Wide variation of prostate-specific antigen doubling time of untreated, clinically localized, low-to-intermediate grade, prostate carcinoma

Prostate cancer trajectory-map: clinical decision support system for prognosis management of radical prostatectomy

Purpose

Prostate cancer has a low mortality rate and requires persistent treatment; however, treatment decisions are challenging. Because prostate cancer is complex, the outcomes warrant thorough follow-up evaluation for appropriate treatment. Electronic health records (EHRs) do not present intuitive information. This study aimed to develop a Clinical Decision Support System (CDSS) for prognosis management of radical prostatectomy.

Methods

We used data from 5,199 prostate cancer patients from three hospitals' EHRs in South Korea, comprising laboratory results, surgery, medication, and radiation therapy. We used open source R for data preprocessing and development of web-based visualization system. We also used R for automatic calculation functionalities of two factors to visualize the data, e.g., Prostate-Specific Antigen Doubling Time (PSADT), and four Biochemical Recurrence (BCR) definitions: American Society of Therapeutic Radiology and Oncology (ASTRO), Phoenix, consecutive PSA > 0.2 ng/mL, and PSA > 0.2 ng/mL.

Results

We developed the Prostate Cancer Trajectory Map (PCT-Map) as a CDSS for intuitive visualization of serial data of PSA, testosterone, surgery, medication, radiation therapy, BCR, and PSADT.

Conclusions

The PCT-Map comprises functionalities for BCR and PSADT and calculates and visualizes the newly added patient data automatically in a PCT-Map data format, thus optimizing the visualization of patient data and allowing clinicians to promptly access patient data to decide the appropriate treatment.

Collateral resistance to taxanes in enzalutamide-resistant prostate cancer through aberrant androgen receptor and its variants

Currently, the optimal sequential use of androgen receptor (AR) axis-targeted agents and taxane chemotherapies remains undetermined. We aimed to elucidate the resistance status between taxanes and enzalutamide, and the functional role of the AR axis. Enzalutamide-resistant 22Rv1 cells showed collateral resistance to taxanes, including docetaxel and cabazitaxel. However, taxane-resistant cells showed no collateral resistance to enzalutamide; taxane-resistant cells expressed comparable protein levels of full-length AR and AR variants. Knockdown of both full-length AR and AR variants rendered cells sensitive to taxanes, whereas knockdown of AR variants sensitized cells to enzalutamide, but not to taxanes. In contrast, overexpression of full-length AR rendered cells resistant to taxanes. Consistently, the prostate-specific antigen response and progression-free survival in docetaxel chemotherapy were worse in cases with prior use of ARAT agents compared with cases without. Collateral resistance to taxanes was evident after obtaining enzalutamide resistance, and aberrant AR signaling might be involved in taxane resistance.

Pretreatment prostate specific antigen doubling time as prognostic factor in prostate cancer patients

Despite the prostate-specific antigen (PSA) serum level commonly uses as tumor marker in diagnosis of prostate cancer, it seems that PSA doubling time (PSADT) could be more useful indicator of tumor behavior and of prognosis for patients. The results of hormone and radiation therapy were evaluated for 912 prostate cancer having at least 2 PSA tests before the treatment was started. Clustering procedure (selection of homogenous group) was performed by using PSADT as the classification marker. The rate of PSADT was estimated for different dissemination rate, age, Gleasons's score and education level. PSADT index inversely correlated with the rate of prostate cancer dissemination, Gleason's score and the level of education were directly correlated with the age of patients. Survival time was longer and PSADT index was higher in “slow” tumor growing subgroups in local, local-advanced and metastatic prostate cancer patients than these in “fast” subgroups. The study confirmed the prognostic value of pretreatment PSADT in prostate cancer patients independently of cancer progression. No significant relationship exists between the authors and the companies/organizations whose products or services may be referenced in this article.

[Active surveillance for low-risk prostate cancer]

Autopsy studies have confirmed the high prevalence of latent prostate cancer; however, only a certain portion of patients require definite treatment. Active surveillance is one of the treatment options which, according to national and international guidelines, should be offered to patients with newly diagnosed low-risk prostate cancer. Prostate cancer-specific survival is high in these patients; therefore, curative treatment, such as radical prostatectomy, external beam radiotherapy and brachytherapy may be initially deferred in order to avoid therapy-related side effects. In order to qualify for active surveillance, strict inclusion criteria have to be met; nevertheless, the reliable identification of low-risk prostate cancer patients is not always possible. Patients under active surveillance are followed up regularly with prostate-specific antigen (PSA) testing, digital rectal examination (DRE) and repeat prostate biopsies. Due to the heterogeneity of primary prostate tumors precise molecular diagnostic techniques could allow individualized treatment strategies in the future.

