Does PSADT after radical prostatectomy correlate with overall survival?--a report from the SEARCH database group

Survival and Economic Impact of Rapid Prostate-Specific Antigen Doubling Time in Patients With Nonmetastatic Castration-Resistant Prostate Cancer

INTRODUCTION

In patients with nonmetastatic castration-resistant prostate cancer (nmCRPC), prostate-specific antigen doubling time (PSADT) is associated with risk of metastasis and survival. This study evaluated the association of PSADT with clinical and economic outcomes in a real-world setting among patients with nmCRPC not receiving novel hormonal therapy (NHT), using 2-month PSADT thresholds.

PATIENTS AND METHODS

We retrospectively identified Veterans Health Administration patients with nonmetastatic prostate cancer and ≥2 PSA increases after medical/surgical castration (2012-2016). The third measurement was the index (CRPC) date. Patients with ≥3 postindex PSA measurements, including index, were followed until death or ≥12 months until disenrollment, study end, or death, and grouped into 2-month cohorts based on postindex PSADT. Cox regression models assessed association between PSADT, time to metastasis, and death. Healthcare resource utilization and costs were evaluated.

RESULTS

Among 2800 evaluable patients, median follow-up was 30 months and median PSADT was 17 months. Relative to the reference cohort (PSADT >12 months), all cohorts had significantly higher metastasis risk. PSADT ≤10-month cohorts had significantly greater mortality risk than the reference; hazard ratios (95% confidence intervals) ranged from 12.3 (9.2, 16.4) in the PSADT ≤2-month cohort to 1.3 (0.9, 2.0) in the >10 to ≤12-month cohort. Total costs were significantly higher for cohorts up to and including the PSADT >8 to ≤10-month cohort, than for the reference cohort. Mean per patient per month all-cause medical plus pharmacy costs were $6623, $4768, and $4049 in the PSADT ≤2-month, >2 to ≤4-month cohort, and >4 to ≤6-month cohorts, respectively, versus $1911 in the PSADT >12-month cohort (P <0.05).

CONCLUSION

Most patients with nmCRPC have PSADT >12 months and a long natural history. For those with shorter PSADT, the risk of metastasis, death, and costs increased. These data can help select patients for NHT and conversely those who can safely delay NHT for nmCRPC.

Assessment of oligometastasis status of prostate cancer following combined robot-assisted radical prostatectomy and androgen deprivation versus androgen deprivation therapy alone using PSA percentage decline rate

OBJECTIVE

To compare the tumor control in prostate cancer patients with oligo-metastasis following combined robot-assisted radical prostatectomy and androgen deprivation versus androgen deprivation therapy alone based on total prostate-specific antigen (tPSA) assessment.

METHODS

Medical data of a total of 18 prostate cancer patients with oligometastasis administered in The First Affiliated Hospital of Nanchang University from March 2017 to March 2018 were prospectively collected. 10 patients received a combined therapy of robot-assisted radical prostatectomy and pharmaceutical androgen deprivation (RARP+ADT group), while 8 patients received pharmaceutical androgen deprivation therapy alone (ADT group). Then demographic characteristics, prostate volume, tumor characteristics and tPSA data were analysised and compared. Statistical analysis was performed using t-test for continuous variables and Pearson chi-square test or Fisher's exact test for categorical variables.

RESULTS

No significant difference was found in patients' age (p = 0.075), prostate volume (p = 0.134) and number of bone metastasis (p = 0.342). Pre-treatment Gleason score was significantly lower in RA group (p = 0.003). Patients in RARP+ADT group had significantly lower pre-treatment tPSA (p = 0.014), while no statistical difference was noted in reexamined tPSA (p = 0.140) on follow-up. No statistical difference was noted in tPSA decline rates (declined tPSA value per day) in RARP+ADT and ADT group (8.1 ± 4.7 verse 7.5 ± 8.0 ng/ml/d, p = 0.853). However, tPSA percentage decline rate (declined tPSA percentage per day) was significantly higher in RARP+ADT group (11.6 ± 1.5%/d verses 2.9 ± 2.2%/d, p< 0.001). Immediate urinary continence was achieved in 9 patients (90%) upon removal of urethral catheter on post-operative day 7 in RARP+ADT group.

CONCLUSION

ADT alone and in combination with RARP both provide effective tumor control in patients suffering from prostate cancer with oligometastasis. ADT combined with RARP exhibited significant advantage in PSA percentage decline rate without compromising patients' urinary continence. Long-term tumor control requires further follow-up.

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).

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.

