Rate of PSA rise predicts metastatic versus local recurrence after definitive radiotherapy

Plasma metabolomics profiling of 580 patients from an Early Detection Research Network prostate cancer cohort

Prostate cancer is the second most common cancer in men and affects 1 in 9 men in the United States. Early screening for prostate cancer often involves monitoring levels of prostate-specific antigen (PSA) and performing digital rectal exams. However, a prostate biopsy is always required for definitive cancer diagnosis. The Early Detection Research Network (EDRN) is a consortium within the National Cancer Institute aimed at improving screening approaches and early detection of cancers. As part of this effort, the Weill Cornell EDRN Prostate Cancer has collected and biobanked specimens from men undergoing a prostate biopsy between 2008 and 2017. In this report, we describe blood metabolomics measurements for a subset of this population. The dataset includes detailed clinical and prospective records for 580 patients who underwent prostate biopsy, 287 of which were subsequentially diagnosed with prostate cancer, combined with profiling of 1,482 metabolites from plasma samples collected at the time of biopsy. We expect this dataset to provide a valuable resource for scientists investigating prostate cancer metabolism.

MRI-guided focal or integrated boost high dose rate brachytherapy for recurrent prostate cancer

Background and purpose

Locally recurrent prostate cancer after radiotherapy merits an effective salvage strategy that mitigates the risk of adverse events. We report outcomes of a cohort enrolled across two institutions investigating MRI-guided tumor-targeted salvage high dose rate brachytherapy (HDR-BT).

Materials and methods

Analysis of a prospective cohort of 88 patients treated across two institutions with MRI-guided salvage HDR-BT to visible local recurrence after radiotherapy (RT). Tumor target dose ranged from 22-26 Gy, using either an integrated boost (ibBT) or focal technique (fBT), delivered in two implants over a median of 7 days. Outcome metrics included cancer control and toxicity (CTCAE). Quality of life (QoL-EPIC) was analyzed in a subset.

Results

At a median follow-up of 35 months (6 -134), 3 and 5-year failure-free survival (FFS) outcomes were 67% and 49%, respectively. At 5 years, fBT was associated with a 17% cumulative incidence of local failure (LF) outside the GTV (vs. 7.8% ibBT, p=0.14), while LF within the GTV occurred in 13% (vs. 16% ibBT, p=0.81). Predictors of LF outside fBT volumes included pre-salvage PSA>7 ng/mL (p=0.03) and interval since RT less than 5 years (p=0.04). No attributable grade 3 events occurred, and ibBT was associated with a higher rate of grade 2 toxicity (p<0.001), and trend towards a larger reduction in QoL sexual domain score (p=0.07), compared to fBT.

Conclusion

A tumor-targeted HDR-BT salvage approach achieved favorable cancer control outcomes. While a fBT was associated with less toxicity, it may be best suited to a subgroup with lower PSA at later recurrence. Tumor targeted dose escalation may be warranted.

Association between prostate-specific antigen change over time and prostate cancer recurrence risk: A joint model

Background

Prostate specific antigen (PSA) is an important biomarker to monitor patients after treated with radiation therapy (RT). The aim of this study is to evaluate the relationship between the PSA data and prostate cancer recurrence using the joint modeling.

Methods

This historical cohort study was performed on 422 prostate cancer patients. Inclusion criteria included: patients with localized prostate cancer referring to Cancer Institute in Tehran (Iran) from 2007 to 2012, and under radiation therapy. Joint model has two components or sub-models. We showed the results by parameter estimating the longitudinal sub-model and survival sub-model. EM algorithm, Newton-Gauss and Gauss-Hermit law were used for final model parameters. R software version 3.2 was used for statistical analysis.

Results

In this study, considering the inclusion and exclusion criteria, out of 422 patients, the data on 314 cases were selected for analysis and the main result of joint model was obtained. PSA directly and significantly was associated with recurrence risk, therefore increasing 2.6 ml/lit PSA (one unit in transformed PSA) increases 39% recurrence risk (95% CI for RR: 1.09-1.77). Also, slope of PSA trend has significant association with prostate cancer recurrence risk (95% CI for RR: 1.05-1.41).

Conclusion

This study showed a significant relationship between PSA, and its slope with the recurrence risk by joint model, with regard to the pathological, demographic and clinical features in the Iranian population.

Methods for the evaluation of biomarkers in patients with kidney and liver diseases: multicentre research programme including ELUCIDATE RCT

Background

Protein biomarkers with associations with the activity and outcomes of diseases are being identified by modern proteomic technologies. They may be simple, accessible, cheap and safe tests that can inform diagnosis, prognosis, treatment selection, monitoring of disease activity and therapy and may substitute for complex, invasive and expensive tests. However, their potential is not yet being realised.

Design and methods

The study consisted of three workstreams to create a framework for research: workstream 1, methodology – to define current practice and explore methodology innovations for biomarkers for monitoring disease; workstream 2, clinical translation – to create a framework of research practice, high-quality samples and related clinical data to evaluate the validity and clinical utility of protein biomarkers; and workstream 3, the ELF to Uncover Cirrhosis as an Indication for Diagnosis and Action for Treatable Event (ELUCIDATE) randomised controlled trial (RCT) – an exemplar RCT of an established test, the ADVIA Centaur® Enhanced Liver Fibrosis (ELF) test (Siemens Healthcare Diagnostics Ltd, Camberley, UK) [consisting of a panel of three markers – (1) serum hyaluronic acid, (2) amino-terminal propeptide of type III procollagen and (3) tissue inhibitor of metalloproteinase 1], for liver cirrhosis to determine its impact on diagnostic timing and the management of cirrhosis and the process of care and improving outcomes.

Results

The methodology workstream evaluated the quality of recommendations for using prostate-specific antigen to monitor patients, systematically reviewed RCTs of monitoring strategies and reviewed the monitoring biomarker literature and how monitoring can have an impact on outcomes. Simulation studies were conducted to evaluate monitoring and improve the merits of health care. The monitoring biomarker literature is modest and robust conclusions are infrequent. We recommend improvements in research practice. Patients strongly endorsed the need for robust and conclusive research in this area. The clinical translation workstream focused on analytical and clinical validity. Cohorts were established for renal cell carcinoma (RCC) and renal transplantation (RT), with samples and patient data from multiple centres, as a rapid-access resource to evaluate the validity of biomarkers. Candidate biomarkers for RCC and RT were identified from the literature and their quality was evaluated and selected biomarkers were prioritised. The duration of follow-up was a limitation but biomarkers were identified that may be taken forward for clinical utility. In the third workstream, the ELUCIDATE trial registered 1303 patients and randomised 878 patients out of a target of 1000. The trial started late and recruited slowly initially but ultimately recruited with good statistical power to answer the key questions. ELF monitoring altered the patient process of care and may show benefits from the early introduction of interventions with further follow-up. The ELUCIDATE trial was an ‘exemplar’ trial that has demonstrated the challenges of evaluating biomarker strategies in ‘end-to-end’ RCTs and will inform future study designs.

