Use of pretreatment prostate-specific antigen doubling time to predict outcome after radical prostatectomy

The risk of prostate cancer on incidental finding of an avid prostate uptake on 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography for non-prostate cancer-related pathology: A single centre retrospective study

Objective

To review the risk of prostate cancer (PCa) in men with incidentally reported increased intraprostatic uptake at 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) ordered at Department of Urology, The Wesley Hospital, Brisbane, QLD, Australia for non-PCa related pathology.

Methods

Retrospective analysis of consecutive men between August 2014 and August 2019 presenting to a single institution for 18F-FDG PET/CT for non-prostate related conditions was conducted. Men were classified as benign, indeterminate, or malignant depending of the results of prostate-specific antigen (PSA), PSA velocity, biopsy histopathology, and three-Tesla (3 T) multiparametric MRI (mpMRI) Prostate Imaging Reporting and Data System score, or gallium-68-prostate-specific membrane antigen (68Ga-PSMA) PET/CT results.

Results

Three percent (273/9122) of men demonstrated 18F-FDG avidity within the prostate. Eighty-five percent (231/273) were further investigated, including with PSA tests (227/231, 98.3%), 3 T mpMRI (68/231, 29.4%), 68Ga-PSMA PET/CT (33/231, 14.3%), and prostate biopsy (57/231, 24.7%). Results were considered benign in 130/231 (56.3%), indeterminate in 31/231 (13.4%), and malignant in 70/231 (30.3%). PCa was identified in 51/57 (89.5%) of the men who proceeded to biopsy, including 26/27 (96.3%) men with Prostate Imaging Reporting and Data System scores 4-5 mpMRI and six men with a positive 68Ga-PSMA PET/CT. The most common Gleason score on biopsy was greater than or equal to 4+5 (14/51, 27.5%). 68Ga-PSMA PET/CT was concordant with the 18F-FDG findings in 26/33 (78.8%). All 13 men with a positive concordant 18F-FDG, 3 T mpMRI, and 68Ga-PSMA PET/CT had PCa on biopsy. There was no statistically significant difference in the 18F-FDG maximum standardized uptake value between the benign or malignant groups (5.7 vs. 6.1; p=0.580).

Conclusion

In this study, after an incidental finding of an avid intraprostatic lesion on 18F-FDG PET/CT, 70 of the 231 cases (30.3%; 0.8% of the entire cohort) had results consistent with PCa, most commonly as Gleason score greater than or equal to 4+5 disease. Unless there is limited life expectancy due to competing medical co-morbidity, men with an incidental finding of intraprostatic uptake on 18F-FDG should be further investigated using principles of PCa detection.

Aggressive Prostate Cancer in Patients Treated with Active Surveillance

Active surveillance has emerged as a promising approach for managing low-risk and favorable intermediate-risk prostate cancer (PC), with the aim of minimizing overtreatment and maintaining the quality of life. However, concerns remain about identifying "aggressive prostate cancer" within the active surveillance cohort, which refers to cancers with a higher potential for progression. Previous studies are predictors of aggressive PC during active surveillance. To address this, a personalized risk-based follow-up approach that integrates clinical data, biomarkers, and genetic factors using risk calculators was proposed. This approach enables an efficient risk assessment and the early detection of disease progression, minimizes unnecessary interventions, and improves patient management and outcomes. As active surveillance indications expand, the importance of identifying aggressive PC through a personalized risk-based follow-up is expected to increase.

Active Surveillance for Prostate Cancer: Past, Current, and Future Trends

In response to the rising incidence of indolent, low-risk prostate cancer (PCa) due to increased prostate-specific antigen (PSA) screening in the 1990s, active surveillance (AS) emerged as a treatment modality to combat overtreatment by delaying or avoiding unnecessary definitive treatment and its associated morbidity. AS consists of regular monitoring of PSA levels, digital rectal exams, medical imaging, and prostate biopsies, so that definitive treatment is only offered when deemed necessary. This paper provides a narrative review of the evolution of AS since its inception and an overview of its current landscape and challenges. Although AS was initially only performed in a study setting, numerous studies have provided evidence for the safety and efficacy of AS which has led guidelines to recommend it as a treatment option for patients with low-risk PCa. For intermediate-risk disease, AS appears to be a viable option for those with favourable clinical characteristics. Over the years, the inclusion criteria, follow-up schedule and triggers for definitive treatment have evolved based on the results of various large AS cohorts. Given the burdensome nature of repeat biopsies, risk-based dynamic monitoring may further reduce overtreatment by avoiding repeat biopsies in selected patients.