Thresholds for PSA doubling time in men with non-metastatic castration-resistant prostate cancer

OBJECTIVES

To examine whether prostate-specific antigen doubling time (PSADT) correlates with metastases, all-cause mortality (ACM), and prostate cancer-specific mortality (PCSM) and to identify PSADT thresholds that can be used clinically for risk stratification in men with M0 castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

We collected data on 441 men with M0 CRPC in 2000-2015 at five Veterans Affairs hospitals. Cox models were used to test the association between log-transformed PSADT and the development of metastasis, ACM and PCSM. To identify thresholds, we categorized PSADT into 3-month groups and then combined groups with similar hazard ratios (HRs).

RESULTS

The median (interquartile range) follow-up was 28.3 (14.7-49.1) months. As a continuous variable, PSADT was associated with metastases, ACM and PCSM (HR 1.40-1.68, all P < 0.001). We identified the following PSADT thresholds: <3 months; 3-8.9 months; 9-14. months; and ≥15 months. As a categorical variable, PSADT was associated with metastases, ACM and PCSM (all P < 0.001). Specifically, PSADT <3 months was associated with an approximately ninefold increased risk of metastases (HR 8.63, 95% CI 5.07-14.7) and PCSM (HR 9.29, 95% CI 5.38-16.0), and a 4.7-fold increased risk of ACM (HR 4.71, 95% CI 2.98-7.43) on multivariable analysis compared with PSADT ≥15 months. The median times to metastasis for patients with PSADT <3, 3-8.9, 9-14.9 and ≥15 months were 9, 19, 40 and 50 months, respectively.

CONCLUSION

Prostate-specific antigen doubling time was a strong predictor of metastases, ACM and PCSM in patients with M0 CRPC. As with patients at earlier disease stages, <3, 3-8.9, 9-14.9 and ≥15 months are reasonable PSADT thresholds for risk stratification in men with M0 CRPC. These thresholds can be used for selecting high-risk men for clinical trials.

A combination trial of vaccine plus ipilimumab in metastatic castration-resistant prostate cancer patients: immune correlates

We recently reported the clinical results of a Phase I trial combining ipilimumab with a vaccine containing transgenes for prostate-specific antigen (PSA) and for a triad of costimulatory molecules (PROSTVAC) in patients with metastatic castration-resistant prostate cancer. Thirty patients were treated with escalating ipilimumab and a fixed dose of vaccine. Of 24 chemotherapy-naïve patients, 58 % had a PSA decline. Combination therapy did not exacerbate the immune-related adverse events associated with ipilimumab. Here, we present updated survival data and an evaluation of 36 immune cell subsets pre- and post-therapy. Peripheral blood mononuclear cells were collected before therapy, at 13 days and at 70 days post-initiation of therapy, and phenotyped by flow cytometry for the subsets of T cells, regulatory T cells, natural killer cells, and myeloid-derived suppressor cells. Associations between overall survival (OS) and immune cell subsets prior to treatment, and the change in a given immune cell subset 70 days post-initiation of therapy, were evaluated. The median OS was 2.63 years (1.77-3.45). There were trends toward associations for longer OS and certain immune cell subsets before immunotherapy: lower PD-1(+)Tim-3(NEG)CD4EM (P = 0.005, adjusted P = 0.010), higher PD-1(NEG)Tim-3(+)CD8 (P = 0.002, adjusted P = 0.004), and a higher number of CTLA-4(NEG) Tregs (P = 0.005, adjusted P = 0.010). We also found that an increase in Tim-3(+) natural killer cells post- versus pre-vaccination associated with longer OS (P = 0.0074, adjusted P = 0.015). These results should be considered as hypothesis generating and should be further evaluated in larger immunotherapy trials.

Do nomograms designed to predict biochemical recurrence (BCR) do a better job of predicting more clinically relevant prostate cancer outcomes than BCR? A report from the SEARCH database group

OBJECTIVE

To examine the ability of various postoperative nomograms to predict prostate cancer-specific mortality (PCSM) and to validate that they could predict aggressive biochemical recurrence (BCR). Prostate-specific antigen (PSA), grade, and stage are the classic triad used to predict BCR after radical prostatectomy (RP). Multiple nomograms use these to predict risk of BCR. A previous study showed that several nomograms could predict aggressive BCR (prostate-specific antigen doubling time [PSADT] <9 months) more accurately than BCR. However, it remains unknown if they can predict more definitive endpoints, such as PCSM.

METHODS

We performed Cox analyses to examine the ability of 4 postoperative nomograms, the Duke Prostate Center (DPC) nomogram, the Kattan postoperative nomogram, the Johns Hopkins Hospital (JHH) nomogram, and the joint Center for Prostate Disease Research(CPDR)/Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) nomogram to predict BCR and PCSM among 1778 men in the Shared Equal Access Regional Cancer Hospital (SEARCH) database who underwent RP between 1990 and 2009. We also compared their ability to predict BCR and aggressive BCR in a subset of men. We calculated the c-index for each nomogram to determine its predictive accuracy for estimating actual outcomes.