Conclusions

The limitations in the programme were principally that, during the collection and curation of the cohorts of patients with RCC and RT, the pace of discovery of new biomarkers in commercial and non-commercial research was slower than anticipated and so conclusive evaluations using the cohorts are few; however, access to the cohorts will be sustained for future new biomarkers. The ELUCIDATE trial was slow to start and recruit to, with a late surge of recruitment, and so final conclusions about the impact of the ELF test on long-term outcomes await further follow-up. The findings from the three workstreams were used to synthesise a strategy and framework for future biomarker evaluations incorporating innovations in study design, health economics and health informatics.

Trial registration

Current Controlled Trials ISRCTN74815110, UKCRN ID 9954 and UKCRN ID 11930.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 6, No. 3. See the NIHR Journals Library website for further project information.

Image-Guided Robotic Radiosurgery as Salvage Therapy for Locally Recurrent Prostate Cancer after External Beam Irradiation: Retrospective Feasibility Study on Six Cases

Aims and background

Technological advances in treatment planning and execution are providing new potential opportunities in the treatment of recurrent prostate cancer. This study was conducted to evaluate the feasibility and safety of reirradiation with image-guided radiosurgery using CyberKnife, a robotic arm-driven compact linear accelerator, for intraprostatic recurrence after external beam radiotherapy (EBRT).

Methods

Between September 2007 and May 2008, 6 patients diagnosed with locally recurrent prostate cancer after EBRT were treated using the CyberKnife system. The total reirradiation dose was 30 Gy in five fractions. Prior to radiosurgery four patients were treated with androgen-deprivation therapy. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and the Houston-Phoenix definition (PSA nadir + 2 ng/mL) were used for toxicity and biochemical failure evaluation, respectively.

Results

After a median follow-up of 11.2 months (range, 9.6–18.6 months), all patients are alive with no evidence of severe urinary or rectal acute morbidity. Local control cannot be exactly determined due to the short follow-up and the bias of the use of androgen ablation. Four patients had biochemical failure, three of them with clinical failure evidence (lymph node, bone and lung metastasis, respectively): none of these patients had clinical evidence of tumor persistence in the prostate.

Conclusions

Salvage radiosurgery with CyberKnife after irradiation is feasible with low urinary and rectal morbidity. A longer follow-up and a larger number of patients are necessary to evaluate its effectiveness and optimal patient selection criteria.

Multiparametric Magnetic Resonance Imaging of Recurrent Prostate Cancer

There is growing consensus that multiparametric magnetic resonance imaging (mpMRI) is an effective modality in the detection of locally recurrent prostate cancer after prostatectomy and radiation therapy. The emergence of magnetic resonance (MR)-guided focal therapies, such as cryoablation, high-intensity focused ultrasound, and laser ablation, have made the use of mpMRI even more important, as the normal anatomy is inevitably altered and the detection of recurrence is made more difficult. The aim of this article is to review the utility of mpMRI in detecting recurrent prostate cancer in patients following radical prostatectomy, radiation therapy, and focal therapy and to discuss expected post-treatment mpMRI findings, the varied appearance of recurrent tumors, and their mimics.

Current Status of Salvage Cryoablation for Prostate Cancer following Radiation Failure

The role of salvage cryoablation of the prostate for patients with clinically localized prostate cancer that have failed radiotherapy to the prostate is reviewed with reference to alternatives including salvage radical prostatectomy and brachytherapy. The diagnosis and work-up of local recurrence/persistence of cancer in the prostate are reviewed and the patient selection criteria for salvage cryoablation is discussed. Technical aspects of the cryoablation procedure along with the outcome in terms of cancer control and treatment-related complications are detailed. The five-year biochemical disease-free rate is approximately 40%. The complication rate is acceptable. Salvage cryoablation definitely has a role in the management of localized prostate cancer treatment failure following radiotherapy, especially in older patients and those with some comorbidities.

Decision-making Processes among Prostate Cancer Survivors with Rising PSA Levels: Results from a Qualitative Analysis

BACKGROUND

Prostate cancer survivors with a rising prostate-specific antigen (PSA) level have few treatment options, experience a heightened state of uncertainty about their disease trajectory that might include the possibility of cancer metastasis and death, and often experience elevated levels of distress as they have to deal with a disease they thought they had conquered. Guided by self-regulation theory, the present study examined the cognitive and affective processes involved in shared decision making between physicians and patients who experience a rising PSA after definitive treatment for prostate cancer.

METHODS

In-depth interviews were conducted with 34 prostate cancer survivors who had been diagnosed with a rising PSA (i.e., biochemical failure) within the past 12 months. Survivors were asked about their experiences and affective responses after being diagnosed with a rising PSA and while weighing potential treatment options. In addition, patients were asked about their decision-making process for the initial prostate cancer treatment.

RESULTS

Compared with the initial diagnosis, survivors with a rising PSA reported increased negative affect following their diagnosis, concern about the treatability of their disease, increased planning and health behavior change, heightened levels of worry preceding doctor appointments (especially prior to the discussion of PSA testing results), and a strong reliance on physicians' treatment recommendations.

CONCLUSIONS

Prostate cancer survivors' decision-making processes for the treatment of a rising PSA are markedly different from those of the initial diagnosis of prostate cancer. Because patients experience heightened distress and rely more heavily on their physicians' recommendations with a rising PSA, interactions with the health care provider provide an excellent opportunity to address and assist patients with managing the uncertainty and distress inherent with rising PSA levels.

Retreatment for prostate cancer with stereotactic body radiation therapy (SBRT): Feasible or foolhardy?

The most popular therapeutic option in the management of radio-recurrent prostatic carcinoma is represented by the androgen deprivation therapy, that however should be considered only palliative and hampered by potential adverse effects of testosterone suppression. Local therapies such as surgery, cryoablation or brachytherapy might be curative choices for patients in good conditions and with a long-life expectancy, but at cost of significant risk of failure and severe toxicity. The administration of stereotactic body radiation therapy (SBRT) in this setting have come about because of tremendous technologic advances in image guidance and treatment delivery techniques that enable the delivery of large doses to tumor with reduced margins and high gradients outside the target, thereby reducing the volume of rectum which already received significant doses from primary radiotherapy. So far, very modest data are available to support its employment. Rationale, clinical experience, and challenges are herein reviewed and discussed.

Comparison of biochemical failure rates between permanent prostate brachytherapy and radical retropubic prostatectomy as a function of posttherapy PSA nadir plus 'X'

Background

Prostate-specific antigen (PSA) nadir + 2 ng/mL, also known as the Phoenix definition, is the definition most commonly used to establish biochemical failure (BF) after external beam radiotherapy for prostate cancer management. The purpose of this study is to compare BF rates between permanent prostate brachytherapy (PPB) and radical retropubic prostatectomy (RRP) as a function of PSA nadir plus varying values of X and examine the associated implications.

Methods and materials

We retrospectively searched for patients who underwent PPB or RRP at our institution between 1998 and 2004. Only primary patients not receiving androgen-deprivation therapy were included in the study. Three RRP patients were matched to each PPB patient on the basis of prognostic factors. BF rates were estimated for PSA nadirs + different values of X.

