Intermediate End Point for Prostate Cancer-Specific Mortality Following Salvage Hormonal Therapy for Prostate-Specific Antigen Failure

Prognostic Value of Biochemical Recurrence Following Treatment with Curative Intent for Prostate Cancer: A Systematic Review

CONTEXT

In men with prostate cancer (PCa) treated with curative intent, controversy exists regarding the impact of biochemical recurrence (BCR) on oncological outcomes.

OBJECTIVE

To perform a systematic review of the existing literature on BCR after treatment with curative intent for nonmetastatic PCa. Objective 1 is to investigate whether oncological outcomes differ between patients with or without BCR. Objective 2 is to study which clinical factors and tumor features in patients with BCR have an independent prognostic impact on oncological outcomes.

EVIDENCE ACQUISITION

Medline, Medline In-Process, Embase, and the Cochrane Central Register of Controlled Trials were searched. For objective 1, prospective and retrospective studies comparing survival outcomes of patients with or without BCR following radical prostatectomy (RP) or radical radiotherapy (RT) were included. For objective 2, all studies with at least 100 participants and reporting on prognostic patient and tumor characteristics in patients with BCR were included. Risk-of-bias and confounding assessments were performed according to the Quality in Prognosis Studies tool. Both a narrative synthesis and a meta-analysis were undertaken.

EVIDENCE SYNTHESIS

Overall, 77 studies were included for analysis, of which 14 addressed objective 1, recruiting 20 406 patients. Objective 2 was addressed by 71 studies with 29 057, 11 301, and 4272 patients undergoing RP, RT, and a mixed population (mix of patients undergoing RP or RT as primary treatment), respectively. There was a low risk of bias for study participation, confounders, and statistical analysis. For most studies, attrition bias, and prognostic and outcome measurements were not clearly reported. BCR was associated with worse survival rates, mainly in patients with short prostate-specific antigen doubling time (PSA-DT) and a high final Gleason score after RP, or a short interval to biochemical failure (IBF) after RT and a high biopsy Gleason score.

CONCLUSIONS

BCR has an impact on survival, but this effect appears to be limited to a subgroup of patients with specific clinical risk factors. Short PSA-DT and a high final Gleason score after RP, and a short IBF after RT and a high biopsy Gleason score are the main factors that have a negative impact on survival. These factors may form the basis of new BCR risk stratification (European Association of Urology BCR Risk Groups), which needs to be validated formally.

PATIENT SUMMARY

This review looks at the risk of death in men who shows rising prostate-specific antigen (PSA) in the blood test performed after curative surgery or radiotherapy. For many men, rising PSA does not mean that they are at a high risk of death from prostate cancer in the longer term. Men with PSA that rises shortly after they were treated with radiotherapy or rapidly rising PSA after surgery and a high tumor grade for both treatment modalities are at the highest risk of death. These factors may form the basis of new risk stratification (European Association of Urology biochemical recurrence Risk Groups), which needs to be validated formally.

Hormone naïve prostate cancer: predicting and maximizing response intervals

Hormone naïve advanced prostate cancer is subdivided into two disease states: biochemical recurrence and traditional M1 (metastatic) prostate cancer and characterized by no prior hormonal therapy or androgen deprivation therapy (ADT). In biochemical recurrence/prostate-specific antigen (PSA) recurrence, men should be risk-stratified based on their PSA doubling time, the Gleason score and the timing of the recurrence. In general, only men who are at high risk should be considered for early/immediate ADT although this is best done using shared decision with the patient. The type of ADT to be used in biochemical recurrence ranging from oral-only peripheral blockade (peripheral androgen deprivation) to complete hormonal therapy (combined androgen blockade [CAB]) remains in debate owing to lack of randomized controlled trials (RCT). However, there is good RCT support for use of intermittent hormonal therapy (IHT). There is also limited research on biomarker response (PSA and testosterone decline) to predict prognosis. On the other hand, in the setting of M1 hormone naïve prostate cancer, there are many more RCT's to inform our decisions. CAB and gonadotrophin-releasing hormone antagonists perhaps provide a slight efficacy advantage while IHT may be slightly inferior with minimal M1 disease. The PSA nadir at 7 months after starting ADT is a powerful prognostic tool for M1 patients. There is growing recognition that serum testosterone (T) control while on ADT is linked to the development of castrate-resistant prostate cancer. Especially for a M1 patient, maintaining a serum T below 20–30 ng dl⁻¹ prolongs the response to ADT. Novel oral agents (abiraterone and enzalutamide) may soon find use in hormone naïve disease and may alter the treatment landscape. Despite over 75 years of experience with ADT, many questions remain, and the field continues to evolve.