RESULTS

We found that each nomogram could predict aggressive BCR and PCSM in a statistically significant manner and that they all predicted PCSM more accurately than they predicted BCR (ie, with higher c-index values).

CONCLUSION

Currently available nomograms used to predict BCR accurately predict PCSM and other more clinically relevant endpoints. Moreover, not only do they significantly predict PCSM, but do so with generally greater accuracy than BCR.

A prostate-specific antigen doubling time of <6 months is prognostic for metastasis and prostate cancer-specific death for patients receiving salvage radiation therapy post radical prostatectomy

Background

The ideal prostate-specific antigen (PSA) doubling time (PSADT) threshold for identifying patients at high-risk for poor clinical outcome following salvage radiation therapy (SRT) has not been well established. We sought to assess what PSADT threshold is most clinically prognostic in this setting.

Methods

575 patients who received SRT at a single institution for biochemical recurrence after radical prostatectomy were retrospectively reviewed. We assessed the impact of pre-SRT PSADT on biochemical failure (BF), distant metastasis (DM), prostate cancer-specific mortality (PCSM), and overall mortality (OM). Kaplan-Meier methods, hazard ratio (HR) assessment, and Cox Proportional Hazard models were used to assess the discriminatory ability of various PSADT thresholds.

Results

Sufficient data to calculate PSADTs were available for 277 patients. PSADT was prognostic for BF, DM, PCSM, and OM on univariate analysis regardless of threshold. HR assessment identified 6 months as a strong threshold. No statistically significant difference was observed in BF, DM, PCSM, or OM between patients with PSADT <3 (n=40) and 3–6 months (n=61) or between 6–10 (n=62) and >10 months (n=114). However significant differences were seen in BF (HR:2.2, [95%CI: 1.4-3.5], p<0.01) and DM (HR:2.2, [95%CI: 1.2-4.3], p=0.02) between a PSADT of 3–6 and 6–10 months. On multivariate analysis a PSADT <6 months predicted BF (HR:2.0, [95%CI: 1.4-2.9], p=0.0001), DM (HR:2.0, [95%CI: 1.2-3.4], p=0.01), and PCSM (HR:2.6, [95%CI: 1.1-5.9], p=0.02).

Conclusions

A pre-SRT PSADT <6 months was a strong predictor of outcomes in our data set, including PCSM. The most common nomogram for SRT uses a 10-month PSADT threshold for assigning points used to assess BF following SRT. If validated, our findings suggest that a PSADT threshold of <6 months should be considered for stratification of patients in future clinical trials in this setting.

Dutasteride treatment over 2 years delays prostate-specific antigen progression in patients with biochemical failure after radical therapy for prostate cancer: results from the randomised, placebo-controlled Avodart After Radical Therapy for Prostate Cancer Study (ARTS)

BACKGROUND

Rising prostate-specific antigen (PSA) levels after radical therapy are indicative of recurrent or residual prostate cancer (PCa). This biochemical recurrence typically predates clinically detectable metastatic disease by several years. Management of patients with biochemical recurrence is controversial.

OBJECTIVE

To assess the effect of dutasteride on progression of PCa in patients with biochemical failure after radical therapy.

DESIGN, SETTING, AND PARTICIPANTS

Randomised, double-blind, placebo-controlled trial in 294 men from 64 centres across 9 European countries.

INTERVENTION

The 5α-reductase inhibitor, dutasteride.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was time to PSA doubling from start of randomised treatment, analysed by log-rank test stratified by previous therapy and investigative-site cluster. Secondary end points included time to disease progression and the proportion of subjects with disease progression.

RESULTS AND LIMITATIONS

Of the 294 subjects randomised (147 in each treatment group), 187 (64%) completed 24 mo of treatment and 107 discontinued treatment prematurely (71 [48%] of the placebo group, 36 [24%] of the dutasteride group). Dutasteride significantly delayed the time to PSA doubling compared with placebo after 24 mo of treatment (p<0.001); the relative risk (RR) reduction was 66.1% (95% confidence interval [CI], 50.35-76.90) for the overall study period. Dutasteride also significantly delayed disease progression (which included PSA- and non-PSA-related outcomes) compared with placebo (p<0.001); the overall RR reduction in favour of dutasteride was 59% (95% CI, 32.53-75.09). The incidence of adverse events (AEs), serious AEs, and AEs leading to study withdrawal were similar between the treatment groups. A limitation was that investigators were not blinded to PSA levels during the study.

CONCLUSIONS

Dutasteride delayed the biochemical progression of PCa in patients with biochemical failure after radical therapy for clinically localised disease. The safety and tolerability of dutasteride were generally consistent with previous experience.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT00558363.