Association between preoperative prostate-specific antigen levels and mortality in high- and intermediate-grade prostate cancer patients who received radical prostatectomy: Findings from the SEER database

Background

The degree of expression of prostate-specific antigen (PSA) has been applied for the purpose of screening and monitoring the progression of prostate cancer. The goal of this study was to evaluate the association between preoperative PSA levels and mortality outcomes in men with high- and intermediate-grade prostate cancer who received radical prostatectomy.

Methods

The 2004–2014 files of the Surveillance, Epidemiology, and End Result database were analyzed. A total of 97,357 patients with non-metastatic high- and intermediate-grade adenocarcinoma of the prostate who received radical prostatectomy were identified. Using Kaplan–Meier estimates and multivariable Cox proportional hazard models, the relationship between preoperative PSA values and cancer-specific mortality outcomes in men with high- and intermediate-grade prostate cancer who received radical prostatectomy was tested.

Results

Of 97,357 patients with high- and intermediate-grade prostate cancer who received radical prostatectomy from 2001 to 2014, there were 983 cancer-specific deaths, and the average follow-up time for the cohort was 85.0 (34.6) months. Preoperative PSA values > 10 ng/ml were associated with greater risk of cancer-specific mortality (hazard ratio 2.3, P < 0.0001) when compared to the referent/normal values for preoperative PSA (<4 ng/ml). Individuals with preoperative PSA values 4–10 ng/ml had lower risk of prostate cancer-specific mortality (hazard ratio 0.80, P = 0.03) when compared to individuals with normal preoperative PSA values.

Conclusions

Individuals with preoperative PSA values 4–10 ng/ml had 20% lower risk of prostate cancer-specific mortality when compared to individuals with preoperative PSA values of <4 ng/dl. The findings from this study suggest that low or normal preoperative PSA values may not always mean that prostate cancer is indolent, and more work needs to be done to better classify risk in men with prostate cancer.

Effect of Prior Local Treatment and Prostate-Specific Antigen Kinetics during Androgen-Deprivation Therapy on the Survival of Castration-Resistant Prostate Cancer

Prostate-specific antigen (PSA) kinetics predicts survival in castration-resistant prostate cancer (CRPC); however, the influence of prior treatment on this relationship is unclear. Patients with CRPC were stratified according to time to PSA nadir and time to CRPC progression to investigate their prognostic significance on prostate cancer-specific survival (PCSS) and whether PSA kinetics may serve as prognosticators regardless of prior local treatment. This multicenter retrospective study included 295 patients diagnosed with CRPC between September 2009 and November 2017. PSA kinetics during androgen-deprivation therapy (ADT) including %PSA decline, PSA nadir level, time to PSA nadir, and time to CRPC progression was investigated. Subgroup analysis was performed according to the prior history of local curative treatment. Patients who did not receive prior local treatment with ≥6 months to PSA nadir and <12 months to CRPC, showed lower PCSS rates than those with <6 months to PSA nadir (23.3% vs. 45.3%; p = 0.031) and ≥12 months to CRPC (20.0% vs. 47.8%; p = 0.001). In patients who had received local treatment, PSA kinetic parameters did not influence PCSS. Our results indicate that time to PSA nadir and time to CRPC progression are prognosticators of PCSS in patients with CRPC who did not previously receive curative local treatment.