Results

A total of 1,164 patients were used for analysis: 873 in the RRP group and 291 in the PPB group. Patients were equally matched by clinical stage, biopsy Gleason sum, primary Gleason grade, and pretherapy PSA value. Median follow-up was 3.1 years for RRP patients and 3.6 years in the PPB group (P = .01). Using PSA nadir + 0.1 ng/mL for the definition of BF, the 5-year BF rate was 16.3% for PPB patients and 13.5% for RRP patients (P = .007), whereas at nadir + 2 ng/mL or greater, the BF rates were less than 3% and were indistinguishable between PPB and RRP patients.

Conclusions

In a cohort of well-matched patients who had prostatectomy or brachytherapy, we examined BF as a function of nadir + X, where X was treated as a continuous variable. As X increases from 0.1 to 2.0 ng/mL, the BF curves converge, and above 2.0 ng/mL they are essentially indistinguishable. The data presented are of interest as BF definitions continue to evolve.

Multi-Parametric MRI-Directed Focal Salvage Permanent Interstitial Brachytherapy for Locally Recurrent Adenocarcinoma of the Prostate: A Novel Approach

Even with the technological advances of dose-escalated IMRT with the addition of the latest image guidance technologies, local failures still occur. The combination of MRI-based imaging techniques can yield quantitative information that reflects on the biological properties of prostatic tissues. These techniques provide unique information that can be used for tumor detection in the treated gland. With the advent of these improved imaging modalities, it has become possible to more effectively image local recurrences within the prostate gland. With better imaging, these focal recurrences can be differentially targeted with salvage brachytherapy minimizing rectal and bladder toxicity. Here we report a novel use of MRI-directed focal brachytherapy after local recurrence. This technique offers a unique opportunity to safely and successfully treat recurrent prostate cancer, previously treated with definitive radiation therapy. The use of multi-parametric MRI-directed focal salvage permanent interstitial brachytherapy for locally recurrent adenocarcinoma of the prostate is a promising strategy to avoid more aggressive and expensive treatments that are associated with increased morbidity, potentially improving survival at potentially lower costs.

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.

Early salvage hormonal therapy for biochemical failure improved survival in prostate cancer patients after neoadjuvant hormonal therapy plus radiation therapy--a secondary analysis of irish clinical oncology research group 97-01

PURPOSE

To assess the survival benefit of early vs late salvage hormonal therapy (HT), we performed a secondary analysis on patients who developed recurrence from Irish Clinical Oncology Research Group 97-01, a randomized trial comparing 4 vs 8 months neoadjuvant HT plus radiation therapy (RT) in intermediate- and high-risk prostate adenocarcinoma.

METHODS AND MATERIALS

A total of 102 patients from the trial who recurred were analyzed at a median follow-up of 8.5 years. The patients were divided into 3 groups based on the timing of salvage HT: 57 patients had prostate-specific antigen (PSA)≤10 ng/mL and absent distant metastases (group 1, early), 21 patients had PSA>10 ng/mL and absent distant metastases (group 2, late), and 24 patients had distant metastases (group 3, late). The endpoint analyzed was overall survival (OS) calculated from 2 different time points: date of enrolment in the trial (OS1) and date of initiation of salvage HT (OS2). Survival was estimated using Kaplan-Meier curves and a Cox regression model.

RESULTS

The OS1 differed significantly between groups (P<.0005): OS1 at 10 years was 78% in group 1, 42% in group 2, and 29% in group 3. The OS2 also differed significantly between groups (P<.0005): OS2 at 6 years was 70% in group 1, 47% in group 2, and 22% in group 3. Group 1 had the longest median time from end of RT to biochemical failure compared with groups 2 and 3 (3.3, 0.9, and 1.7 years, respectively; P<.0005). Group 1 also had the longest median PSA doubling time compared with groups 2 and 3 (9.9, 3.6, and 2.4 months, respectively; P<.0005). On multivariate analysis, timing of salvage HT, time from end of RT to biochemical failure, and PSA nadir on salvage HT were significant predictors of survival.

CONCLUSION

Early salvage HT based on PSA≤10 ng/mL and absent distant metastases improved survival in patients with prostate cancer after failure of initial treatment with neoadjuvant HT plus RT.

MR imaging of treated prostate cancer

Many management options are available to patients with newly diagnosed prostate cancer. Magnetic resonance (MR) imaging plays an important role in initial staging of prostate cancer, but it also aids in tumor detection when there is clinical or biochemical suspicion of residual or recurrent disease after treatment. The purpose of this review is to describe the normal appearances of the prostatic region after different kinds of treatment for prostate cancer and to discuss how these appearances differ from those of recurrent and residual disease. Several MR imaging techniques used in evaluating patients with prostate cancer are described, including conventional MR imaging sequences (mainly T1- and T2-weighted sequences), MR spectroscopic imaging, diffusion-weighted imaging, and dynamic contrast agent-enhanced MR imaging. Clinical considerations, together with the different approaches for interpreting serum prostate-specific antigen values in the posttreatment setting, are also presented. All forms of treatment alter the MR imaging features of the prostatic region to a greater or lesser extent, and it is important to be able to recognize expected posttreatment appearances and distinguish them from the features of recurrent or residual cancer to aid subsequent clinical management.

Semiparametric Stochastic Modeling of the Rate Function in Longitudinal Studies

In longitudinal biomedical studies, there is often interest in the rate functions, which describe the functional rates of change of biomarker profiles. This paper proposes a semiparametric approach to model these functions as the realizations of stochastic processes defined by stochastic differential equations. These processes are dependent on the covariates of interest and vary around a specified parametric function. An efficient Markov chain Monte Carlo algorithm is developed for inference. The proposed method is compared with several existing methods in terms of goodness-of-fit and more importantly the ability to forecast future functional data in a simulation study. The proposed methodology is applied to prostate-specific antigen profiles for illustration. Supplementary materials for this paper are available online.

Disease and host characteristics as predictors of time to first bone metastasis and death in men with progressive castration-resistant nonmetastatic prostate cancer

BACKGROUND

The natural history of castration-resistant nonmetastatic prostate cancer is poorly defined.

METHODS

The authors used data from 331 subjects in the placebo group of a randomized controlled trial to evaluate the relations of disease and host characteristics with time to first bone metastases in men with prostate cancer, rising prostate-specific antigen (PSA) despite androgen deprivation therapy, and no radiographic evidence of metastases. Relations between baseline covariates and clinical outcomes were assessed by Cox proportional hazard analyses. Covariates in the model were age, body mass index, prior prostatectomy, prior orchiectomy, Gleason score, performance status, PSA, urinary N-telopeptide, bone alkaline phosphatase, albumin, lactate dehydrogenase, and hemoglobin.

RESULTS

At 2 years, 46% of subjects had developed bone metastases, and 20% had died. Median bone metastasis-free survival was 25 months. In multivariate analyses, baseline PSA ≥ 13.1 ng/mL was associated with shorter overall survival (relative risk [RR], 2.34; 95% confidence interval [CI], 1.71-3.21; P < .0001), time to first bone metastasis (RR, 1.98; 95% CI, 1.43-2.74; P < .0001), and bone metastasis-free survival (RR, 1.98; 95% CI, 1.45-2.70; P < .0001). PSA velocity was significantly associated with overall and bone metastasis-free survival. Other covariates were not consistently associated with clinical outcomes.

