Implications of Prostate-Specific Antigen Doubling Time as Indicator of Failure after Surgery or Radiation Therapy for Prostate Cancer

Appropriate definition of non-metastatic castration-resistant prostate cancer (nmCRPC) and optimal timing of androgen receptor signaling inhibitor (ARSI)

BACKGROUND

Defined by rising PSA levels under androgen deprivation therapy (ADT) despite no visible metastases on conventional imaging, non-metastatic castration-resistant prostate cancer (nmCRPC) represents a complex clinical challenge. A significant subset of these patients rapidly develops metastatic disease, negatively impacting survival. We examined the difference in prognosis of nmCRPC patients according to the timing of therapeutic interventions with androgen receptor signaling inhibitor (ARSI).

METHODS

We examined 102 nmCRPC patients treated with ARSI. We divided patients according to their PSA levels when ARSI was administered: Cohort A (PSA 0.5-2.0 ng/mL), Cohort B (PSA 2.0-4.0 ng/mL), and Cohort C (PSA > 4.0 ng/mL). Utilizing the Kaplan-Meier method for survival analysis, our analytical starting point was the moment when PSA levels exceeded 0.5 ng/mL post-ADT nadir, ensuring a fair comparison and minimizing lead-time bias.

RESULTS

After excluding 5 patients whose PSA nadir after ADT > 0.5 ng/mL, patient distribution across Cohort A, Cohort B, and Cohort C was 32, 24, and 41 patients, respectively. Kaplan-Meier survival analysis highlighted a 2-year metastasis-free survival rate of 97% for Cohort A, 87% for Cohort B, and 73% for Cohort C. A marked statistical difference emerged when comparing Cohort A with Cohorts B and C, with a p-value of 0.043.

CONCLUSION

The timely initiation of ARSI is paramount in nmCRPC management. Our findings strongly advocate for consideration of ARSI administration in nmCRPC patients before their PSA levels exceed 2.0 ng/mL. Our results indicated a PSA threshold of 1.0 ng/mL for nmCRPC definition which is more reasonable to administer ARSI without delay.

Nonmetastatic Castration-Resistant Prostate Cancer: Current Challenges and Trends

Prostate carcinoma is a highly prevalent biologically and clinically diverse disease, generally associated with a consistent elevation of prostate-specific antigen levels. Castration-resistant prostate cancer represents a heterogeneous clinical setting that ranges from patients with an asymptomatic prostate-specific antigen elevation after hormone blockade failure and good performance status to patients with significant debilitating symptoms and rapidly progressive disease, leading to death. Nonmetastatic castration-resistant prostate cancer is a transient disease stage defined over specific criteria established within a sensitive time period. The majority of the patients with nonmetastatic castration-resistant prostate cancer will eventually develop metastatic lesions, associated with prostate cancer-specific morbidity and mortality. However, progression to metastatic disease is a heterogeneous process still not fully understood, with studies suggesting that younger age, high Gleason score (> 7), high prostate-specific antigen levels, reduced prostate-specific antigen doubling time (< 6 months), and a rapid alkaline phosphatase rise as potentially associated factors. Although the nonmetastatic castration-resistant prostate cancer treatment landscape has substantially evolved in recent years, the disease heterogeneity makes treatment decisions for this population challenging in the effort to achieve a balance between the risk of disease progression and the toxicity of new treatments in patients who often have associated comorbidities, yet are generally asymptomatic. The present article addresses the current main challenges in nonmetastatic castration-resistant prostate cancer management, including in diagnosis, owing to the development of new imaging modalities with a direct impact in disease detection, prognostic classification, as a result of the traditionally oversimplified definition of disease aggressiveness (mainly based on prostate-specific antigen doubling time), and patient selection for the most adequate treatment.

Negative impact of neoadjuvant hormonal therapy on detecting biochemical recurrence after radical prostatectomy

Background

Routine use of neoadjuvant hormonal therapy (NHT) before radical prostatectomy (RP) is not recommended, but it is sometimes performed to reduce the prostate size and tumor volume or to prevent tumor progression during the wait times for surgery in clinical practice. On the other hand, the impact of NHT on the pattern of biochemical recurrence (BCR) is unknown.

Methods

We retrospectively examined 1749 consecutive patients who underwent RP between 1996 and 2017. Among the patients who met the inclusion criteria, BCR developed in 240 of non-NHT patients and in 120 of NHT patients during the mean follow-up period of 6.9 years. We examined the impact of NHT on the PSA-doubling time (DT) following BCR at different times after RP.

Results

The median PSA-DTs in non-NHT patients who experienced BCR in the first year after surgery, between 1 and 2 years, between 2 and 3 years, between 3 and 4 years, between 4 and 5 years, and at > 5 years were 5.5, 8.8, 11.3, 17.7, 18.2, and 18.4 months, respectively. On the other hand, those in NHT patients were 1.4, 4.1, 9.1, 13.4, 27.2, and 19.3 months, respectively. The differences of PSA-DTs in the first year after surgery (p < 0.001) and between 1 and 2 years (p = 0.005) were significant between non-NHT and NHT patients.

Conclusion

Patients who received NHT had a higher risk of a rapid PSA increase when they experienced BCR, especially within 2 years after RP. In order to not miss the optimal timing of salvage treatment for BCR, intensive PSA follow-up is necessary.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10147-021-01942-8.

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.