Radical prostatectomy versus watchful waiting for prostate cancer

BACKGROUND

The lack of evidence regarding the effectiveness of treatment options for clinically localised prostate cancer continues to impact on clinical decision-making. Two such options are radical prostatectomy (RP) and watchful waiting (WW). WW involves providing no initial treatment and monitoring the patient with the intention of providing palliative treatment if there is evidence of disease progression.

OBJECTIVES

To compare the beneficial and harmful effects of RP versus WW for the treatment of localised prostate cancer.

SEARCH STRATEGY

MEDLINE, EMBASE, The Cochrane Library, ISI Science Citation Index, DARE and LILACS were searched through 30 July 2010.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing the effects of RP versus WW for clinically localised prostate cancer.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment were carried out independently by two authors.

MAIN RESULTS

Two trials met the inclusion criteria. Both trials commenced prior to the widespread availability of prostate-specific antigen (PSA) screening; hence the results may not be applicable to men with PSA-detected disease.One trial (N = 142), conducted in the US, was judged to be of poor quality. All cause (overall) mortality was not significantly different between RP and WW groups after fifteen years of follow up (Hazard Ratio (HR) 0.9 (95% Confidence Interval (CI) 0.56 to 1.43).The second trial (N = 695), conducted in Scandinavia, was judged to be of good quality. After 12 years of follow up, the trial results were compatible with a beneficial effect of RP on the risks of overall mortality, prostate cancer mortality and distant metastases compared with WW but the precise magnitude of the effect is uncertain as indicated by the width of the confidence intervals for all estimates (risk difference (RD) -7.1% (95% CI -14.7 to 0.5); RD -5.4% (95% CI -11.1 to 0.2); RD -6.7% (95% CI -13.2 to -0.2), respectively).        Compared to WW, RP increased the absolute risks of erectile dysfunction (RD 35% (95% CI 25 to 45)) and urinary leakage (RD 27% (95% CI 17 to 37)). These estimates must be interpreted cautiously as they are derived from data obtained from a self-administered questionnaire survey of a sample of the trial participants (N = 326), no baseline quality of life data were obtained and nerve-sparing surgery was not routinely performed on trial participants undergoing RP.

AUTHORS' CONCLUSIONS

The existing trials provide insufficient evidence to allow confident statements to be made about the relative beneficial and harmful effects of RP and WW for patients with localised prostate cancer. The results of ongoing trials should help to inform treatment decisions for men with screen-detected localised prostate cancer.

Dissecting the dynamics of serum prostate-specific antigen

I have examined more than 800 values of serum prostate-specific antigen (PSA) in 119 American Veterans during the time before their diagnosis of prostate cancer. These values appear to follow an exponential model with respect to time. Specifically, the model comprises a sum of 2 exponential functions: one for an early, slowly rising component of PSA and a second for a later, faster rising component. The parameters of each component comprise an amplitude and a relative velocity. Whereas the relative velocity of the slow component is significantly associated with the volume of benign tissue, both the amplitude and relative velocity of the fast component are significantly associated with the volume of tumor. The results suggest that at the time of diagnosis of prostate cancer the level and velocity of PSA reflect the combination of slow and fast components. Thus, this model provides insight into how benign and malignant tissues in the prostate determine the dynamics of PSA.

Prostate-specific antigen kinetics in clinical decision-making during active surveillance for early prostate cancer--a review

CONTEXT

The kinetics of prostate specific antigen (PSA) are generally assumed to be indicative of tumour progression and are therefore used in clinical decision-making in men on active surveillance for early prostate cancer.

OBJECTIVE

This review aims to provide support for exploiting PSA kinetics in an active surveillance setting.

EVIDENCE ACQUISITION

We searched the Medline database and reviewed the evidence on both the relation between PSA kinetics before radical treatment for prostate cancer and outcome, as well as the role of PSA kinetics during active surveillance. Furthermore, the benefits and setbacks of different derivatives of PSA kinetics, minimum required time interval and number of measurements, practical recommendations, and pitfalls of their use in clinical practice are discussed.