CONCLUSIONS

In men with progressive castration-resistant prostate cancer and no detectable metastases, baseline PSA was significantly associated with time to first bone metastasis, bone metastasis-free survival, and overall survival. Other disease and host characteristics, including body mass index and bone turnover markers, were not consistently associated with clinical outcomes.

PSA doubling time for prediction of [(11)C]choline PET/CT findings in prostate cancer patients with biochemical failure after radical prostatectomy

PURPOSE

Previous studies have shown that the positive detection rate of [(11)C]choline positron emission tomography/computed tomography (PET/CT) depends on prostate-specific antigen (PSA) plasma levels. This study compared PSA levels and PSA doubling time (PSADT) to predict [(11)C]choline PET/CT findings.

METHODS

PSADT was retrospectively calculated in 170 prostate cancer (PCa) patients with biochemical failure after radical prostatectomy who underwent [(11)C]choline PET/CT. PSADT was calculated as PSADT = ln2/m, where m is the slope of the linear regression line of the natural log of PSA values. At least three PSA measurements were used (median: 4; range: 3-16), separated by at least 3 months, each with a minimum increase of 0.20 ng/ml. PET/CT findings were validated using criteria based on histological analysis and clinical and imaging data. Statistical analysis was performed using the t test, chi-square test, analysis of variance and binary logistic regression. Regression-based coefficients were used to develop a nomogram predicting the probability of positive [(11)C]choline PET/CT and 200 bootstrap resamples were used for internal validation.

RESULTS

The median PSA was 1.25 ng/ml (range: 0.23-48.6 ng/ml), and the median PSADT was 7.0 months (range: 0.97-45.3 months). [(11)C]choline PET/CT was positive in 75 of 170 patients (44%). PET/CT findings were validated using histological criteria (11%) and clinical and imaging criteria (89%). The overall accuracy of [(11)C]choline PET/CT was 88%. Multivariate logistic regression showed that high PSA and short PSADT were significant (p < 0.05) predictors of positive [(11)C]choline PET/CT [PSA: odds ratio (OR) = 1.43; 95% confidence interval (CI): 1.15-1.78; PSADT: OR = 1.12; 95% CI: 1.04-1.21]. The percentage of patients with positive [(11)C]choline PET/CT was 27% for PSADT >6 months, 61% for PSADT between 3 and 6 months and 81% for PSADT <3 months. The percentage of patients who displayed pathological [(11)C]choline uptake in the skeleton significantly increased (p < 0.05) from 3% for PSADT >6 months to 52% for PSADT <3 months. Conversely, patients who displayed pathological [(11)C]choline uptake in the prostatectomy bed were 0% for PSADT <3 months and 17% for PSADT >6 months (p < 0.05). A nomogram based on age, PSA, PSADT, time to trigger PSA, Gleason score, pathological stage and androgen deprivation therapy demonstrated bootstrap-corrected predictive accuracy of 81%.

CONCLUSION

Like PSA, PSADT is an independent predictor of [(11)C]choline PET/CT. [(11)C]choline PET/CT is very sensitive to PCa tumour growth, as reflected by PSA kinetics. PSADT should be taken into account by physicians when referring PCa patients for [(11)C]choline PET/CT.

Development and validation of a dynamic prognostic tool for prostate cancer recurrence using repeated measures of posttreatment PSA: a joint modeling approach

Prostate-specific antigen (PSA) is a biomarker routinely and repeatedly measured on prostate cancer patients treated by radiation therapy (RT). It was shown recently that its whole pattern over time rather than just its current level was strongly associated with prostate cancer recurrence. To more accurately guide clinical decision making, monitoring of PSA after RT would be aided by dynamic powerful prognostic tools that incorporate the complete posttreatment PSA evolution. In this work, we propose a dynamic prognostic tool derived from a joint latent class model and provide a measure of variability obtained from the parameters asymptotic distribution. To validate this prognostic tool, we consider predictive accuracy measures and provide an empirical estimate of their variability. We also show how to use them in the longitudinal context to compare the dynamic prognostic tool we developed with a proportional hazard model including either baseline covariates or baseline covariates and the expected level of PSA at the time of prediction in a landmark model. Using data from 3 large cohorts of patients treated after the diagnosis of prostate cancer, we show that the dynamic prognostic tool based on the joint model reduces the error of prediction and offers a powerful tool for individual prediction.

Determinants of change in prostate-specific antigen over time and its association with recurrence after external beam radiation therapy for prostate cancer in five large cohorts

PURPOSE

To assess the relationship between prognostic factors, postradiation prostate-specific antigen (PSA) dynamics, and clinical failure after prostate cancer radiation therapy using contemporary statistical models.

METHODS AND MATERIALS

Data from 4,247 patients with 40,324 PSA measurements treated with external beam radiation monotherapy in five cohorts were analyzed. Temporal change of PSA after treatment completion was described by a specially developed linear mixed model that included standard prognostic factors. These factors, along with predicted PSA evolution, were incorporated into a Cox model to establish their predictive value for the risk of clinical recurrence over time.

RESULTS

Consistent relationships were found across cohorts. The initial PSA decline after radiation therapy was associated with baseline PSA and T-stage (p < 0.001). The long-term PSA rise was associated with baseline PSA, T-stage, and Gleason score (p < 0.001). The risk of clinical recurrence increased with current level (p < 0.001) and current slope of PSA (p < 0.001). In a pooled analysis, higher doses of radiation were associated with a lower long-term PSA rise (p < 0.001) but not with the risk of recurrence after adjusting for PSA trajectory (p = 0.63). Conversely, after adjusting for other factors, increased age at diagnosis was not associated with long-term PSA rise (p = 0.85) but was directly associated with decreased risk of recurrence (p < 0.001).

CONCLUSIONS

We conclude that a linear mixed model can be reliably used to construct typical patient PSA profiles after prostate cancer radiation therapy. Pretreatment factors along with PSA evolution and the associated risk of recurrence provide an efficient and quantitative way to assess the impact of risk factors on disease progression.

Current applications for prostate-specific antigen doubling time

OBJECTIVE

To review the current status of prostate-specific antigen doubling time (PSADT) as it pertains to the evolution of prostate cancer (PCa), specifically assessing its role in the following four stages: before diagnosis, prior to definitive treatment, following treatment including salvage therapy after recurrence, and lastly, after onset of androgen-insensitive PCa.

METHODS

We searched PubMed literature for current articles on PSADT using the key words listed for this review and, where possible, selected those with significant levels of evidence that were deemed relevant, seminal, or controversial. We summarized the data regarding PSADT as a marker for diagnosis and disease characterization, as well as a predictor of progression, response to treatment, and mortality.

RESULTS

PSADT may offer an advantage in providing a more dynamic picture of tumor behavior, providing clues regarding the relative aggressiveness of the underlying pathology. Evidence points toward a role for PSADT in the management of PCa, specifically in active surveillance, disease recurrence after treatment, and in androgen-independent PCa. PSADT is an important prognostic factor that may serve as an auxiliary end point for cancer-specific survival; however, optimal cut-off points denoting risk remain debatable.