Biomarkers for prostate cancer: prostate-specific antigen and beyond

In recent years, several new biomarkers supplementing the role of prostate-specific antigen (PSA) have become available for men with prostate cancer. Although widely used in an ad hoc manner, the role of PSA in screening asymptomatic men for prostate cancer is controversial. Several expert panels, however, have recently recommended limited PSA screening following informed consent in average-risk men, aged 55-69 years. As a screening test for prostate cancer however, PSA has limited specificity and leads to overdiagnosis which in turn results in overtreatment. To increase specificity and reduce the number of unnecessary biopsies, biomarkers such as percent free PSA, prostate health index (PHI) or the 4K score may be used, while Progensa PCA3 may be measured to reduce the number of repeat biopsies in men with a previously negative biopsy. In addition to its role in screening, PSA is also widely used in the management of patients with diagnosed prostate cancer such as in surveillance following diagnosis, monitoring response to therapy and in combination with both clinical and histological criteria in risk stratification for recurrence. For determining aggressiveness and predicting outcome, especially in low- or intermediate-risk men, tissue-based multigene tests such as Decipher, Oncotype DX (Prostate), Prolaris and ProMark, may be used. Emerging therapy predictive biomarkers include AR-V7 for predicting lack of response to specific anti-androgens (enzalutamide, abiraterone), BRAC1/2 mutations for predicting benefit from PARP inhibitor and PORTOS for predicting benefit from radiotherapy. With the increased availability of multiple biomarkers, personalised treatment for men with prostate cancer is finally on the horizon.

Long-term follow-up comparing salvage radiation therapy and androgen-deprivation therapy for biochemical recurrence after radical prostatectomy

BACKGROUND

The salvage treatments for biochemical recurrence (BCR) include local external beam radiation therapy (RT) and systemic androgen-deprivation therapy (ADT).

METHODS

We reviewed patients who underwent radical prostatectomy (RP) and developed BCR at three institutions. After excluding patients whose nadir prostate-specific antigen (PSA) was higher than 0.2 ng/mL, those who received neoadjuvant/adjuvant therapy, and those whose BCR was not treated until their PSA exceeded 4.0 ng/mL, the remaining 335 patients comprised the cohort of this study. Salvage RT and ADT were performed for 154 and 181 patients, respectively. After the failure of salvage RT, all patients received subsequent ADT. The starting point of this study was the timing of BCR and the endpoint was the development of castration-resistant prostate cancer (CRPC).

RESULTS

During the mean follow-up period of 8.5 years after BCR, CRPC was observed in 13 patients administered RT and 24 patients administered ADT. Kaplan-Meier curves demonstrated no significant difference in CRPC-free survival between the RT and ADT groups (10-year CRPC-free survival 89.9 vs. 86.3%, p = 0.199). On the other hand, we found a significant difference in CRPC-free survival between the RT and ADT groups in 50 high-risk patients with two risk factors of Grade Group ≥ 4 and PSA-doubling time  < 6 months (10-year CRPC-free survival 73.4 vs. 40.3%, p = 0.040).

CONCLUSION

This study revealed that salvage RT increases the CRPC-free survival rate compared with salvage ADT in high-risk patients with Grade Group ≥ 4 and PSA-doubling time < 6 months.

External validation of the "optimal PSA follow-up schedule after radical prostatectomy" in a new cohort

BACKGROUND

Biochemical recurrence (BCR) after radical prostatectomy (RP) is most commonly diagnosed by detecting an increase in asymptomatic prostate-specific antigen (PSA). We previously reported the "optimal PSA follow-up schedule after RP". The aim of this study was to confirm the usefulness and safety of that follow-up schedule in another cohort.

METHODS

We retrospectively reviewed the clinicopathological data of 798 consecutive patients who underwent radical prostatectomy between 2009 and 2017. We examined all PSA values measured during follow-up. Furthermore, we estimated the PSA value when we observed the "optimal PSA follow-up schedule" at each timing in the virtual follow-up. BCR was defined as an elevation of PSA to greater than 0.2 ng/ml, and the ideal PSA range for detection of BCR was regarded to be 0.2-0.4 ng/ml.

RESULTS

During the mean follow-up period of 5.8 years, BCR occurred in 115 (14.9%) patients and the frequency of virtual follow-up was significantly lower than the actual frequency. However, overlooking of BCR (detecting BCR when PSA exceeded 0.4 ng/ml) was observed in 17 patients, which is higher than the actual frequency of overlooking (12 patients). Therefore, we modified the follow-up schedule, which could achieve the lower follow-up frequency and a limited number of overlooking of BCR (7 patients).

CONCLUSION

This external validation study revealed that the "modified optimal PSA follow-up schedule after RP" can reduce the frequency of PSA measurement with a limited risk of overlooking BCR.

Relationship between PSA kinetics and Tc-99m HYNIC PSMA SPECT/CT detection rates of biochemical recurrence in patients with prostate cancer after radical prostatectomy

BACKGROUND

Prostate-specific antigen (PSA) levels should reflect or be proportional to the size and the metabolic activity of prostatic metastases. Moreover, a rapid change in PSA kinetics, either before or after treatment, is an indicator of poor prognosis after radical prostatectomy. Therefore, the purpose of this study was to investigate the effect of total PSA at the time of Tc-99m HYNIC PSMA SPECT/CT (trigger PSA), PSA velocity (PSAvel), and PSA doubling time (PSAdt) on the Tc-99m HYNIC PSMA SPECT/CT detection rate in prostate cancer patients who showed biochemical recurrence after radical prostatectomy during follow-up.

METHODS

In total, 208 patients who showed an increase in PSA were evaluable for this retrospective analysis covering November 2015 to March 2017. Data were available for calculation of PSAvel in 112 patients and for PSAdt in 157 patients. Logistic regression analysis was used to determine whether there was a relationship between the PSA levels and PSA kinetics and the rate of detection of relapse using Tc-99m HYNIC PSMA SPECT/CT.

RESULTS

Tc-99m HYNIC PSMA SPECT/CT detected disease relapse in 151 of 208 patients (72.6%). The PSA level (P < 0.0001) and PSAdt (P = 0.0036) were significantly different between SPECT-positive patients (higher PSA level, shorter PSAdt) and SPECT-negative patients (lower PSA, longer PSAdt). ROC analysis showed that a PSA level of 1.30 ng/mL and a PSAdt of 2.9 months were optimal cut-off values. Patients with purely local recurrence had lower PSAvel and longer PSAdt values (P < 0.001). According to the multivariate analysis, a pathological positive SPECT/CT scan was associated with the PSA level (P < 0.001), PSAdt <6 months (P < 0.05), and Gleason scores (GSC) >7 (P < 0.05).