Androgen deprivation decreases prostate specific antigen in the absence of tumor: implications for interpretation of PSA results

Background: Prostate-specific antigen (PSA) is used as an outcome measure for relapsed disease in prostate cancer. Nonetheless, there are considerable concerns about its indiscriminate use as a surrogate endpoint for cell growth or survival. We hypothesized that treatment with a luteinizing hormone releasing hormone (LHRH) analog would decrease PSA levels even in the absence of malignant disease.

Methods: We determined testosterone and PSA levels in 30 healthy volunteers after a single intramuscular injection of a LHRH depot formulation. Testosterone and PSA levels were quantified by radioimmunoassay and electrochemi-luminescence immunoassay, respectively.

Results: After an initial flare-up during the first 3 days testosterone decreased reaching castration levels in 18 of the 30 young men (60%). After the nadir on day 28, testosterone levels increased to normal again. Changes in PSA paralleled those of testosterone. Castration reduced PSA levels by 29% (95% CI 19%–39%) compared to baseline (p<0.0001).

Conclusions: LHRH superagonists decrease PSA levels by testosterone deprivation. Conferring these findings to tumor patients, decreases in PSA after treatment with LHRH analogs might not only reflect disease regression but also a direct testosterone mediated effect on PSA. Thus, PSA levels should be cautiously interpreted when patients receive hormonal therapy.

Timing of curative treatment for prostate cancer: a systematic review

CONTEXT

Delaying definitive therapy unfavourably affects outcomes in many malignancies. Diagnostic, psychological, and logistical reasons but also active surveillance (AS) strategies can lead to treatment delay, an increase in the interval between the diagnosis and treatment of prostate cancer (PCa).

OBJECTIVE

To review and summarise the current literature on the impact of treatment delay on PCa oncologic outcomes.

EVIDENCE ACQUISITION

A comprehensive search of PubMed and Embase databases until 30 September 2012 was performed. Studies comparing pathologic, biochemical recurrence (BCR), and mortality outcomes between patients receiving direct and delayed curative treatment were included. Studies presenting single-arm results following AS were excluded.

EVIDENCE SYNTHESIS

Seventeen studies were included: 13 on radical prostatectomy, 3 on radiation therapy, and 1 combined both. A total of 34 517 PCa patients receiving radical local therapy between 1981 and 2009 were described. Some studies included low-risk PCa only; others included a wider spectrum of disease. Four studies found a significant effect of treatment delay on outcomes in multivariate analysis. Two included low-risk patients only, but it was unknown whether AS was applied or repeat biopsy triggered active therapy during AS. The two other studies found a negative effect on BCR rates of 2.5-9 mo delay in higher risk patients (respectively defined as any with T ≥ 2b, prostate-specific antigen >10, Gleason score >6, >34-50% positive cores; or D'Amico intermediate risk-group). All studies were retrospective and nonrandomised. Reasons for delay were not always clear, and time-to-event analyses may be subject to bias.

CONCLUSIONS

Treatment delay of several months or even years does not appear to affect outcomes of men with low-risk PCa. Limited data suggest treatment delay may have an impact on men with non-low-risk PCa. Most AS protocols suggest a confirmatory biopsy to avoid delaying treatment in those who harbour higher risk disease that was initially misclassified.