Clinical significance of the prostate-specific antigen doubling time prior to and following radical prostatectomy to predict the outcome of prostate cancer

With the advent of serum prostate-specific antigen (PSA), a larger number of prostate cancers in the early phase have been successfully detected. Although decisions to perform prostate biopsies are routinely based on PSA levels, the PSA level is easily influenced by benign prostatic hyperplasia, with poor specificity. Therefore, the aim of the present study was to assess the clinical significance of prostate-specific antigen doubling time (PSADT) prior to and following radical prostatectomy. In total, 488 patients with T1c-3N0M0 prostate cancer who underwent radical prostatectomy were included. Preoperative and postoperative PSADT were retrospectively correlated with pathological and clinical outcomes. Preoperative PSADT was measured in 204 of the 488 patients. In total, 16 out of 20 patients with a preoperative PSADT of >24 months had a cancer confined to the prostate compared with 105 of 184 patients with a PSADT of <24 months. The PSA non-recurrence rate at 5 years for patients with a preoperative PSADT of >24 months was significantly better compared with those with a preoperative PSADT of <24 months (P=0.011). Patients with a PSADT of >24 months and stable PSADT were associated with PSA recurrence following surgery, based on multivariate analysis. Postoperative PSADT was measured in 51 of 111 patients with PSA failure following surgery. Pathologically, 7 of 8 patients with a post-PSADT of >24 months had a cancer confined to the prostate compared with 14 of 43 patients with a post-PSADT of <24 months. These results suggest that patients with longer preoperative PSADTs appeared to have a favorable pathological result and a higher PSA non-recurrence rate compared with those with shorter preoperative PSADTs. A longer postoperative PSADT may facilitate the observation of patients with PSA recurrence without immediate secondary treatments.

Oncological and functional outcomes 1 year after radical prostatectomy for very-low-risk prostate cancer: results from the prospective LAPPRO trial

OBJECTIVES

To analyse oncological and functional outcomes 12 months after treatment of very-low-risk prostate cancer with radical prostatectomy in men who could have been candidates for active surveillance.

PATIENTS AND METHODS

We conducted a prospective study of all men with very-low-risk prostate cancer who underwent radical prostatectomy at one of 14 participating centres. Validated patient questionnaires were collected at baseline and after 12 months by independent healthcare researchers. Biochemical recurrence (BCR) was defined as prostate-specific antigen (PSA) ≥0.25 ng/mL or treatment with salvage radiotherapy or with hormones. Urinary continence was defined as <1 pad changed per 24 h. Erectile function was defined as ability to achieve erection hard enough for penetration more than half of the time after sexual stimulation. Changes in tumour grade and stage were obtained from pathology reports. We report descriptive frequencies and proportions of men who had each outcome in various subgroups. Fisher's exact test was used to assess differences between the age groups.

RESULTS

Of the 4003 men in the LAPPRO cohort, 338 men fulfilled the preoperative national criteria for very-low-risk prostate cancer. Adverse pathology outcomes included upgrading, defined as pT3 or postoperative Gleason sum ≥7, which was present in 35% of the men (115/333) and positive surgical margins, which were present in 16% of the men (54/329). Only 2.1% of the men (7/329) had a PSA concentration >0.1 ng/mL 6-12 weeks postoperatively. Erectile function and urinary continence were observed in 44% (98/222) and 84% of the men (264/315), respectively, 12 months postoperatively. The proportion of men achieving the trifecta, defined as preoperative potent and continent men who remained potent and continent with no BCR, was 38% (84/221 men) at 12 months.

CONCLUSIONS

Our prospective study of men with very-low-risk prostate cancer undergoing open or robot-assisted radical prostatectomy showed that there were favourable oncological outcomes in approximately two-thirds. Approximately 40% did not have surgically induced urinary incontinence or erectile dysfunction 12 months postoperatively. These results provide additional support for the use of active surveillance in men with very-low-risk prostate cancer; however, the number of men with risk of upgrading and upstaging is not negligible. Improved stratification is still urgently needed.

Preoperative CA 19-9 kinetics as a prognostic variable in radiographically resectable pancreatic adenocarcinoma

BACKGROUND AND OBJECTIVES

Serial levels of CA 19-9 are correlated with treatment response and survival; however, little is known about CA 19-9 kinetics in the absence of therapy. We hypothesize that preoperative CA 19-9 kinetics predict rate of resectability as well as survival.

METHODS

Retrospective review of 72 patients with radiographically resectable pancreatic adenocarcinoma with two pre-operative CA 19-9 levels prior to planned pancreaticoduodenectomy. Primary outcome measures were resectability and overall survival.