CONCLUSIONS

PCa management requires risk stratification with a combination of variables, PSADT being one of the most reliable predictors. It is now a parameter included in many predictive nomograms and in treatment guidelines for expectant management and salvage therapy.

Semiparametric modeling of longitudinal measurements and time-to-event data--a two-stage regression calibration approach

SUMMARY

In this article we investigate regression calibration methods to jointly model longitudinal and survival data using a semiparametric longitudinal model and a proportional hazards model. In the longitudinal model, a biomarker is assumed to follow a semiparametric mixed model where covariate effects are modeled parametrically and subject-specific time profiles are modeled nonparametrially using a population smoothing spline and subject-specific random stochastic processes. The Cox model is assumed for survival data by including both the current measure and the rate of change of the underlying longitudinal trajectories as covariates, as motivated by a prostate cancer study application. We develop a two-stage semiparametric regression calibration (RC) method. Two variations of the RC method are considered, risk set regression calibration and a computationally simpler ordinary regression calibration. Simulation results show that the two-stage RC approach performs well in practice and effectively corrects the bias from the naive method. We apply the proposed methods to the analysis of a dataset for evaluating the effects of the longitudinal biomarker PSA on the recurrence of prostate cancer.

Prostate specific antigen kinetics in the management of prostate cancer

PURPOSE

We review the usefulness of prostate specific antigen kinetics (ie prostate specific antigen velocity and doubling time) in the treatment of patients with prostate cancer.

MATERIALS AND METHODS

The MEDLINE database was searched to identify studies investigating prostate specific antigen kinetics in patients with prostate cancer.

RESULTS

Various techniques are available for estimating prostate specific antigen kinetics, but to minimize the impact of prostate specific antigen variability on such calculations at least a 90-day period and preferably more than 2 measurements should be used. There is little to suggest which measure of prostate specific antigen kinetics may be superior since both appear to provide useful prognostic information. Prostate specific antigen velocity is easier to calculate but prostate specific antigen doubling time may have greater biological justification. Retrospective studies show that before treatment prostate specific antigen kinetics provide prognostic information regarding the risk of treatment failure and subsequent death from cancer. Additionally, in patients treated surgically preoperative prostate specific antigen kinetics predict the risk of adverse pathology, while in those undergoing conservative treatment prostate specific antigen kinetics are associated with the risk of progression and need for intervention. In patients with biochemical failure after therapy prostate specific antigen kinetics predict the risk and potential site of clinical recurrence, the likely response to salvage therapy, and the risk of death from cancer. Preliminary assessments also suggest that prostate specific antigen kinetics may serve as a surrogate end point to replace cancer specific mortality.

CONCLUSIONS

Although prospective studies are lacking, the current literature suggests that prostate specific antigen kinetics provide valuable prognostic information, and should be further evaluated in clinical decision making and as a surrogate end point for future trials.

Prostate cancer gene therapy clinical trials

Despite recent advances in early detection and treatment, prostate cancer is still the second leading cause of cancer death in men in the United States, and approximately 27,000 men will die from it this year. Better treatments are needed for aggressive forms of localized disease and hormone-refractory metastatic disease. Recently, several gene therapy strategies have generated provocative results in early-stage clinical trials, raising the possibility that gene therapy may have the potential to affect both localized and metastatic disease. Much work lies ahead. Nevertheless, for the time being, these studies provide hope that gene therapy may someday earn a place in the management of prostate cancer.

Five-year follow-up of trial of replication-competent adenovirus-mediated suicide gene therapy for treatment of prostate cancer

Replication-competent adenovirus-mediated suicide gene therapy is an investigational cancer treatment that combines the oncolytic actions of human adenoviruses with the cytotoxic effects of chemo-radiosensitizing genes. Previously, we reported the short-term effects of this therapy in men with local recurrence of prostate cancer after definitive radiotherapy. With a median prostate-specific antigen (PSA) follow-up of 5 years, we report here the effect of the gene therapy on prostate-specific antigen doubling time (PSADT), a surrogate end point with significant prognostic power. When considering all evaluable subjects, the PSADT increased following the gene therapy from a mean of 17 to 31 months (median 16 to 22 months) (P=0.014). Assuming that salvage androgen suppression therapy androgen suppression therapy (AST) was uniformly initiated at a PSA of 15 ng/mL, the gene therapy would have delayed the projected onset of salvage therapy by an average of 2 years. The results indicate that replication-competent adenovirus-mediated suicide gene therapy may provide a potential long-term benefit to patients, as shown by a lengthening of the PSADT, and delay in when salvage therapy is indicated. Given the high morbidity associated with AST, we believe this approach could provide an attractive treatment option for selection of patients experiencing PSA relapse following definitive therapy.

Prostate specific antigen doubling time calculation: not as easy as 1, 2, 4

PURPOSE

Although prostate specific antigen doubling time is widely used to predict outcomes such as time to progression and prostate cancer specific mortality, clinicians may be unaware of the impact of method on prostate specific antigen doubling time calculation. We present a critical review of the literature to assess the diversity of methods used to calculate prostate specific antigen doubling time. We then describe the need for methodological consistency with the literature by showing examples from our clinical experience at our institution.

MATERIALS AND METHODS

A comprehensive review of articles evaluating prostate specific antigen doubling time as a prognostic and predictive indicator in various prostate cancer disease states was performed using PubMed. Case examples were drawn from the prostate cancer database at our institution. The database is a registry of 4,651 patients with prostate cancer who have been seen at our institution since 1998.

RESULTS

The methodology of prostate specific antigen doubling time calculation is inconsistent in the literature. Based on our experience and data presented in the literature the different methods in the literature are not always interchangeable. Small deviations from the methods outlined in a study can sometimes lead to wide variation in calculated prostate specific antigen doubling time. This variation of up to several months or longer is large enough to cause errors in assessment of prognosis and can even lead to incorrect management. The rules for prostate specific antigen doubling time calculation found in the literature can be categorized into 4 parameter groups, including method, calculation interval, data acquisition rules and data analysis rules. Case examples illustrate the importance of adherence to the literature with regard to each parameter.

CONCLUSIONS

Consistency with the literature in methodological elements of prostate specific antigen doubling time calculation is essential for the accurate calculation of prostate specific antigen doubling time. Clinicians and researchers should understand how methodological differences influence the value of calculated prostate specific antigen doubling time for purposes of patient care and research.

Unification of a common biochemical failure definition for prostate cancer treated with brachytherapy or external beam radiotherapy with or without androgen deprivation

PURPOSE

Minimal data are available regarding selection of an optimal biochemical failure (BF) definition for patients treated with brachytherapy, external beam radiotherapy (EBRT), and combinations of these treatments with or without androgen deprivation (AD). We retrospectively analyzed our institution's experience treating localized prostate cancer in an attempt to determine a BF definition that could be applied for these various treatment modalities.