Hormone use after radiotherapy failure: a survey of Canadian uro-oncology specialists

INTRODUCTION

A survey of Canadian uro-oncology specialists was performed to assess practice patterns of patients with recurrent prostate cancer postradiotherapy and to assess the feasibility of conducting a trial in this setting.

METHODS

There were 14 survey questions and 1 demographic question. Responses were reported by frequency.

RESULTS

There were 96 respondents. Most respondents use both prostate-specific antigen doubling time (PSAdt) and PSA level when deciding to start androgen deprivation therapy (ADT) in asymptomatic patients. About half of respondents start ADT when PSA is greater than 10 ng/mL or when the PSAdt is less than 6 months. Eighty-six percent felt that the timing of ADT was an important research question. Over 1500 patients per year were estimated as being available for such a trial.

CONCLUSION

After radiotherapy failure, respondents initiated ADT about half of the time when PSA is less than 10 ng/mL and/or PSAdt is less than 6 months. A clinical trial examining the timing of ADT has strong support and appears to be feasible.

Hormonal approaches in prostate cancer: application in the contemporary prostate cancer patient

Early studies beginning in the 1940s confirmed the importance of the androgen receptor and benefits of androgen depletion in metastatic prostate cancer. These studies helped to establish management strategies with an excellent response rate. Despite this, there remains some controversy as to the optimal approach for patients. Fueling this controversy is the fact that routine PSA testing did not come into practice until the early 1990s, while the majority of the large trials evaluating the use of hormonal therapy were conducted in the pre-PSA era and in patients who had metastatic disease identifiable with radiographic imaging. With the onset of routine PSA testing and the subsequent stage migration that has occurred in men presenting with prostate cancer, the question of when to initiate hormonal therapy has become ever more controversial.

Prognostic and Predictive Factors in Patients with Androgen-Independent Prostate Cancer Treated with Docetaxel and Estramustine: A Single Institution Experience

OBJECTIVES

To investigate potential prognostic and predictive factors in patients with androgen-independent prostate cancer (AIPC) treated with docetaxel chemotherapy.

METHODS

This analysis included 94 consecutive AIPC patients who were treated between March 2001 and May 2006 with biweekly docetaxel 45 mg/m(2) (day 2) and estramustine 140 mg three dimes daily (days 1-3).

RESULTS

Prostate-specific antigen (PSA) responses were observed in 45 of 84 evaluable patients (53%), whereas objective responses were observed in 16 of 40 patients with measurable disease (40%). Median survival (OS) was 16.2 mo (95% confidence interval [CI], 12.9-19.4) and median time to PSA progression (TTP) 5.0 mo (95%CI, 3.6-7.1). OS was independently associated with pain score baseline PSA and weight loss. Patients with only extraosseous disease had higher PSA response rate (87% vs. 49%, p=0.014) and superior TTP compared with patients with bone metastases with or without extraosseous disease (7.3 vs. 4.3 vs. 4 mo, p=0.002). Concurrent bone and extraosseous metastases were associated with worse prognosis compared with each site alone (median OS: 12.3 vs.19 vs.18.3 mo, p=0.007).

CONCLUSIONS

Among patients with AIPC treated with biweekly docetaxel and estramustine, baseline PSA >100, existence of pain, weight loss, and simultaneous extraosseous and bone disease were associated with worse prognosis. Extraosseous metastases seem to be more sensitive than bone disease to this chemotherapy.

Prostate-specific antigen and pain surrogacy analysis in metastatic hormone-refractory prostate cancer

PURPOSE

It is currently unclear if early prostate-specific antigen (PSA) or pain improvements are adequate surrogates for overall survival in men with metastatic hormone-refractory prostate cancer (HRPC). Here we examined various degrees of PSA decline and pain response as surrogates for the survival benefit observed in the TAX327 trial.

PATIENTS AND METHODS

In the TAX327 trial, 1,006 men with HRPC were randomly assigned to receive docetaxel in two schedules, or mitoxantrone, each with prednisone: 989 men provided data on 3-month PSA decline. Surrogacy was examined for post-treatment changes in PSA and pain response using Cox proportional hazards models to calculate the proportion of treatment effect (PTE) explained by each potential surrogate.