CONCLUSION

The Tc-99m HYNIC PSMA SPECT/CT detection rate is influenced by trigger PSA, PSAdt, and PSAvel. Like PSA, PSAdt is an independent predictor of Tc-99m HYNIC PSMA SPECT/CT. PSAdt should be taken into account by physicians especially when PSA <1 ng/mL.

Long-term cancer control outcomes in patients with biochemical recurrence and the impact of time from radical prostatectomy to biochemical recurrence

BACKGROUND

Rates of metastatic progression (MP) and prostate cancer mortality (PCSM) are variable after biochemical recurrence (BCR) in patients who underwent radical prostatectomy (RP). To describe long-term oncological outcomes of BCR patients and to analyze risk factors for further outcomes in these men with a special focus on RP-BCR time.

METHODS

We retrospectively analyzed the data of 5509 RP patients treated between 1992 and 2006. Of those, we included 1321 patients who experienced BCR (PSA level ≥0.2 ng/mL) and did not receive any neoadjuvant or adjuvant therapy. Kaplan-Meier and time dependent Cox regression models were used.

RESULTS

Median follow-up was 121 months. MP was recorded in 177 (13.4%), PCSM in 126 (9.5%), and overall mortality (OM) in 264 (20.0%) patients. Patients with MP had worse tumor characteristics such as higher Gleason Scores (GS), rapid PSA doubling-time (DT), and shorter RP-BCR time intervals. MP-free, PCSM-free, and overall survival rates were significantly worse in patients with RP-BCR time of <12 months versus patients with 12-35.9 or ≥36 months (P ≤ 0.001). Besides higher GS and rapid PSA-DT, RP-BCR time independently predicted MP, PCSM, and OM in multivariable regression analyses. Relative to the intermediate and longest RP-BCR time interval, the shortest interval (<12) carried the highest risk for all three endpoints.

CONCLUSIONS

Only a small proportion of BCR patients proceed to MP or PCSM. Besides higher GS and rapid PSA-DT a shorter RP-BCR interval (<12 months) heralds the most aggressive phenotype for progression to all three examined endpoints: MP, PCSM, and OM.

Mortality and Androgen Deprivation Therapy as Salvage Treatment for Biochemical Recurrence after Primary Therapy for Clinically Localized Prostate Cancer

PURPOSE

Androgen deprivation therapy is often used as salvage treatment in men with rising prostate specific antigen after initial radical prostatectomy or radiotherapy for clinically localized prostate cancer. Given the lack of evidence from general practice, we examined the association of salvage androgen deprivation therapy with mortality in an observational cohort study.

MATERIALS AND METHODS

From 3 managed care organizations we assembled a retrospective cohort of all 5,804 men with newly diagnosed localized prostate cancer from 1995 to 2009 who had a prostate specific antigen increase (biochemical recurrence) after primary radical prostatectomy or radiotherapy. The main outcomes were all-cause and prostate cancer specific mortality. We used Cox proportional hazards models to estimate mortality with salvage androgen deprivation therapy as a time dependent predictor.

RESULTS

Overall salvage androgen deprivation therapy was not associated with all-cause or prostate cancer specific mortality in the prostatectomy cohort (HR 0.97, 95% CI 0.70-1.35 or HR 1.18, 95% CI 0.68-2.07) or in the radiotherapy cohort (HR 0.84, 95% CI 0.70-1.01 or HR 1.06, 95% CI 0.80-1.40, respectively). Among men with prostate specific antigen doubling time less than 9 months after the prostate specific antigen rise, salvage androgen deprivation therapy was statistically significantly associated with a decreased risk of all-cause and prostate cancer specific mortality in the prostatectomy cohort (HR 0.35, 95% CI 0.20-0.63 and HR 0.43, 95% CI 0.21-0.91) and in the radiotherapy cohort (HR 0.62, 95% CI 0.48-0.80 and HR 0.65, 95% CI 0.47-0.90, respectively).

CONCLUSIONS

We found no association of salvage androgen deprivation therapy with all-cause or cause specific mortality in most men with biochemical recurrence after primary radical prostatectomy or radiotherapy for clinically localized prostate cancer. Men with quickly progressed disease may derive a clinical benefit from salvage androgen deprivation therapy.

Determining When to Stop Prostate Specific Antigen Monitoring after Radical Prostatectomy: the Role of Ultrasensitive Prostate Specific Antigen

PURPOSE

We analyzed long-term followup data after radical prostatectomy to determine how long we should follow patients in whom the serum prostate specific antigen level measured by an ultrasensitive assay was consistently low.

MATERIALS AND METHODS

We retrospectively reviewed clinicopathological data for 582 consecutive patients who underwent open or laparoscopic radical prostatectomy between 1995 and 2004, excluding 4 patients who received adjuvant therapy. We stratified the patients according to prostate specific antigen at 3 and 5 years after surgery, and examined subsequent biochemical recurrence (elevation of prostate specific antigen to greater than 0.2 ng/ml) during followup. Mean followup was 9.7 years.

RESULTS

At 3 years after surgery prostate specific antigen levels were measured by an ultrasensitive assay in 323 patients who had not experienced biochemical recurrence. In 187 patients with undetectable prostate specific antigen levels (less than 0.01 ng/ml) the 10 and 15-year biochemical recurrence-free survival rates were 99% and 96%, respectively. At 5 years after surgery prostate specific antigen was measured in 315 patients by the ultrasensitive assay. In 162 patients with undetectable prostate specific antigen levels the 10 and 15-year biochemical recurrence-free survival rates were both 100%. In this group the prostate specific antigen level at last followup was less than 0.01 ng/ml in 132 patients, 0.01 to 0.03 ng/ml in 27 patients, and 0.06 ng/ml, 0.07 ng/ml and 0.11 ng/ml in 1 patient each.