METHODS AND MATERIALS

A total of 2376 patients with clinical stage T1-T3 N0 M0 prostate cancer were treated with conventional dose (median, 66.6 Gy) EBRT (n = 1201), high-dose (median, 75.6 Gy) adaptive radiation therapy (n = 465), EBRT + high-dose-rate brachytherapy boost (n = 416), or brachytherapy alone (n = 294) between 1987 and 2003. A total of 496 patients (21%) received neoadjuvant AD with radiation therapy. There were 21924 posttreatment prostate-specific antigen (PSA) measurements. Multiple BF definitions were tested for their sensitivity, specificity, positive predictive value (+PV), and negative PV (-PV) in predicting subsequent clinical failure (CF) (any local failure or distant metastasis), overall survival (OS), and cause-specific survival (CSS). Median follow-up was 4.5 years. The date of BF was the date BF criteria were met (e.g., date of third rise).

RESULTS

A total of 290 patients (12%) experienced CF at a median interval of 3.6 years (range, 0.2-15.2 years). The 5- and 10-year CF rates were 12% and 26%, respectively. Three consecutive rises yielded a 46% sensitivity and 84% specificity for predicting CF. The 10-year CF for those 475 patients who experienced three rises (BF) was 37% vs. 17% for those patients who did not meet these criteria (biochemically controlled [BC]). For all patients, the following definitions were superior to three rises for predicting CF for both +PV, and -PV: n + 1 (> or =1 ng/mL above nadir), n + 2, n + 3, threshold 2 (any PSA > or =2.0 ng/mL at or after nadir), threshold 3, threshold 4, and threshold 5. For the subset of patients treated with EBRT alone, the n + k definitions and threshold k definitions maintained superior predictive capacity. However, the threshold k definitions seemed to maintain a slightly greater separation in 10-year CF rates (43% for BF vs. 13% for BC = 30% difference for threshold 3). Surprisingly, all definitions generally had better predictive capacity for those patients who received brachytherapy or neoadjuvant AD vs. EBRT alone. The endpoints appeared similar for n + 1 vs. threshold 3 and n + 2 vs. threshold 4 in EBRT alone patients, but for brachytherapy or neoadjuvant AD patients, there were similarities for n + 2 vs. threshold 3 and n + 3 vs. threshold 4. This may be a reflection of the lower nadir levels in patients receiving AD (median <0.1 ng/mL vs. 0.2 ng/mL for brachytherapy vs. 0.8 ng/mL for EBRT alone, p < 0.01). When examining CF correlation for the various classes of BF definitions, the threshold k definitions clearly demonstrated the greatest area under the receiver operating characteristic curve, followed by the n + k definitions. For OS, the threshold k definitions again demonstrated the greatest area under the curve, followed by definitions based on specific nadir cutoffs (nadir > or =k ng/mL).

CONCLUSIONS

Biochemical failure definitions applying a PSA threshold at or after the nadir (e.g., threshold 3) demonstrated the highest association with CF, OS, and CSS for all assessed treatment modalities. Definitions incorporating a PSA increase above the nadir value (e.g., nadir + 2 ng/mL) were also superior for all modalities. In general, BF definitions have greater predictive capacity for clinical outcome with brachytherapy or neoadjuvant AD than EBRT alone, possibly because of less "noise" from production of background PSA.

Case-Matched comparison of contemporary radiation therapy to surgery in patients with locally advanced prostate cancer

PURPOSE

Few studies critically compare current radiotherapy techniques to surgery for patients with locally advanced prostate cancer, despite an urgent need to determine which approach offers superior cancer control. Our objective was to compare rates of biochemical relapse-free survival (BFS) and surrogates of disease specific survival among men with high risk adenocarcinoma of the prostate as a function of treatment modality.

METHODS AND MATERIALS

Retrospective data from 409 men with prostate-specific antigen (PSA) > or =10 or Gleason 7-10 or Stage > or =T2b cancer treated uniformly at one university between March 1988 and December 2000 were analyzed. Patients had undergone radical prostatectomy (RP), brachytherapy implant alone (BTM), or external beam radiotherapy with brachytherapy boost with short-term neoadjuvant and adjuvant androgen deprivation therapy (BTC). From the total study population a 1:1 matched-cohort analysis (208 patients matched via prostate-specific antigen, Gleason score) comparing RP with BTC was performed as well.

RESULTS

Estimated 4-year BFS rates were superior for patients treated with BTC (BTC 72%, BTM 25%, RP 53%; p < 0.001). Matched analysis of BTC vs. RP confirmed these results (BTC 73%, BTM 55%; p = 0.010). Relative risk (RR) of biochemical relapse for BTM and BTC compared with RP were 2.92 (1.95-4.36) and 0.56 (0.36-0.87), (p < 0.001, p = 0.010). RR for BTC from the matched cohort analysis was 0.44 (0.26-0.74; p = 0.002).

CONCLUSIONS

High-risk prostate cancer patients receiving multimodality radiation therapy (BTC) display apparently superior BFS compared with those receiving surgery (RP) or brachytherapy alone (BTM).

Use of prostate-specific antigen in the follow-up of patients with localized prostate cancer: results of a nationwide survey of urologists

OBJECTIVES

To perform a nationwide survey of urologists' opinions and behavior regarding the use of prostate-specific antigen (PSA) in prostate cancer follow-up and secondary treatment.

METHODS

A random sample of 300 urologists was interviewed. Content areas included defining recurrence in prostate cancer, factors that influence initiation of secondary treatment in this setting, and need for additional clinical trial information in recurrent prostate cancer.

RESULTS

Seventy-eight percent of urologists indicated that absolute PSA levels were of high or very high importance when making follow-up decisions. When defining a rising PSA level, 83% of urologists surveyed use the American Society for Therapeutic Radiology and Oncology definition of failure. An additional 78% use PSA doubling time. When asked about the importance of rapidly reducing PSA levels after recurrence, 61% said it was of high or very high importance to them, but 81% said it was of high or very high importance to their patients.

CONCLUSIONS

Results from the current study indicate that urologists consider PSA failure to be an important outcome in patients with prostate cancer. Researchers and policy makers need to consider this outcome when designing studies of prostate cancer.

Phase I-II prospective dose-escalating trial of lycopene in patients with biochemical relapse of prostate cancer after definitive local therapy

OBJECTIVES

To report a prospective trial of lycopene supplementation in biochemically relapsed prostate cancer.

METHODS

A total of 36 men with biochemically relapsed prostate cancer were enrolled in a dose-escalating, Phase I-II trial of lycopene supplementation. Six consecutive cohorts of 6 patients each received daily supplementation with 15, 30, 45, 60, 90, and 120 mg/day for 1 year. The serum levels of prostate-specific antigen (PSA) and plasma levels of lycopene were measured at baseline and every 3 months. The primary endpoints were PSA response (defined as a 50% decrease in serum PSA from baseline), pharmacokinetics, and the toxicity/tolerability of this regimen.

RESULTS

A total of 36 patients were enrolled. The median age was 74 years (range 56 to 83), with a median serum PSA at entry of 4.4 ng/mL (range 0.8 to 24.9). No serum PSA responses were observed, and 37% of patients had PSA progression. The median time to progression was not reached. Toxicity was mild, with 1 patient discontinuing therapy because of diarrhea. Significant elevations of plasma lycopene were noted at 3 months and then appeared to plateau for all six dose levels. The plasma levels for doses between 15 and 90 mg/day were similar, with additional elevation only at 120 mg/day.