EVIDENCE SYNTHESIS

The evidence concerning the prognostic value of the PSA velocity (PSA-V) and PSA doubling time (PSA-DT) is sparse, especially in active surveillance. PSA kinetics should therefore be combined with other diagnostic measures as the trigger for deferred radical treatment or repeat prostate biopsies. There seems to be consensus among several reports on the unfavourable outcome relating to a PSA-DT <3-4 yr and on the favourable prognostic value of a PSA-DT >10 yr or a decreasing PSA level. Online tools provide help with calculations and insight on disease development. The best method of calculation, number of measurements, and time interval between measurements is unknown for now.

CONCLUSIONS

Despite the current deficits in our understanding of the natural behaviour of early prostate cancer and its relation to serum PSA levels, and despite several secondary factors playing a role in PSA kinetics, PSA kinetics are a practical parameter we can offer men on active surveillance to assess the status of their disease.

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.

How much does Gleason grade of follow-up biopsy differ from that of initial biopsy in untreated, Gleason score 4-7, clinically localized prostate cancer?

OBJECTIVE

To compare histologic grades between an initial biopsy and a follow-up biopsy in untreated, Gleason score (GS) 4-7, clinically localized prostate cancer.

METHODS AND MATERIALS

In a prospective single-arm cohort study, clinically localized, GS 4-7, prostate cancer was managed with active surveillance alone, provided that a pre-defined definition of disease progression was not met. One hundred five (63%) of a total of 168 eligible patients underwent a follow-up prostate biopsy during surveillance. Median time to a follow-up biopsy was 22 months (range: 7-81). Histologic grades between these two biopsies were compared to evaluate the extent of histologic grade change.

RESULTS

On the follow-up biopsy, GS was unchanged in 33 patients (31%), upgraded in 37 (35%), and downgraded in 34 (32%). Eleven (10%) had upgrading by 2 Gleason points or more. Eight (8%) had upgrading to GS 8 (none to GS 9 or 10); of these, six were among those with upgrading by 2 Gleason points or more. Twenty-seven (26%) had no malignancy on the follow-up biopsy. Negative follow-up biopsy was more prevalent in patients with a small volume of malignancy in the initial biopsy and a low baseline PSA.

CONCLUSIONS

No consistent change in histologic grade was observed on the follow-up biopsy at a median of 22 months in untreated, GS 4-7, clinically localized prostate cancer. Upgrading to GS > or =8 or by 2 Gleason points or more was relatively uncommon.

Significance of prostate-specific antigen-doubling time on survival of patients with hormone refractory prostate cancer and bone metastasis: analysis on 56 cases of cancer-specific death

OBJECTIVE

Most of the metastatic diseases initially respond to maximum androgen blockade, but then relapse and lose response, and finally die. After relapse, the disease progresses in various courses. The present study was aimed to establish the predicting factors influencing the survival period of patients at prostate-specific antigen (PSA) relapse (entering the hormone refractory state).

MATERIALS AND METHODS

Fifty-six patients with prostate cancer and bone metastasis, who were treated during the entire disease period at the same hospital and died were studied. To calculate PSA-doubling time, assay of PSA was carried out every 3 months or less.

RESULTS

The period between PSA relapse and death was related with PSA-doubling time at relapse, nadir PSA and the period between the start of treatment and PSA relapse. The PSA-doubling time of 2 months or less at relapse was suggestive of a poor outcome. Final PSA-doubling time was not correlated with the survival period after PSA relapse.

CONCLUSION

The PSA-doubling time at relapse is one of the relevant factors for predicting the survival period after PSA relapse.

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.

Modeling Prostate Specific Antigen Kinetics in Patients on Active Surveillance

PURPOSE

Prostate specific antigen doubling time was used to stratify patients into groups at low and high risk for progression. The prostate specific antigen kinetics in these 2 groups were modeled.

MATERIALS AND METHODS

In this prospective, single-arm cohort study patients with favorable clinical parameters (stage T1b-T2b N0M0, Gleason score 7 or less, prostate specific antigen 15 ng/ml or less) were conservatively treated with watchful waiting. Evolution of serial prostate specific antigen measurements over time was estimated from a general linear mixed model of the natural log of prostate specific antigen. The corresponding average and individual prostate specific antigen doubling times were also calculated.