CONCLUSIONS

This long-term review indicates that if patients have continuously undetectable prostate specific antigen levels by an ultrasensitive assay for 5 years, prostate specific antigen monitoring can be stopped with an extremely low risk of subsequent biochemical recurrence.

Use of androgen deprivation therapy as salvage treatment after primary therapy for clinically localized prostate cancer

PURPOSE

The optimal use of androgen deprivation therapy as salvage treatment (sADT) for men after initial prostatectomy or radiotherapy for clinically localized prostate cancer is undefined. We describe patterns of sADT use and investigate clinical and sociodemographic characteristics of insured men who received sADT versus surveillance in managed care settings.

METHODS

Using comprehensive electronic health records and cancer registry data from three integrated health plans, we identified all men with newly diagnosed clinically localized prostate cancer between 1995 and 2009 who received either prostatectomy (n = 16,445) or radiotherapy (n = 19,531) as their primary therapy. We defined sADT based on the timing of ADT following primary therapy and stage of cancer. We fit Cox proportional hazard models to identify sociodemographic characteristics and clinical factors associated with sADT.

RESULTS

With a median follow-up of 6 years (range 2-15 years), 13 % of men who underwent primary prostatectomy or radiotherapy received sADT. After adjusting for selected covariates, sADT was more likely to be used in men who were older (e.g., HR 1.70, 95 % CI 1.48-1.96 or HR 1.33, 95 % CI 1.17-1.52 for age 70+ relative to age 35-59 for primary prostatectomy or radiotherapy, respectively), were African-American, had a short PSA doubling time, had a higher pre-treatment risk of progression, had more comorbidities, and received adjuvant ADT for initial disease.

CONCLUSIONS

In men with localized prostate cancer in community practice initially treated with prostatectomy or radiotherapy, sADT after primary treatment was more frequent for men at greater risk of death from prostate cancer, consistent with practice guidelines.

PET/CT with (18)F-choline after radical prostatectomy in patients with PSA ≤2 ng/ml. Can PSA velocity and PSA doubling time help in patient selection?

PURPOSE

To investigate the performance of (18)F-fluorocholine ((18)F-FCH) PET/CT in relation to the prostate-specific antigen (PSA) kinetic indexes, PSA doubling time (PSAdt) and PSA velocity (PSAve), in detecting recurrent prostate cancer (PC) in a selected population of patients treated with radical prostatectomy and with PSA ≤2 ng/ml.

METHODS

The study group comprised 79 patients (mean age 70 ± 7 years, range 58 - 77 years) who had been treated with radical surgery 30 to 90 months previously and with biochemical failure (defined as a measurable serum PSA level) who were evaluated with (18)F-FCH PET/CT. In order to establish the optimal threshold for PSAdt and PSAve, the diagnostic performance of PSA, PSAdt and PSAve were compared by receiver operating characteristic analysis.

RESULTS

In the population examined, PSA (mean ± SD) was 1.37 ± 0.44 ng/ml (range 0.21 - 2 ng/ml) before PET/CT examination, PSAdt was 10.04 ± 16.67 months and PSAve was 2.75 ± 3.11 ng/ml per year. (18)F-FCH PET/CT was positive in 44 patients (55 %). PSAve and PSAdt were significantly different between patients with a positive and a negative (18)F-FCH PET/CT scan. Thresholds of 6 months for PSAdt and 1 ng/ml per year for PSAve were selected. For PSAdt ≤6 months the detection rate (DR) was 65 %, and for PSAve >1 ng/ml per year the DR was 67 %. PSA values were not significantly different between patients with a positive and a negative PET/CT scan.

CONCLUSION

The results of our study suggest that (18)F-FCH PET/CT could be considered for the evaluation of patients with biochemical recurrence of PC and with low PSA levels. Fast PSA kinetics could be useful in the selection of these patients.

Effect of curcumin on the interaction between androgen receptor and Wnt/β-catenin in LNCaP xenografts

Purpose

Curcumin is a nontoxic, chemopreventive agent possessing multifaceted functions. Our previous study showed that curcumin inhibits androgen receptor (AR) through modulation of Wnt/β-catenin signaling in LNCaP cells. Therefore, we investigated the in vivo effects of curcumin by using LNCaP xenografts.

Materials and Methods

LNCaP cells were subcutaneously inoculated in Balb/c nude mice. When the tumor volume reached greater than 100 mm³, either curcumin (500 mg/kg body weight) or vehicle was administered through oral gavage three times weekly for 4 weeks. The expression of AR and intermediate products of Wnt/β-catenin were assessed.

Results

Curcumin had an inhibitory effect on tumor growth during the early period, which was followed by a slow increase in growth over time. Tumor growth was delayed about 27% in the curcumin group. The mean prostate-specific antigen (PSA) doubling time in the curcumin group was approximately twice that in the untreated group. Curcumin significantly decreased AR expression at both the mRNA and protein level. The PSA levels tended to be reduced in the curcumin group. However, there were no significant changes in expression of Wnt/β-catenin pathway intermediates.

Conclusions

This study revealed that curcumin initially interferes with prostate cancer growth by inhibiting AR activity and possibly by reducing PSA expression. Further research is needed to investigate the plausible mechanism of the antiandrogenic action of curcumin.

Prostate-specific antigen doubling time subsequent to radical prostatectomy is a predictor of outcome following salvage external beam radiation therapy: a single-centre experience

OBJECTIVE

The aim of this study was to review the impact of salvage external beam radiotherapy (EBRT) of postprostatectomy patients with long-term follow-up on biochemical-free recurrence (BFR) and metastatic-free survival, and to describe pathological and clinical predictors of outcome.