RESULTS

Forty-seven out of 72 patients (65%) had resectable disease. Unresectable patients had higher absolute change in CA 19-9 than patients with resectable disease (97 U/ml vs. -34 U/ml) as well as higher rate of change (4 U/ml/day vs. -1 U/ml/day). Receiver operating characteristic curves identified predictive thresholds for absolute (≥50 U/ml) and rate of CA 19-9 change (≥1 U/ml/day) that accurately identified unresectable patients. Survival analysis revealed that a change in CA 19-9 <50 U/ml and a rate of change <1 U/ml/day predicted improved survival (P = 0.04, P = 0.02); however, for patients with resectable disease, CA 19-9 changes did not predict survival.

CONCLUSIONS

Preoperative kinetics of CA 19-9 predict resectable disease for pancreatic cancer. These variables also predict overall survival; however, these do not predict survival for those with resectable disease.

Evaluation of prediagnostic prostate-specific antigen dynamics as predictors of death from prostate cancer in patients treated conservatively

Prostate-specific antigen (PSA) dynamics have been proposed to predict outcome in men with prostate cancer. We assessed the value of PSA velocity (PSAV) and PSA doubling time (PSADT) for predicting prostate cancer-specific mortality (PCSM) in men with clinically localized prostate cancer undergoing conservative management or early hormonal therapy. From 1990 to 1996, 2,333 patients were identified, of whom 594 had two or more PSA values before diagnosis. We examined 12 definitions for PSADT and 10 for PSAV. Because each definition required PSA measurements at particular intervals, the number of patients eligible for each definition varied from 40 to 594 and number of events from 10 to 119. Four PSAV definitions, but no PSADT, were significantly associated with PCSM after adjustment for PSA in multivariable Cox proportional hazards regression. All four could be calculated only for a proportion of events, and the enhancements in predictive accuracy associated with PSAV had very wide confidence intervals. There was no clear benefit of PSAV in men with low PSA and Gleason grade 6 or less. Although evidence that certain PSAV definitions help to predict PCSM in the cohort exist, the value of incorporating PSAV in predictive models to assist in determining eligibility for conservative management is, at best, uncertain.

Tumor regression and growth rates determined in five intramural NCI prostate cancer trials: the growth rate constant as an indicator of therapeutic efficacy

PURPOSE

In solid tumors such as prostate cancer, novel paradigms are needed to assess therapeutic efficacy. We utilized a method estimating tumor growth and regression rate constants from serial PSA measurements, and assessed its potential in patients with metastatic castration resistant prostate carcinoma (mCRPC).

EXPERIMENTAL DESIGN

Patients were enrolled in five phase II studies, including an experimental vaccine trial, representing the evolution of therapy in mCRPC. PSA measurements obtained before, and during, therapy were used. Data analysis using a two-phase mathematical equation yielded concomitant PSA growth and regression rate constants.

RESULTS

Growth rate constants (g) can be estimated while patients receive therapy and in such patients g is superior to PSA-DT in predicting OS. Incremental reductions in growth rate constants were recorded in successive trials with a 10-fold slower g in the most recent combination therapy trial (log g = 10(-3.17)) relative to single-agent thalidomide (log g = 10(-2.08)) more than a decade earlier. Growth rate constants correlated with survival, except in patients receiving vaccine-based therapy where the evidence demonstrates prolonged survival presumably due to immunity developing subsequent to vaccine administration.

CONCLUSION

Incremental reductions in tumor growth rate constants suggest increased efficacy in successive chemotherapy trials. The derived growth rate constant correlates with survival, and may be used to assess efficacy. The PSA-TRICOM vaccine appears to have provided marked benefit not apparent during vaccination, but consistent with subsequent development of a beneficial immune response. If validated as a surrogate for survival, growth rate constants would offer an important new efficacy endpoint for clinical trials.