CONCLUSIONS

Lycopene supplementation in men with biochemically relapsed prostate cancer is safe and well tolerated. The plasma levels of lycopene were similar for a wide dose range (15 to 90 mg/day) and plateaued by 3 months. Lycopene supplementation at the doses used in this study did not result in any discernible response in serum PSA.

Prostate specific antigen doubling time subsequent to radical prostatectomy as a prognosticator of outcome following salvage radiotherapy

PURPOSE

Therapy for men with detectable prostate specific antigen (PSA) following radical prostatectomy (RP) for prostate cancer remains controversial. Salvage radiotherapy (SRT) is commonly used because of its relatively low morbidity. We present a single institution retrospective review of patients treated with SRT.

MATERIALS AND METHODS

A longitudinal cohort study (between April 1987 and April 2000) using the referral based Mayo Clinic Prostate Cancer Registry was conducted. A total of 211 patients were included in this study if detectable serum PSA was the sole indication for SRT and no hormonal therapy was administered.

RESULTS

Median followup from surgery to death or last followup was 7.2 years, from RP to SRT was 1.7 years and from SRT to last contact was 4.2 years. Median PSA and prostate specific antigen doubling time (PSADT) at SRT initiation was 0.60 ng/ml and 7.32 months; respectively. Of the patients 90% had nadir PSA less than 0.4 ng/ml within 3 years of SRT. Biochemical disease-free rates at 5 years for PSADT less than 12 or 12 months or greater was 48% and 66%; respectively (p = 0.080). By 10 years there was no significant difference in biochemical disease-free rate (34% vs 35%). Clinical metastasis (10% and 29%) developed in patients with a PSADT less than 12 months at a significantly higher rate than in patients with a PSADT of 12 months or more (0% and 17%, p = 0.045) at 5 and 10 years, respectively. Multivariate analysis revealed pre-SRT PSADT (less than 12 months, H.R. 3.88, p = 0.032), seminal vesicle invasion (H.R. 3.22, p = 0.008), pathological grade (H.R. 1.58, p = 0.023) and PSA at SRT (H.R. 1.29 for a 2-fold increase, p = 0.044) to be significant independent predictors of clinical recurrence. The interval from RP to SRT did not add to the model (p = 0.22).

CONCLUSIONS

A biochemical response can be expected in the majority of patients within 3 years of receiving SRT. Patients with a pre-SRT PSADT of 1 year or less have a less sustained biochemical response to SRT than patients with a PSADT greater than 1, yet the majority of patients appear to receive long-term benefit from this adjunctive therapy. PSADT is an independent predictor of biochemical and clinical disease recurrence following SRT.

Biochemical Recurrence after Localized Treatment

The quoted incidence of biochemical recurrence (BCR) after localized treatment varies significantly and depends on numerous well-known prognostic factors; however, it likely occurs in at least 30%-40% of patients who receive localized treatment. Because the clinical significance of BCR is often unclear, and depends in many cases on unknown factors, it is difficult to select the best treatment and determine when best to institute that therapy. This review examines some of the issues associated with BCR and attempts to shed some light on this common but controversial clinical scenario. Some treatment strategies discussed in this article include salvage radiotherapy after radical prostatectomy, salvage therapy after radiotherapy, and hormonal therapy.

Predictors of prostate cancer-specific mortality after radical prostatectomy or radiation therapy

PURPOSE

We evaluated predictors of prostate cancer-specific mortality (PCSM) after prostate-specific antigen (PSA) failure after radical prostatectomy (RP) or radiation therapy (RT).

PATIENTS AND METHODS

A total of 1,159 men with clinically localized prostate cancer treated with RP (n = 498) or RT (n = 661) developed PSA failure, and they formed the study cohort. Competing risk regression analyses were used to evaluate whether previously identified predictors of time to metastasis, including post-treatment PSA doubling time (PSA-DT), Gleason score, and interval to PSA failure, could also predict time to PCSM after PSA failure. The cumulative incidence method was used to estimate PCSM after PSA failure.

RESULTS

A post-RP PSA-DT of less than 3 months (hazard ratio [HR], 54.9; 95% CI, 16.7 to 180), a post-RT PSA-DT of less than 3 months (HR, 12.8; 95% CI, 7.0 to 23.1), and a biopsy Gleason score of 8 to 10 (HR, 6.1; 95% CI, 3.4 to 10.7) for patients treated with RT were significantly associated with PCSM. Post-RP estimated rates of PCSM 5 years after PSA failure were 31% (95% CI, 17% to 45%) v 1% (95% CI, 0% to 2%) for patients with PSA-DT of less than 3 months v > or = 3 months. Post-RT estimated rates of PCSM 5 years after PSA failure were 75% (95% CI, 59% to 92%) v 35% (95% CI, 24% to 47%) for patients with a biopsy Gleason score of > or = 8 v < or = 7, respectively, and PSA-DT of less than 3 months; these rates were 15% (95% CI, 0.8% to 28%) v 4% (95% CI, 1% to 6%), respectively, for patients with a PSA-DT > or = 3 months.

CONCLUSION

Patients at high risk for PCSM after PSA failure can be identified based on post-RP PSA-DT or post-RT PSA-DT and biopsy Gleason score. These parameters may be useful in identifying patients for a randomized trial evaluating hormonal therapy with or without docetaxel.

When Prostate Brachytherapy Fails: A Case Report and Discussion

For appropriately selected brachytherapy patients, prostate-specific antigen failure is uncommon. Our patient experienced biochemical failure after 125I brachytherapy treatment for low-risk prostate adenocarcinoma. We suggest neoadjuvant/adjuvant hormonal therapy combined with pelvic external-beam radiation therapy as a reasonable salvage treatment. At the 2-year follow-up, he is apparently doing well. With limited data available, salvage management for this situation is presently investigational.

PSA nadir predicts biochemical and distant failures after external beam radiotherapy for prostate cancer: a multi-institutional analysis

PURPOSE

To determine the significance of prostate-specific antigen (PSA) nadir (nPSA) and the time to nPSA (T(nPSA)) in predicting biochemical or clinical disease-free survival (PSA-DFS) and distant metastasis-free survival (DMFS) in patients treated with definitive external beam radiotherapy (RT) for clinical Stage T1b-T2 prostate cancer.

METHODS AND MATERIALS

Nine participating institutions submitted data on 4839 patients treated between 1986 and 1995 for Stage T1b-T2cN0-NxM0 prostate cancer. All patients were treated definitively with RT alone to doses > or =60 Gy, without neoadjuvant or planned adjuvant androgen suppression. A total of 4833 patients with a median follow-up of 6.3 years met the criteria for analysis. Two endpoints were considered: (1) PSA-DFS, defined as freedom from PSA failure (American Society for Therapeutic Radiology and Oncology definition), initiation of androgen suppression after completion of RT, or documented local or distant failure; and (2) DMFS, defined as freedom from clinically apparent distant failure. In patients with failure, nPSA was defined as the lowest PSA measurement before any failure. In patients without failure, nPSA was the lowest PSA measurement during the entire follow-up period. T(nPSA) was calculated from the completion of RT to the nPSA date.