RESULTS

A > or = 30% PSA decline within 3 months of treatment initiation provides the highest degree of surrogacy, with a PTE of 0.66 (95% CI, 0.23 to 1.0), and was associated with a hazard ratio (HR) of 0.50 (95% CI, 0.43 to 0.58) for overall survival after adjusting for treatment effect. Introduction of a > or = 30% PSA decline is predictive of survival regardless of treatment arm. Other changes in PSA or PSA kinetics, PSA normalization, and pain responses were highly prognostic but weaker surrogates for survival.

CONCLUSION

In the TAX327 trial, a PSA decline of > or = 30% within 3 months of chemotherapy initiation had the highest degree of surrogacy for overall survival, confirming data from the Southwest Oncology Group 9916 trial. However, given the wide CIs around the estimate of this moderate surrogate effect, overall survival should remain the preferred end point for phase III trials of cytotoxic agents in HRPC.

Prostate Specific Antigen Only Androgen Independent Prostate Cancer: Natural History, Challenges in Management and Clinical Trial Design

PURPOSE

There is no current standard of care for patients with nonmetastatic androgen independent prostate cancer, a condition defined by increasing serum prostate specific antigen despite anorchid testosterone levels and no radiographic evidence of metastases. A consensus panel was convened to review data and propose a strategy for trial design and prioritization.

MATERIALS AND METHODS

Published literature on the natural history of nonmetastatic androgen independent prostate cancer was reviewed. A panel discussion was held, focusing on reviewing current and past trials, and the development of research priorities for patients in this disease state.

RESULTS

Based on 1 report the natural history of nonmetastatic androgen independent prostate cancer is relatively long but heterogeneous. External validation of these published findings has not been performed. Clinical trial design in this setting is impeded by heterogeneity and lack of knowledge about the natural history, prolonged time to clinical end points, such as the development of metastases or death, and a lack of knowledge about how intermediate end points, eg the development of bone metastases, are related to the long-term outcome, eg survival. In clinical practice a reluctance to use therapies with substantial toxicity as well as a lack of outcome data on such patients leaves a vacuum in which there is no standard of care, although secondary hormonal manipulations are widely used.

CONCLUSIONS

Further research is needed to define the natural history of this disease state, educate patients and clinicians about its distinct natural history and develop informative clinical trial designs suited to this patient population.

Initial hormonal management of androgen-sensitive metastatic, recurrent, or progressive prostate cancer: 2006 update of an American Society of Clinical Oncology practice guideline

PURPOSE

To update the 2004 American Society of Clinical Oncology (ASCO) guideline on initial hormonal management of androgen-sensitive, metastatic, recurrent, or progressive prostate cancer (PCa).

METHODS

The writing committee based its recommendations on an updated systematic literature review. Recommendations were approved by the Expert Panel, the ASCO Health Services Committee, and the ASCO Board of Directors.

RESULTS

Seven randomized controlled trials (four new), one systematic review, one meta-analysis (new), one Markov model, and one delta-method 95% CI procedure for active controlled trials (new) informed the guideline update.

RECOMMENDATIONS

Bilateral orchiectomy or luteinizing hormone-releasing hormone agonists are recommended initial androgen-deprivation treatments (ADTs). Nonsteroidal antiandrogen monotherapy merits discussion as an alternative; steroidal antiandrogen monotherapy should not be offered. Combined androgen blockade should be considered. In metastatic or progressive PCa, immediate versus symptom-onset institution of ADT results in a moderate decrease (17%) in relative risk (RR) for PCa-specific mortality, a moderate increase (15%) in RR for non-PCa-specific mortality, and no overall survival advantage. Therefore, the Panel cannot make a strong recommendation for early ADT initiation. Prostate-specific antigen (PSA) kinetics and other metrics allow identification of populations at high risk for PCa-specific and overall mortality. Further studies must be completed to assess whether patients with adverse prognostic factors gain a survival advantage from immediate ADT. For patients electing to wait until symptoms for ADT, regular monitoring visits are indicated. For patients with recurrence, clinical trials should be considered if available. Currently, data are insufficient to support use of intermittent androgen blockade outside clinical trials