RESULTS

Since November 1995 a total of 231 patients had at least 6 months of followup and at least 3 prostate specific antigen measurements. Based on prostate specific antigen doubling time and repeat biopsy, 93 patients fulfilled the criteria for high risk of disease progression and 138 were defined as low risk. Given the baseline status of these individuals, 2 reference average lines (high risk and low risk) were derived to model the evolution of prostate specific antigen levels and permit more rational decision making regarding the need for definitive intervention. The average prostate specific antigen doubling time was 2.97 years (95% CI 2.2-4.4) in patients allocated to the high risk group and 6.54 years (95% CI 4.8-12.3) in those at low risk.

CONCLUSIONS

By applying the dynamic prognostic rule in combination with serial biopsy, a rational decision for definitive intervention based on the risk of disease progression could be optimally recommended about 2.3 years after initiated surveillance.

Rise in Prostate-Specific Antigen in Men with Untreated Low-Grade Prostate Cancer Is Slower During Spring-Summer

To test the hypothesis that the rate of rise in prostate-specific antigen (PSA) is slower during the spring-summer than during the rest of the year, we used PSA data from a prospective single-arm cohort study of men who had been followed to characterize a watchful observation protocol with selective delayed intervention for clinically localized, low-to-intermediate grade prostate adenocarcinoma. The rate of PSA increase was calculated as the visit-to-visit slope of log (PSA) against time, from 1 calendar-quarter visit to the next. The nonparametric Friedman test confirmed differences in rate of PSA rise among the calendar quarters (P = 0.041). Post hoc analysis showed the rate of PSA increase during Q2 was significantly slower than in each one of the other calendar quarters (Q1 versus Q2, P = 0.025; Q3 versus Q2, P = 0.002; Q4 versus Q2, P = 0.013), with no differences among quarters Q1, Q3, and Q4. These results are consistent with the vitamin D hypothesis that the higher 25-hydroxyvitamin D levels associated with spring and summer have a desirable effect on prostate biology. The therapeutic implication is that vitamin D supplementation in the range of 2000 IU/d, a dose comparable to the effect of summer, can benefit men monitored for rising PSA.

Continuing controversy over monitoring men with localized prostate cancer: a systematic review of programs in the prostate specific antigen era

PURPOSE

There is continuing controversy over the most appropriate treatment for screen detected and clinically localized prostate cancer, and increasing interest in monitoring such men initially with radical treatment targeted at cancers showing signs of progressive potential but while they are still curable. Current evidence on monitoring protocols and biomarkers used to predict disease progression was systematically reviewed.

MATERIALS AND METHODS

The MEDLINE and Excerpta Medica (EMBASE) bibliographic databases were searched from 1988 to October 2004, supplemented by manual searches of reference lists, focusing on studies reporting monitoring of men with localized prostate cancer.

RESULTS

A total of 48 potentially eligible articles were found but only 5 studies, in which there was a total of 451 participants, restricted entry criteria to men with clinically localized (T1-T2) prostate cancer. Monitoring protocols varied with little consensus, although the majority used prostate specific antigen and digital rectal examination, while some added re-biopsy to assess progression. Actuarial probabilities of freedom from disease progression at 4 to 5 years of followup were 67% to 72%. However, up to 50% of men abandoned monitoring within 2 years, largely because of anxiety related to increasing prostate specific antigen rather than objective evidence of disease progression. There was no robust evidence to support prostate specific antigen doubling times or velocity to identify men in whom disease may progress. Studies were characterized by small sample size, short-term followup, observer bias and uncertain validity around variable definitions of progression.

CONCLUSIONS

Current evidence suggests that some form of monitoring would be a suitable treatment option in men with localized prostate cancer but there is little consensus over what markers should be used in such a program or how progression should be properly defined. The search for a method that safely identifies men with prostate cancer who could avoid radical intervention must continue.

Clinical trials in patients with biochemically relapsed prostate cancer

In this section there is a wide diversity of mini-reviews, covering several areas of interest for readers. Authors from the USA write about clinical trials in patients with biochemically relapsed prostate cancer, again bridging the divide between medical oncologists and urologists who specialise in urological oncological surgery. The second paper is a joint one from Germany and the USA, bringing the reader up to date with advances in the treatment of stress urinary incontinence. Finally there are two papers from Australia describing the use of positron emission tomography in renal cancer and in prostate cancer.