RESULTS

A greater nPSA level and shorter T(nPSA) were associated with decreased PSA-DFS and DMFS in all patients and in all risk categories (low [Stage T1b, T1c, or T2a, Gleason score < or =6, and PSA level < or =10 ng/mL], intermediate [Stage T1b, T1c, or T2a, Gleason score < or =6, and PSA level >10 but < or =20 ng/mL, or Stage T2b or T2c, Gleason score < or =6, and PSA level < or =20 ng/mL, or Gleason score 7 and PSA level < or =20 ng/mL], and high [Gleason score 8-10 or PSA level >20 ng/mL]), regardless of RT dose. The 8-year PSA-DFS and DMFS rate for patients with nPSA <0.5 ng/mL was 75% and 97%; nPSA > or =0.5 but <1.0 ng/mL, 52% and 96%; nPSA > or =1.0 but <2.0 ng/mL, 40% and 91%; and nPSA > or =2.0 ng/mL, 17% and 73%, respectively. The 8-year PSA-DFS and DMFS rate for patients with T(nPSA) <6 months was 27% and 66%; T(nPSA) > or =6 but <12 months, 31% and 85%; T(nPSA) > or =12 but <24 months, 42% and 94%; and T(nPSA) > or =24 months, 75% and 99%, respectively. A shorter T(nPSA) was associated with decreased PSA-DFS and DMFS, regardless of the nPSA. Both nPSA and T(nPSA) were significant predictors of PSA-DFS and DMFS in multivariate models incorporating clinical stage, Gleason score, initial PSA level, and RT dose. The significance of nPSA and T(nPSA) was supported by landmark analysis, as well as by analysis of nPSA and T(nPSA) as time-dependent covariates. A dose > or =70 Gy was associated with a lower nPSA level and longer T(nPSA) in all risk categories, and a greater dose was significantly associated with greater PSA-DFS and DMFS in multivariate analysis. Regression analysis confirmed that higher clinical stage, Gleason score, and initial PSA were associated with a greater nPSA level.

CONCLUSION

The results of this large, multi-institutional analysis of 4833 patients have provided important evidence that nPSA and T(nPSA) after definitive external beam RT are not only predictive of a predominantly PSA endpoint (PSA-DFS), but are also predictive of distant metastasis in all clinical risk categories. Greater RT doses were associated with lower nPSA, longer T(nPSA), and improved PSA-DFS and DMFS.

[PSA recurrence after primary curative therapy--local or systemic? When is a second curative therapy still possible?]

PSA recurrence after primary curative therapy for localized prostate cancer is a common problem. Further curative treatment is only reasonable in the case of local recurrence. Therefore, minimizing the likelihood of metastatic disease is crucial. So far, imaging techniques cannot distinguish between local recurrence and distant metastasis. It is therefore reasonable to orientate on PSA kinetics and pathological criteria. Histologic confirmation of suspected local recurrence after radical prostatectomy before salvage therapy is not required. However, after initial radiation therapy histologic confirmation of suspected isolated local recurrence should be obtained. The optimal treatment for a PSA recurrence depends on the initial therapy and the life-expectancy of the patient.

Natural history of rising serum prostate-specific antigen in men with castrate nonmetastatic prostate cancer

PURPOSE

To describe the natural history of nonmetastatic prostate cancer and rising prostate-specific antigen (PSA) despite androgen deprivation therapy.

PATIENTS AND METHODS

The 201 patients in this report were the placebo control group from an aborted randomized controlled trial to evaluate the effects of zoledronic acid on time to first bone metastasis in men with prostate cancer, no bone metastases, and rising PSA despite androgen deprivation therapy. Relationships between baseline covariates and clinical outcomes were assessed by Cox proportional hazard analyses. Covariates in the model were baseline PSA, Gleason sum, history of bilateral orchiectomies, regional lymph node metastases at diagnosis, prior prostatectomy, time from androgen deprivation therapy to random assignment, time from diagnosis to random assignment, and PSA velocity.

RESULTS

At 2 years, 33% of patients had developed bone metastases. Median bone metastasis-free survival was 30 months. Median time to first bone metastases and overall survival were not reached. Baseline PSA level greater than 10 ng/mL (relative risk, 3.18; 95% CI, 1.74 to 5.80; P < .001) and PSA velocity (4.34 for each 0.01 increase in PSA velocity; 95% CI, 2.30 to 8.21; P < .001) independently predicted shorter time to first bone metastasis. Baseline PSA and PSA velocity also independently predicted overall survival and metastasis-free survival. Other covariates did not consistently predict clinical outcomes.

CONCLUSION

Men with nonmetastatic prostate cancer and rising PSA despite androgen deprivation therapy have a relatively indolent natural history. Baseline PSA and PSA velocity independently predict time to first bone metastasis and survival.

LIMITATIONS IN THE USE OF SERUM PROSTATE SPECIFIC ANTIGEN LEVELS TO MONITOR PATIENTS AFTER TREATMENT FOR PROSTATE CANCER

PURPOSE

We reviewed the literature to help clarify the benefits and/or hazards associated with monitoring serum prostate specific antigen (PSA) after treatment with surgery or radiation therapy (RT) for nonmetastatic prostate cancer.

MATERIALS AND METHODS

A search was performed for 1990 to 2004 using the MEDLINE database, CancerLit database and reference lists of relevant studies to obtain articles addressing the use of serum PSA to follow patients after treatment for prostate cancer. Studies were reviewed to determine 1) if serial PSA monitoring provides an early and accurate surrogate assessment of cancer cure or treatment failure, 2) if any pattern in the PSA profile after treatment provides conclusive evidence of early local vs systemic failure, 3) the magnitude of the lead time to clinical failure that serial PSA monitoring may provide and 4) if the early identification of biochemical failure (BF) with earlier intervention improves outcome.

RESULTS

Although a lower PSA nadir after treatment with RT has been associated with cancer cure, 5% to 25% of patients ultimately have failure (beyond 5 years) even with the most optimal biochemical response. The most appropriate BF definitions to use after treatment for prostate cancer with RT remains controversial due to substantial differences in their accuracy, sensitivity, specificity and positive predictive value for clinical outcome. No pattern of PSA kinetics after treatment has conclusively been associated with a specific recurrence site. Biochemical failure definitions in patients treated with RT appear to provide a 6 to 18 month lead time to clinical failure but there are only limited published data to suggest that early intervention of any type (androgen deprivation, RT, surgery, etc) impacts survival.

CONCLUSIONS

The overall benefit of monitoring serum PSA after treatment for prostate cancer remains controversial. Considering the potential dangers associated with incorrectly assuming the efficacy of new forms of treatment, the toxicity of administering salvage therapies of uncertain efficacy after BF has been identified and the anxiety associated with tracking posttreatment serum PSA, additional studies must be done to determine the appropriate use of this marker in properly treating patients after therapy.