Post-therapy changes in PSA as an outcome measure in prostate cancer clinical trials

To the investigator and clinician, prostate-specific antigen (PSA) level is a seemingly perfect outcome measure because it is easily assessable, quantitative, reproducible, and inexpensive. Whether post-therapy decline in PSA reflects true clinical benefit, and whether post-therapy declines can be used as an intermediate endpoint for accelerated drug approval is still open to question. At present, no drug has been approved strictly on the basis of a post-treatment decline in PSA, as it is unproven that such PSA changes are surrogates for true clinical benefits. Post-therapy PSA changes have been associated with improved survival in patients with castrate metastatic disease. The role of PSA changes as potential surrogates of clinical benefit have only been explored to a limited degree because to date, only two prospective randomized trials showing a survival benefit have been reported. Such trials are necessary, but not a sufficient pre-requisite to explore the potential role of any outcome measure as an intermediate endpoint. The clear demonstration that a post-therapy PSA change can account for all of the treatment effects seen is not yet available. A cytotoxic drug that does not produce any PSA decline is unlikely to be effective, but the converse is not always true because not all PSA rises represent a treatment failure. It is important to recognize that there are a range of clinical benefits to patients that can improve the quality and possibly the duration of survival, independent of PSA.

Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided high dose rate brachytherapy boost

Purpose

To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost.

Materials and methods

Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml.

Results

Median follow-up was 24 months (range 18–36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6.

Conclusion

We observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive.

Intermittent androgen deprivation: clinical experience and practical applications

Prostate cancer is more frequently being diagnosed at an earlier age, men are dying of prostate cancer at an older age, and men are now treated with androgen deprivation for biochemical relapse. As a result, the amount of time that patients are potentially subjected to androgen deprivation is increasing. Intermittent androgen deprivation (IAD) has been investigated as a potential alternative to continuous androgen deprivation (CAD) in order to improve quality of life and potentially delay the progression to androgen independence. Along with the increased use of primary hormonal therapy in clinically localized prostate cancer, IAD may supplant the traditional surgical or radiotherapy options, specifically in men who have underlying co-morbidities and decreased life expectancy. There are ongoing multi-institutional, randomized trials that will lend insight into the utility, efficacy, and feasibility of IAD versus CAD. This article discusses the theoretical benefits and rationale of IAD and reviews the completed and on-going IAD trials. Finally, the controversies, practical applications, and future directions of IAD are addressed.

Intermittent androgen ablation in patients with biochemical failure after pelvic radiotherapy for localized prostate cancer

PURPOSE

To assess the efficacy of intermittent androgen ablation (IAA) in patients with biochemical failure after radiotherapy for prostate cancer.

METHODS AND MATERIALS

Thirty-nine patients received a luteinizing hormone-releasing hormone analog every 2 months for a total of 4 doses. IAA was then discontinued if serum prostate-specific antigen (PSA) fell to a normal level with a castrate level of testosterone. Therapy was restarted when the serum PSA level reached > or = 10 ng/mL and was discontinued if hormone resistance or unacceptable toxicity occurred.

RESULTS

Median PSA was 9.1 ng/mL at the time of first IAA. The median time between the first and the second cycles was 20.1 months, decreasing to 15.5 months between the third and fourth cycles. Two patients discontinued the treatment because of severe hot flushes. Four patients developed hormone resistance. With a median follow-up of 56.4 months, 5-year survival is 92.3%. Three patients died of unrelated causes. The incidence of distant metastasis is 6.8%.

CONCLUSIONS

The use of IAA seems to be a safe and effective treatment for patients with biochemical failure post radiotherapy and no evidence of metastatic disease. The use of IAA limits hormone-related side effects and health care costs without an apparent increase in the risk for the development of metastatic disease.