MATERIALS AND METHODS

In the period 1987-2010, 76 postprostatectomy patients with biochemical and clinical recurrence received salvage EBRT. Patients were treated with conformal EBRT and 68 (90%) received a dose of 70 Gy; eight patients (10%) received a dose of 60-64 Gy. No patients received adjuvant or neoadjuvant androgen deprivation therapy in conjunction with salvage EBRT.

RESULTS

The median follow-up time after salvage EBRT was 82 months (range 5-192 months). Seventeen patients (22%) developed biochemical recurrence subsequent to postprostatectomy salvage EBRT during the observation time, and the overall 50 and 75 month actuarial BFR rates after salvage EBRT were 84% and 79%, respectively. Seven patients (9%) developed metastatic disease and two patients died of prostate cancer. Independent predictors of biochemical recurrence were seminal vesicle invasion (SVI) in the prostatectomy specimen (p < 0.05) and prostate-specific antigen doubling time (PSADT) of 6 months or less (p = 0.041) before salvage EBRT.

CONCLUSIONS

Salvage EBRT provides effective long-term BFR and metastatic-free survival in a selected group of patients with detectable, rising prostate-specific antigen values following radical prostatectomy. SVI and PSADT are prognostic variables for a non-durable response to salvage EBRT and thus predictors of high-risk prostate cancer in patients in whom neoadjuvant and adjuvant androgen deprivation therapy should be considered.

Impact of biochemical failure classification on clinical outcome: a secondary analysis of Radiation Therapy Oncology Group 9202 and 9413

BACKGROUND

Biochemical failure (BF) after radiation therapy is defined on the basis of a rising prostate-specific antigen (PSA) level (A1 failure) or any event that prompts the initiation of salvage androgen-deprivation therapy without PSA failure (A2). It was hypothesized that A2 failure may have a different prognosis.

METHODS

Data for 2799 eligible patients from Radiation Therapy Oncology Group (RTOG) 9202 and RTOG 9413 were analyzed. BF was defined according to the 1997 American Society for Therapeutic Radiology and Oncology consensus definition as A1 for PSA failure or as A2 for the start of salvage hormone therapy before 3 consecutive PSA rises.

RESULTS

Rates of all-cause mortality (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.5-2.0; P < .0001) and distant metastasis (DM; HR, 1.6; 95% CI, 1.3-2.0; P < .0001) were greater with A2 failure. The 5-year overall survival (OS) rates were 88.2% and 74.6% for A1 and A2, respectively (P < .0001), and the DM rates were 15.7% and 29.0%, respectively (P < .0001). The DM rate was greater at 5 years for A2 patients with DM as the first sign of failure versus patients with other A2 failures (87.3% vs 11.7%, P < .001), and this also correlated with worse OS at 5 years: 81.1% for A2 failure without DM and 52.8% with DM (P < .001). After the removal of patients with DM, the difference between A1 and A2 BF persisted for OS (P = .002) but not for DM (P = .16) CONCLUSIONS: These results suggest that patients with rising PSA levels alone have less risk than those with A2 failures; although DM was the largest contributor of adverse risk to A2 failure, it did not account for all excess risk in A2 failure.

Efficacy of tegafur-uracil (UFT) administration in castration-resistant prostate cancer patients with a history of both alternative antiandrogen therapy and estramustine phosphate sodium hydrate therapy

PURPOSE

The purpose of this study was to evaluate the efficacy of tegafur-uracil (UFT) administration as a fourth-line therapy in patients with castration-resistant prostate cancer (CRPC) who had already received combined androgen blockade (CAB) therapy (first-line), alternative antiandrogen therapy (second-line), and estramustine phosphate sodium hydrate (EMP) therapy (third-line), in order to determine who would benefit from UFT therapy.

METHODS

UFT was administered at a daily dose of 300 mg/m(2) to 26 patients, and the response to UFT 4 weeks after its induction and its toxicity were evaluated.

RESULTS

A reduction in the serum prostate-specific antigen (PSA) value was observed in 12 patients (46.2 %), while two cases (7.7 %) achieved more than 50 % reduction in PSA. Two patients (7.7 %) required discontinuation of UFT administration because of side effects (grade 2 exanthema in one patient and grade 2 nausea in one patient). A PSA response to UFT was observed, especially in patients older than 75 years and/or whose Gleason score was 8 or less.

CONCLUSIONS

Our data indicate that UFT administration as a fourth-line therapy was tolerable and effective to some degree in patients with CRPC who had already received CAB therapy, alternative antiandrogen therapy, and EMP therapy. It can be used, even in patients aged more than 75 years old, without any loss of efficacy or effect on their activities of daily life, and can be regarded as a treatment option for patients with advanced prostate cancer.

MicroRNA signature helps distinguish early from late biochemical failure in prostate cancer

PURPOSE

Prostate-specific antigen testing has led to overtreatment of prostate cancer (PCa). Only a small subset of PCa patients will have an aggressive disease that requires intensive therapy, and there is currently no biomarker to predict disease aggressiveness at the time of surgery. MicroRNAs (miRNAs) are reported to be involved in PCa pathogenesis.

METHODS

This study involved 105 participants. For the discovery phase, prostatectomy samples were dichotomized to high-risk (n = 27, biochemical failure <36 months after prostatectomy) and low-risk groups (n = 14, ≥ 36 months without biochemical failure). Expression of 754 mature miRNAs was compared between the 2 groups. Linear regression models were built to accurately predict biochemical failure risk. miRNA mimics were transfected into PCa model cell lines to test effects on proliferation and to deduce responding signaling pathways.

RESULTS

We identified 25 differentially expressed miRNAs between the biochemical failure risk groups. Based on the expression of 2-3 miRNAs, 3 logistic regression models were developed, each with a high positive predictive value. Candidate miRNAs and the best-performing model were also verified on an independent PCa set. miRNA-152, featured in the models, was further investigated by using cell line models and was shown to affect cell proliferation. Predicted interaction between miR-152 and (mRNA)ERBB3 (erythroblastic leukemia viral oncogene homolog 3) was experimentally validated in vitro.

