PSA assays cannot assess PSA kinetics. We developed an immuno-PCR assay for total PSA that has a limit of quantification &gt;10 times lower than current ultrasensitive assays.

METHODS

The 2-site immunometric assay for total PSA employed 2 monoclonal antibodies, one conjugated to a double-stranded DNA label and the other bound to paramagnetic microparticles. After several washing steps, quantification cycles were determined and values were converted to PSA concentrations. We characterized analytical performance and compared accuracy with a commercially available total PSA assay.

RESULTS

The limit of quantification was 0.65 ng/L and the assay was linear in the range of 0.25–152.0 ng/L. Total imprecision estimates at PSA concentrations of 3.8, 24.1, and 69.1 ng/L were &lt;15.2%, &lt;9.4%, and &lt;10.6%, respectively. Recovery of supplemented PSA ranged from 87.5% to 119.2% (mean 100.3%). Dilution recovery ranged from 96.4% to 115.3% (mean 102.3%). There was no high-dose hook effect up to 50 000 ng/L of PSA. Comparison with the commercial PSA assay showed a regression slope of 1.06 and a correlation coefficient of 0.996.

CONCLUSIONS

The analytical characteristics of the assay support the use of this assay for the accurate and precise measurement of serum PSA, even at sub–nanogram-per-liter concentrations.

Freedom from a detectable ultrasensitive prostate-specific antigen at two years after radical prostatectomy predicts a favorable clinical outcome: analysis of the SEARCH database

OBJECTIVES

To assess the utility of kinetics for ultrasensitive prostate-specific antigen (uPSA) assays to identify men who are at risk of developing high-risk recurrent prostate cancer [prostate-specific antigen doubling time (PSADT) < 9 months] after radical prostatectomy. Previous studies demonstrate that a PSADT < 9 months after radical prostatectomy is associated with prostate cancer-specific mortality. Conventionally, PSADT has been calculated after biochemical failure (PSA > or = 2 0.2 ng/mL).

METHODS

A review of the Shared Equal Access Regional Cancer Hospital database from 1988-2008 was performed to identify men with biochemical failure after radical prostatectomy and > or = 2 uPSA values before failure (PSA > or = 2 0.2 ng/mL) as well as > or = 2 2 values after failure to calculate PSADT. These patients were stratified into low-risk (PSADT > or = 2 9 months) and high-risk (PSADT < 9 months) cohorts. The following uPSA kinetics were analyzed for their ability to predict low- and high-risk cohorts: time to first detectable uPSA, time from uPSA to biochemical failure, uPSA velocity, uPSADT, uPSA exponential rise, and uPSA fluctuations.

RESULTS

The analysis included 89 low- and 26 high-risk men. Time to first detectable uPSA was inversely associated with the high-risk cohort (OR 0.96, 95% CI 0.92-0.99, P = .02) and characterized by a high sensitivity and negative predictive value at a threshold of 2 years after surgery. Other measures of uPSA kinetics showed no association with PSADT.

CONCLUSIONS

Time to first detectable uPSA identifies men with low-risk recurrence prostate cancer. Patients with an undetectable uPSA 2 years after surgery are unlikely to develop PSADT < 9 months after biochemical failure.