Time to Detectable Metastatic Disease in Patients with Rising Prostate-Specific Antigen Values following Surgery or Radiation Therapy

PURPOSE

To determine factors associated with the development of radiographic metastatic progression for patients with recurrent prostate cancer following surgery and/or radiation therapy with prostate-specific antigen (PSA) doubling times of <12 months.

EXPERIMENTAL DESIGN

One hundred and forty-eight patients with rising PSA values after primary therapy and a PSA doubling time of <12 months enrolled on clinical protocols were followed and monitored at protocol-specified intervals with examinations, PSA determinations, and imaging studies that included a computed tomography or magnetic resonance imaging and bone scan until metastases were detected. Metastasis-free survival was estimated using the Kaplan-Meier method and factors predictive of progression-free survival were estimated using the proportional hazards model. A nomogram based on the Cox model was constructed.

RESULTS

Metastatic events were documented in 74% (110 of 148) of patients during the follow-up period. The median progression-free survival was 19 months, with 3- and 5-year metastatic progression-free survival of 32% and 16%, respectively. T stage (P=0.07) and Gleason grade (P=0.006) at the time of diagnosis, PSA values at the time of protocol entry (P<0.001), and PSA doubling time (P<0.001) were associated with progression in univariate analysis. These were combined into a nomogram to assess risk for an individual patient.

CONCLUSIONS

Tumor characteristics at the time of diagnosis, PSA doubling time following relapse, and the PSA value at the time of the protocol are predictive of metastatic progression. Because the PSA value at the time of monitoring was predictive, early treatment to prevent metastatic progression is favored.

Prognostic value of serum markers for prostate cancer

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Pretreatment predictors of posttreatment PSA doubling times for patients undergoing three-dimensional conformal radiotherapy for clinically localized prostate cancer

OBJECTIVES

To determine whether pretreatment risk groups also predict for posttreatment prostate-specific antigen (PSA) doubling times (PSADTs). Pretreatment risk groups predict for posttreatment biochemical failure (BF) after conformal radiotherapy in patients with prostate cancer and posttreatment PSADTs can predict for prostate cancer-related deaths.

METHODS

The study cohort consisted of 416 patients with clinically localized prostate cancer treated with conformal radiotherapy between 1989 and 2001. The patients were divided into low, intermediate, and high-risk groups. BF was defined using the American Society for Therapeutic Radiology and Oncology consensus definition. Patients with BF were grouped according to their PSADT (3 months or less, longer than 3 months to less than 6 months, 6 months to less than 12 months, and 12 months or longer). A Mantle-Haenszel chi-square metric tested for an association between the pretreatment risk group and the PSADT. Logistic regression multivariate analysis was performed to evaluate whether the pretreatment risk group predicted the PSADT.

RESULTS

Of the 416 patients, 96 (23%), 194 (47%), and 126 (30%) were categorized as low, intermediate, and high risk, respectively. A total of 92 patients (22%) experienced BF. Of these 92 patients, the PSADT was 3 months or less in 6 (7%), longer than 3 months to less than 6 months in 13 (14%), 6 months to less than 12 months in 35 (36%), and 12 months or longer in 38 (41%). The pretreatment risk group correlated significantly with the PSADT (P = 0.026). Logistic regression analysis revealed that intermediate and high-risk disease was significantly associated with shorter PSADTs (P = 0.039).

CONCLUSIONS

A significant association between the pretreatment risk group and posttreatment PSADT was demonstrated. Use of this selection criterion at diagnosis for more aggressive treatment appears warranted.

[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.

Pilot study: potential role of vitamin D (Cholecalciferol) in patients with PSA relapse after definitive therapy