Prognostic factors in Chinese patients with metastatic castration-resistant prostate cancer treated with docetaxel-based chemotherapy

This study aims to evaluate the potential value of patient characteristics in predicting overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel-based thermotherapy. A total of 115 patients with mCRPC undergoing a docetaxel q3w regimen were enrolled in this study. A survival analysis was performed using the Kaplan-Meier method. Cox proportional hazards models were used to evaluate the prognostic value of all covariates for OS. OS was also analysed after stratifying patients according to the results of multivariate analysis. The median OS for the entire cohort was 17.0 months. The multivariate analysis showed that the prostate-specific antigen doubling time (PSADT), baseline haemoglobin (Hb) concentration, alkaline phosphatase (ALP) concentration, cycles of chemotherapy and time to castration resistance were independent prognostic factors of OS. According to the presence of PSADT <46.3 days and baseline ALP ≥ 110 IU l(-1), all patients were divided into three risk groups: low-risk group (no risk factors), intermediate-risk group (one risk factor) and high-risk group (two risk factors). Median OSs for patients in low-, intermediate- and high-risk groups were 28.0 months (95% CI: 23.8-32.2), 21.0 months (95% CI: 18.9-23.1) and 11.0 months (95% CI: 7.6-14.4), respectively (P<0.001). In conclusion, PSADT, baseline Hb concentration, ALP concentration, cycles of chemotherapy and time to castration resistance were independent prognostic factors of OS in Chinese patients with mCRPC treated with docetaxel. PSADT combined with the baseline ALP concentration could be a useful risk stratification parameter for evaluating survival outcomes.

The prognostic factors of effective ketoconazole treatment for metastatic castration-resistant prostate cancer: who can benefit from ketoconazole therapy?

We investigated the prognostic value of some variables of effective ketoconazole treatment for metastatic castration-resistant prostate cancer (mCRPC). In total, 163 patients with mCRPC were eligible, receiving ketoconazole 200-400 mg three times daily with replacement doses of prednisone. Progression-free survival (PFS) was calculated from the beginning of the ketoconazole therapy to the onset of disease progression. The prognostic value of different variables for PFS was assessed by Cox regression analysis. The median PFS was 2.6 months (0.5-8.6 months) for these patients. The serum testosterone level changed during therapy, which decreased when the prostate-specific antigen (PSA) declined; the serum testosterone level increased as the levels of PSA relapsed. The median PFS values for patients associated with different factors were the following: 1.4 and 3.5 months for a nadir PSA of ≥ 0.2 and <0.2 ng ml(-1), respectively (hazard rate (HR)=4.767, P<0.001); 3.1 and 1.6 months for a baseline testosterone of ≥ 0.1 and <0.1 ng ml(-1), respectively (HR=2.865, P=0.012); 2.8 and 1.9 months for a baseline haemoglobin of ≥ 120 and <120 g l(-1), respectively (HR=1.605, P<0.001); and 3.0 and 1.9 months for a PSA doubling time (PSADT) of ≥ 2.0 and <2.0 months, respectively (HR=1.454, P=0.017). A risk model was constructed according to the four factors that divided patients into three subgroups of low risk (0-1 factors), moderate risk (2 factors) and high risk (3-4 factors) with PFS values of 3.6, 3.0 and 1.4 months, respectively (HR=1.619, P<0.001). A nadir PSA of ≥ 0.2 ng ml(-1), a baseline testosterone of <0.1 ng ml(-1), a baseline haemoglobin of <120 g l(-1) and a PSADT of <2 months were associated with a poor PFS. This risk model could provide evidence to predict the survival benefit of ketoconazole therapy.

Does salvage radiation therapy change the biology of recurrent prostate cancer based on PSA doubling times? Results from the SEARCH database

OBJECTIVE

To investigate whether salvage radiation therapy (SRT) may promote prostate cancer (PCa) transformation to more aggressive phenotypes. To accomplish that, we identified men who underwent SRT after radical prostatectomy for PCa and failed SRT. PSA doubling time (PSADT) was used as a surrogate endpoint for cancer aggressiveness. We compared PSADT calculated before start of SRT and after SRT failure.

METHODS

Of 287 men in the SEARCH database since 1988 who underwent SRT, we detected 78 with SRT failure defined as PSA ≥ 0.2 ng/mL above the post-SRT nadir. Of these, 39 had PSADT available before and after SRT, which was compared using Wilcoxon's paired test with men serving as their own controls. We tested predictors of PSADT change using multivariable logistic regression.

RESULTS

There were no differences in PSADT before and after SRT (10.2 vs 12.6 months; P = .46). However, in some individual cases, large changes were observed. Only seminal vesicle invasion showed a trend towards an association with a shorter post-SRT PSADT relative to the pre-SRT PSADT (P = .13).

CONCLUSION

Overall, the PSADT after and before SRT were statistically identical, suggesting that after SRT failure, PCa does not emerge with more aggressive biological features. Further studies are needed to identify predictors and the clinical relevance of individual PSADT changes noted in our study.