CONCLUSIONS

miRNAs can help to predict biochemical failure risk at the time of prostatectomy.

The type of patients who would benefit from anti-androgen withdrawal therapy: could it be performed safely for aggressive prostate cancer?

This study was designed to detect the factors that were significantly associated with the results of anti-androgen withdrawal (AAWD) therapy, and to examine whether patients with aggressive prostate cancer demonstrating a short prostate-specific antigen (PSA)-doubling time (DT) could benefit from it without even greater exacerbation of the disease. We conducted a retrospective chart review study of 121 patients who received AAWD therapy due to failed combined androgen blockade (CAB) therapy. A reduction in the serum PSA level after AAWD was observed in 35 patients (28.9 %), and a greater than 50 % decrease from the baseline serum PSA level was observed in 16 patients (13.2 %). Shortening of PSA-DT after AAWD was observed in 48 patients (39.7 %). Univariate and multivariate analyses demonstrated that only a long duration of prior anti-androgen treatment was selected as a significant predictor for a good response to AAWD therapy. With respect to exacerbation after AAWD, we found that patients with a short baseline PSA-DT conversely had a low risk of subsequent shortening of PSA-DT. Using these two factors, we could stratify the patients into four groups, and patients with prior duration of anti-androgen >18 months and PSA-DT ≤3 months demonstrated the best results with a good response rate (67.9 %) and a low risk for a worsening of the disease (14.3 %). We conclude that AAWD would be effective especially for patients whose cancer progressed rapidly (short PSA-DT) after a long stable period under CAB and should be recommended before embarking on the next therapeutic maneuver.

Risk Stratification after Biochemical Failure following Curative Treatment of Locally Advanced Prostate Cancer: Data from the TROG 96.01 Trial

Purpose. Survival following biochemical failure is highly variable. Using a randomized trial dataset, we sought to define a risk stratification scheme in men with locally advanced prostate cancer (LAPC). Methods. The TROG 96.01 trial randomized 802 men with LAPC to radiation ± neoadjuvant androgen suppression therapy (AST) between 1996 and 2000. Ten-year follow-up data was used to develop three-tier post-biochemical failure risk stratification schemes based on cutpoints of time to biochemical failure (TTBF) and PSA doubling time (PSADT). Schemes were evaluated in univariable, competing risk models for prostate cancer-specific mortality. The performance was assessed by c-indices and internally validated by the simple bootstrap method. Performance rankings were compared in sensitivity analyses using multivariable models and variations in PSADT calculation. Results. 485 men developed biochemical failure. c-indices ranged between 0.630 and 0.730. The most discriminatory scheme had a high risk category defined by PSADT < 4 months or TTBF < 1 year and low risk category by PSADT > 9 months or TTBF > 3 years. Conclusion. TTBF and PSADT can be combined to define risk stratification schemes after biochemical failure in men with LAPC treated with short-term AST and radiotherapy. External validation, particularly in long-term AST and radiotherapy datasets, is necessary.

Impact of total PSA, PSA doubling time and PSA velocity on detection rates of 11C-Choline positron emission tomography in recurrent prostate cancer

PURPOSE

To evaluate the effect of total PSA (tPSA) and PSA kinetics on the detection rates of (11)C-Choline PET in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) or external beam radiotherapy (EBRT).

METHODS

We included 185 patients with BCR after RP (PSA >0.2 ng/ml) or after EBRT (ASTRO definition). After injection of 400 MBq 11C-Choline i.v., a scan was made using the ECAT HR + PET camera with CT fusion images or Siemens mCT PET/CT. Biopsy-proven histology, confirmative imaging (CT or bone scan) and/or clinical follow-up (PSA) were used as composite reference. Statistical analysis was performed using PASW Statistics 18.

RESULTS

11C-Choline PET was positive in 124/185 cases (65%) (in 22/61 (36%) after RP, 102/124 (82%) after EBRT). In 79 patients a local recurrence was identified, and 45 patients showed locoregional metastases on PET/CT. In 20 cases a proven false-negative PET scan was observed. Positive PET scans were confirmed by histology in 87/124 (70%) cases, by confirmatory imaging in 34/124 (28%) and by clinical follow-up after salvage treatment in 3 (2%) cases. The ROC analysis to detect a recurrence showed significant difference in area under the curve (AUC) of tPSA 0.721(p < 0.001) and PSA velocity 0.730 (p < 0.001). PSA doubling time showed no significant difference with an AUC of 0.542 (p = 0.354). Detection rates are <50% in tPSA <2 ng/ml and/or PSA velocity <1 ng/ml/year.

CONCLUSIONS

Total serum PSA and PSA velocity have significant effect on the detection rates of 11C-Choline PET/CT in men with a BCR after RP or EBRT.

PSA nadir of <0.5 ng/mL following brachytherapy for early-stage prostate adenocarcinoma is associated with freedom from prostate-specific antigen failure

PURPOSE

Because limited information exists regarding whether the rate or magnitude of PSA decline following brachytherapy predicts long-term clinical outcomes, we evaluated whether achieving a prostate-specific antigen (PSA) nadir (nPSA) <0.5 ng/mL following brachytherapy is associated with decreased PSA failure and/or distant metastasis.

METHODS AND MATERIALS

We retrospectively analyzed our database of early-stage prostate adenocarcinoma patients who underwent brachytherapy, excluding those receiving androgen-deprivation therapy and those with <2 years follow-up. Median and mean pretreatment PSA were 6 ng/mL and 7.16 ng/mL, respectively. By clinical stage, 775 were low risk (≤ T2a), 126 were intermediate risk (T2b), and 20 were high risk (>T2b). By Gleason score, 840 were low risk (≤ 6), 71 were intermediate risk (7), and 10 were high risk (>7). Patients were treated with brachytherapy only (I-125, n = 779, or Pd-103, n = 47), or brachytherapy + external-beam radiation therapy (n = 95). Median follow-up was 6.3 years. We noted whether nPSA <0.5 ng/mL was achieved and the time to achieve this nadir and tested for associations with pretreatment risk factors. We also determined whether this PSA endpoint was associated with decreased PSA failure or distant metastasis.