When local treatments for prostate cancer have failed, and prostate-specific antigen (PSA) rises in the absence of symptoms, there is little consensus as to the best management strategy. Calcitriol has been shown to prolong the doubling time of PSA in this context, but near-toxic doses are required. We investigated the effect of the nutrient vitamin D (cholecalciferol), a biochemical precursor of calcitriol, on PSA levels and the rate of rise of PSA in these patients. Fifteen patients were given 2,000 IU (50 microg) of cholecalciferol daily and monitored prospectively every 2-3 mo. In 9 patients, PSA levels decreased or remained unchanged after the commencement of cholecalciferol. This was sustained for as long as 21 mo. Also, there was a statistically significant decrease in the rate of PSA rise after administration of cholecalciferol (P = 0.005) compared with that before cholecalciferol. The median PSA doubling time increased from 14.3 mo prior to commencing cholecalciferol to 25 mo after commencing cholecalciferol. Fourteen of 15 patients had a prolongation of PSA doubling time after commencing cholecalciferol. There were no side effects reported by any patient. Further study is needed to confirm this finding and to explore the potential therapeutic benefit of nutrient vitamin D in prostate cancer.

Prostate cancer clinical trial end points: "RECIST"ing a step backwards

PURPOSE

To relate clinical issues to the clinical manifestations of prostate cancers across disease states using the eligibility and outcome criteria defined by Response Evaluation Criteria in Solid Tumors (RECIST).

EXPERIMENTAL DESIGN

The manifestations of prostate cancer that characterize localized, recurrent, and metastatic disease were considered using the eligibility criteria for trials defined by RECIST. To do so, we analyzed the sites, size, and distribution of lesions in patients enrolled on contemporary Institutional Review Board-approved trials for progressive castrate and noncastrate metastatic disease. Prostate-specific antigen (PSA) levels were also assessed. RECIST-defined outcome measures for tumor regression were then applied to the metastatic patient cohorts, and separately to the states of a rising PSA (noncastrate and castrate) and localized disease.

RESULTS

Only 43.5% of men with castrate metastatic and 16% of noncastrate metastatic disease had measurable target lesions > 2 cm in size. Overall, 84.4% of the target lesions were lymph nodes, of which 67.7% were > or = 2 cm in the long axis. There are no target lesions in patients in the states of a rising PSA and localized disease, making them ineligible for trials under these criteria. PSA-based eligibility and outcomes under RECIST conflict with established reporting standards for the states of a rising PSA and castrate metastatic disease. The clinical manifestations of prostate cancer across multiple disease states are not addressed adequately using the eligibility criteria and outcomes measures defined by RECIST. Important treatment effects are not described.

CONCLUSIONS

Trial eligibility and end points based solely on tumor regression are not applicable to the majority of the clinical manifestations of prostate cancers representing all clinical states. Treatment effects can be described more precisely if eligibility criteria are adapted to the clinical question being addressed and clinical state under study, focusing on the duration of benefit defined biochemically, radiographically, and/or clinically.

SURROGATE END POINT FOR PROSTATE CANCER SPECIFIC MORTALITY IN PATIENTS WITH NONMETASTATIC HORMONE REFRACTORY PROSTATE CANCER

PURPOSE

We determined whether prostate specific antigen (PSA) velocity can serve as surrogate end point for prostate cancer specific mortality (PCSM) in patients with nonmetastatic, hormone refractory prostate cancer.

MATERIALS AND METHODS

The study cohort comprised 919 men treated from 1988 to 2002 at 1 of 44 institutions with surgery (560) or radiation therapy (359) for clinical stages T1c-4NxMo prostate cancer, followed by salvage hormonal therapy for PSA failure. All patients experienced PSA defined recurrence while on hormonal therapy. Prentice criteria require that the surrogate should be a prognostic factor and the treatment used did not alter time to PCSM following achievement of the surrogate end point. These criteria were tested using Cox regression. All statistical tests were 2-sided.

RESULTS

PSA velocity greater than 1.5 ng/ml yearly was statistically significantly associated with time to PCSM and all cause mortality following PSA defined recurrence while undergoing hormonal therapy (Cox p <0.0001). While initial treatment was statistically associated with time to PCSM and all cause mortality (Cox p = 0.001 and 0.01), this association became insignificant when PSA velocity and potential confounding variables were included in the Cox model (p = 0.22 and 0.93, respectively). The adjusted HR for PCSM in patients who experienced a greater than 1.5 ng/ml increase in PSA within 1 year while on hormonal therapy was 239 (95% CI 10 to 5,549).