RESULTS

Absence of high-risk factors in clinical stage (≤ T2b), Gleason score (≤ 7), and pretreatment PSA (≤ 20 ng/mL) was significantly associated with achieving nPSA <0.5 ng/mL. By Kaplan-Meier analysis, patients achieving nPSA <0.5 ng/mL had significantly higher long-term freedom from biochemical failure (FFBF) than nonresponders (5-year FFBF: 95.2 ± 0.8% vs. 71.5 ± 6.7%; p < 0.0005). Among responders, those who achieved nPSA <0.5 ng/mL in ≤ 5 years had higher FFBF than those requiring >5 years (5-year FFBF: 96.7 ± 0.7% vs. 80.8 ± 4.6%; p < 0.0005). On multivariate analysis, patients who achieved nPSA <0.5 ng/mL in ≤ 5 years had significantly higher FFBF than other patients.

CONCLUSIONS

Pretreatment risk factors (clinical tumor stage, Gleason score, pretreatment PSA) strongly predict for patients achieving nPSA <0.5 ng/mL following brachytherapy, and this cohort had significantly higher long-term FFBF.

Role of MRI in follow-up after focal therapy for prostate carcinoma

OBJECTIVE

In patients with clinically suspected local recurrence of prostate cancer, a lobulated hyperintense mass in the radical prostatectomy fossa can be readily visualized with T2-weighted MRI, but this imaging technique is less successful after treatments such as radiation therapy, high-intensity focused ultrasound, and cryosurgery. We describe the additional value of functional techniques in the assessment of local recurrence.

CONCLUSION

The use of functional MRI techniques such as MR spectroscopy, diffusion-weighted imaging, and dynamic contrast-enhanced MRI has shown promise in increasing overall imaging performance in the detection of local recurrence.

Influence of trigger PSA and PSA kinetics on 11C-Choline PET/CT detection rate in patients with biochemical relapse after radical prostatectomy

The purpose of this study was to investigate the effect of total prostate-specific antigen (PSA) at the time of (11)C-choline PET/CT (trigger PSA), PSA velocity (PSAvel), and PSA doubling time (PSAdt) on (11)C-choline PET/CT detection rate in patients treated with radical prostatectomy for prostate cancer, who showed biochemical failure during follow-up.

METHODS

A total of 190 patients treated with radical prostatectomy for prostate cancer who showed an increase in PSA (mean, 4.2; median, 2.1; range, 0.2-25.4 ng/mL) were retrospectively enrolled. All patients were studied with (11)C-choline PET/CT. Patients were grouped according to trigger PSA (PSA </= 1 ng/mL, 1 < PSA </= 2 ng/mL, 2 < PSA </= 5 ng/mL, and PSA > 5 ng/mL). In 106 patients, data were available for calculation of PSAvel and PSAdt. Logistic regression analysis was used to determine whether there was a relationship between PSA levels and PSA kinetics and the rate of detection of relapse using PET.

RESULTS

(11)C-choline PET/CT detected disease relapse in 74 of 190 patients (38.9%). The detection rate of (11)C-choline PET/CT was 19%, 25%, 41%, and 67% in the 4 subgroups-PSA </= 1 ng/mL (51 patients), 1 < PSA </= 2 ng/mL (39 patients), 2 < PSA </= 5 ng/mL (51 patients), and PSA > 5 ng/mL (49 patients)-respectively. Trigger PSA values were statistically different between PET-positive patients (median PSA, 4.0 ng/mL) and PET-negative patients (median PSA, 1.4 ng/mL) (P = 0.0001). Receiver-operating-characteristic analysis showed an optimal cutoff point for trigger PSA of 2.43 ng/mL (area under the curve, 0.76). In 106 patients, PSAdt and PSAvel values were statistically different between patients with PET-positive and -negative scan findings (P = 0.04 and P = 0.03). The (11)C-choline PET/CT detection rate was 12%, 34%, 42%, and 70%, respectively, in patients with PSAvel < 1 ng/mL/y (33 patients), 1 < PSAvel </= 2 ng/mL/y (26 patients), 2 < PSAvel </= 5 ng/mL/y (19 patients), and PSAvel > 5 ng/mL/y (28 patients). The (11)C-choline PET/CT detection rate was 20%, 40%, 48%, and 60%, respectively, in patients with PSAdt > 6 mo (45 patients), 4 < PSAdt </= 6 mo (20 patients), 2 < PSAdt </= 4 mo (31 patients), and PSAdt </= 2 mo (10 patients). There was no statistical difference between PET-positive and -negative scan detection rates according to the Gleason score, pT and N status, patient age, or duration between surgery and biochemical relapse. Trigger PSA and PSAvel were found to be independent predictive factors for a PET-positive result (P = 0.002; P = 0.04) and PSAdt was found to be an independent factor only in patients with trigger PSA less than 2 ng/mL (P = 0.05) using multivariate analysis.

CONCLUSION

The (11)C-choline PET/CT detection rate is influenced by trigger PSA, PSAdt, and PSAvel. This finding could be used to improve the selection of patients for scanning by reducing the number of false-negative scans and increasing the detection rate of disease in patients with early relapse and potentially curative disease.

Clinical significance and treatment of biochemical recurrence after definitive therapy for localized prostate cancer

PURPOSE

Radical prostatectomy and external beam radiation therapy are the established and definitive interventions for clinically localized prostate cancer. These treatment modalities are yet subject to failure observed first by biochemical recurrence, defined by increases in the serum PSA level. We investigated the significance of biochemical recurrence after definitive therapy and the available salvage therapy options for cancer recurrence.

METHODS

A literature search was performed in PubMed, and applicable studies addressing biochemical recurrence and salvage options after radical prostatectomy or external beam radiation therapy were reviewed.

RESULTS

After radical prostatectomy, a detectable serum PSA level indicates biochemical recurrence. Whether to administer salvage therapy locally or systemically depends largely on prognostic factors including PSA doubling time, Gleason's score, pathologic stage, and the time interval between radical prostatectomy and biochemical recurrence. Early initiation of salvage therapy has been shown to significantly impact on cancer outcomes. After external beam radiation therapy, no single PSA level can define biochemical recurrence. Instead, it has been defined by increases in the PSA level above the nadir. Following radiation therapy, PSA doubling time and Gleason score play important roles in determining the need for local versus systemic salvage therapy.

CONCLUSIONS

After the diagnosis of biochemical recurrence, it is critical to perform a timely clinical assessment using the prognostic factors mentioned above. Prompt initiation of salvage therapy may prevent subsequent clinical progression and prostate cancer-specific mortality.

Prostate cancer-specific survival following salvage radiotherapy vs observation in men with biochemical recurrence after radical prostatectomy

CONTEXT

Biochemical disease recurrence after radical prostatectomy often prompts salvage radiotherapy, but no studies to date have had sufficient numbers of patients or follow-up to determine whether radiotherapy improves survival, and if so, the subgroup of men most likely to benefit.

OBJECTIVES

To quantify the relative improvement in prostate cancer-specific survival of salvage radiotherapy vs no therapy after biochemical recurrence following prostatectomy, and to identify subgroups for whom salvage treatment is most beneficial.

DESIGN, SETTING, AND PATIENTS

Retrospective analysis of a cohort of 635 US men undergoing prostatectomy from 1982-2004, followed up through December 28, 2007, who experienced biochemical and/or local recurrence and received no salvage treatment (n = 397), salvage radiotherapy alone (n = 160), or salvage radiotherapy combined with hormonal therapy (n = 78).

MAIN OUTCOME MEASURE

Prostate cancer-specific survival defined from time of recurrence until death from disease.

RESULTS

With a median follow-up of 6 years after recurrence and 9 years after prostatectomy, 116 men (18%) died from prostate cancer, including 89 (22%) who received no salvage treatment, 18 (11%) who received salvage radiotherapy alone, and 9 (12%) who received salvage radiotherapy and hormonal therapy. Salvage radiotherapy alone was associated with a significant 3-fold increase in prostate cancer-specific survival relative to those who received no salvage treatment (hazard ratio [HR], 0.32 [95% confidence interval {CI}, 0.19-0.54]; P<.001). Addition of hormonal therapy to salvage radiotherapy was not associated with any additional increase in prostate cancer-specific survival (HR, 0.34 [95% CI, 0.17-0.69]; P = .003). The increase in prostate cancer-specific survival associated with salvage radiotherapy was limited to men with a prostate-specific antigen doubling time of less than 6 months and remained after adjustment for pathological stage and other established prognostic factors. Salvage radiotherapy initiated more than 2 years after recurrence provided no significant increase in prostate cancer-specific survival. Men whose prostate-specific antigen level never became undetectable after salvage radiotherapy did not experience a significant increase in prostate cancer-specific survival. Salvage radiotherapy also was associated with a significant increase in overall survival.

CONCLUSIONS

Salvage radiotherapy administered within 2 years of biochemical recurrence was associated with a significant increase in prostate cancer-specific survival among men with a prostate-specific antigen doubling time of less than 6 months, independent of other prognostic features such as pathological stage or Gleason score. These preliminary findings should be validated in other settings, and ultimately, in a randomized controlled trial.

Prostate cancer

In developed countries, prostate cancer is the second most frequently diagnosed cancer, and the third most common cause of death from cancer in men. Apart from age and ethnic origin, a positive family history is probably the strongest known risk factor. Clinically, prostate cancer is diagnosed as local or advanced, and treatments range from surveillance to radical local treatment or androgen-deprivation treatment. Androgen deprivation reduces symptoms in about 70-80% of patients with advanced prostate cancer, but most tumours relapse within 2 years to an incurable androgen-independent state. The recorded incidence of prostate cancer has substantially increased in the past two decades, probably because of the introduction of screening with prostate-specific antigen, the use of improved biopsy techniques for diagnosis, and increased public awareness. Trends in mortality from the disease are less clearcut. Mortality changes are not of the same magnitude as the changes in incidence, and in some countries mortality has been stable or even decreased. The disparity between reported incidence and mortality rates leads to the probable conclusion that only a small proportion of diagnosed low-risk prostate cancers will progress to life-threatening disease during the lifetime of the patient.

Advantages of prostate-specific antigen (PSA) clearance model over simple PSA half-life computation to describe PSA decrease after prostate adenomectomy

OBJECTIVES

A population kinetic approach based on PSA clearance (CL(PSA)) may be a more rational strategy to characterize prostate-specific antigen (PSA) decrease profile after prostate surgery than the commonly used method (half-life from mono/bi-exponential models).

METHODS

We used 182 post-adenomectomy PSA concentrations from 56 benign prostatic hyperplasia patients to build, with NONMEM software, a multi-exponential and a CL(PSA) model for comparison.

RESULTS

The best multi-exponential model was PSA(t)=4.96e(-)(0.269t)+3.10e(-)(0.16t)+0.746e(+)(0.0002t) with a stable median residual PSA at 0.64 ng/mL. The best model parametrized with clearance was CL(PSA)=0.0229()(AGE/69)(3.78). Akaike information criteria and standard errors favored the CL(PSA) model. Median peripheral zone and transitional zone productions were 0.034 ng/mL/cm(3) and 0.136 ng/mL/g. A threshold at 2 ng/mL on day 90 allowed for a diagnostic of biochemical relapse diagnostic.

CONCLUSIONS

The population CL(PSA) model was superior to the multi-exponential approach for investigating individual post-adenomectomy PSA decreases.