CONCLUSIONS

These data provide evidence to support PSA velocity greater than 1.5 ng/ml yearly as a surrogate end point for PCSM in patients with nonmetastatic, hormone refractory prostate cancer. Enrolling these men onto clinical trials evaluating the impact of chemotherapy on time to bone metastases and PCSM is warranted.

Evidence-based medical perspectives: the evolving role of PSA for early detection, monitoring of treatment response, and as a surrogate end point of efficacy for interventions in men with different clinical risk states for the prevention and progression of prostate cancer

Following FDA approval and introduction into the clinic in the mid-1980s, PSA testing has become arguably the most versatile serum tumor marker in urologic oncology with clinical use for early detection (screening) of prostate cancer (PC), risk stratification for clinical staging, prognosis, intermediate biomarker for monitoring tumor recurrence, and more recently as an intermediate biomarker for assessing therapeutic response to antiandrogens, radiation therapy, and chemotherapy. PSA now routinely guides health care providers for the clinical management of PC over a wide range of clinical risk states for men at risk of PC, after local definitive therapy and after systemic therapy to prevent progression to metastatic bone disease, and to palliate men with hormone refractory prostate cancer (HRPC). To further assess the evidence that supports these clinical applications, this commentary reviews and critically evaluates the emerging body of new data focusing on several recently published seminal articles by D'Amico et al and Thompson et al, the new National Comprehensive Cancer Network 2004 recommendations for starting PSA testing at the age of 40 years old, the latest results from 2 phase 3 randomized, controlled trials of taxane-based regimens showing improved survival for men with HRPC, and the recent US FDA Public Workshop on Clinical Trial Endpoints in Prostate Cancer that helped to distill and synthesize the current state of the art and the progress toward validation of PSA metrics (eg, PSA velocity) as a surrogate end point (SE) for treatment efficacy with taxane-based regimens. Furthermore, several randomized, controlled chemoprevention trials in progress evaluating agents such as selenium and vitamin E in high-risk cohorts are well poised to confirm the validity of PSA as an SE for clinical efficacy for the prevention and progression of PC. Although there continues to be a need to validate better biomarkers before diagnosis of PC (more sensitive and specific) and after diagnosis to discern between indolent and aggressive forms of PC, it is very likely that some metric of PSA as a biomarker alone or as part of a panel of other serum proteomic markers or tissue-derived multiplex gene expression arrays will be around for years to come as a useful tool for risk stratification, early detection, prognosis, prediction, and as an SE of efficacy for prevention and treatment of PC.

The impact of a delay in initiating radiation therapy on prostate-specific antigen outcome for patients with clinically localized prostate carcinoma

BACKGROUND

To determine whether a delay in initiating external beam radiation therapy (RT) following diagnosis could impact prostate-specific antigen (PSA) outcome for patients with localized prostate cancer, 460 patients, who received 3D conformal RT to a median dose of 70.4 Gy for clinically localized prostate cancer between 1992 and 2001, were studied.

METHODS

The primary endpoint was PSA failure (American Society for Therapeutic Radiology and Oncology definition). Estimates of PSA control were made using the Kaplan-Meier method. Delay was defined as the time between diagnosis and the start of RT. Risk groups were defined based on known predictors of PSA outcome, namely, baseline PSA level, clinical T-category, Gleason score, and percentage of biopsy cores positive for tumor. Cox multivariate regression analysis was used to determine the ability of treatment delay to predict time to PSA failure after adjusting for the other known predictors.

RESULTS

Treatment delay independently predicted time to PSA failure following diagnosis for high-risk (Adjusted Hazard Ratio = 1.08 per month; P = 0.029) but not low-risk patients (P = 0.31). Patients with high-risk disease (n = 240) had 5-year estimates of PSA failure-free survival of 55% versus 39% (Plog-rank = 0.014) for those with delay < 2.5 months versus > or = 2.5 months respectively. The median delay was 2.5 months.

CONCLUSIONS

Treatment delay adversely affected PSA outcome for high-risk patients but not for low-risk patients following RT.