Screening, risk assessment, and the approach to therapy in patients with prostate cancer

The major challenge in prostate cancer is to identify patients at higher risk of death and to distinguish them from those more likely to die from other causes. Stratification of patients into risk groups can be used to guide management decisions at each disease stage. This review discusses the measures, tools, and nomograms available for risk assessment in prostate cancer. For patients with localized hormone-sensitive disease, the choice is between active surveillance and radical treatment, with focal therapy an emerging option. Current guidelines recommend treatment of patients with a life expectancy ≥10 years, although active surveillance is being used with increasing frequency for low-risk patients, even with a long life expectancy. A number of risk stratification methods have been devised to assess the risk of biochemical recurrence (BCR) after treatment, with prostate-specific antigen (PSA) level, Gleason score, clinical stage, and tumor mass/volume all shown to be predictive of BCR. Among men with BCR after treatment, PSA doubling time (PSADT) was the best predictor of further progression. Although studies in patients with castration-resistant prostate cancer have shown that PSA level and PSADT are associated with a risk of developing metastatic disease, there is currently no clear surrogate for disease progression or overall survival for this patient group and no standard second- or third-line therapy after progression on first-line chemotherapy. The use of newly developed risk-stratification models and markers of disease progression should assist in the earlier identification of disease progression, allowing the optimal treatment of such patients.

Other paradigms: growth rate constants and tumor burden determined using computed tomography data correlate strongly with the overall survival of patients with renal cell carcinoma

In solid tumors, where curative therapies still elude oncologists, novel paradigms are needed to assess the efficacy of new therapies and those already approved. We used radiologic measurements obtained in patients with metastatic renal cell carcinoma enrolled in a phase II study of the epothilone B analog, ixabepilone (Ixempra), to address this issue. Using a novel 2-phase mathematical equation, we used the radiologic measurements to estimate the concomitant rates of tumor regression and growth (regression and growth rate constants). Eighty-one patients were enrolled on the ixabepilone trial at the time of this analysis. Growth rate constants were determined using computed tomography measurements obtained exclusively while a patient was enrolled on study. The growth rate constants of renal cell carcinomas treated with ixabepilone were significantly reduced compared with those of tumors in patients who received placebo in a previous trial. Furthermore, a correlation with overall survival was found for both the growth rate constant and the initial tumor burden; and this correlation was even stronger when both the growth rate constant and the initial tumor burden were combined. The readily amenable mathematical model described herein has potential applications to many tumor types that can be assessed with imaging modalities. Because the growth rate constant seems to be a surrogate for survival, assessment could aid in the evaluation of relative efficacies of different therapies and perhaps in assessing the potential individual benefit of an experimental therapy.

Pretreatment prostate-specific antigen (PSA) velocity and doubling time are associated with outcome but neither improves prediction of outcome beyond pretreatment PSA alone in patients treated with radical prostatectomy

PURPOSE

Controversy exists as to whether current pretreatment prostate-specific antigen (PSA) dynamics enhance outcome prediction in patients undergoing treatment for prostate cancer. We assessed whether pretreatment PSA velocity (PSAV) or doubling time (PSADT) predicted outcome in men undergoing radical prostatectomy and whether any definition enhanced accuracy of an outcome prediction model.

PATIENTS AND METHODS

The cohort included 2,938 patients with two or more PSA values before radical prostatectomy. Biochemical recurrence (BCR) occurred in 384 patients, and metastases occurred in 63 patients. Median follow-up for patients without BCR was 2.1 years. We used univariate Cox proportional hazards regression to evaluate associations between published definitions of PSADT and PSAV with BCR and metastasis. Predictive accuracy was assessed using the concordance index.

RESULTS

On univariate analysis, two of 12 PSADT and four of 10 PSAV definitions were univariately associated with both BCR and metastasis (P < .05). One PSADT and one PSAV definition had a higher predictive accuracy for BCR over PSA alone, and four PSAV definitions improved prediction of metastasis. However, the improvements in predictive accuracy were small, associated with wide CIs, and markedly reduced if additional predictors of stage and grade were included alongside PSA. Modeling with random variables suggests that similar results would be expected by chance. CONCLUSION We found no clear evidence that any definition of PSA dynamics substantially enhances the predictive accuracy of a single pretreatment PSA alone.

What is the best approach for screen-detected low volume cancers?--The case for observation

The case for active surveillance as the optimal therapy for screen detected, low volume, low grade prostate cancer is presented. This is based on data from recent long term studies of conservative management, the prostate cancer prevention trial (PCPT), the Swedish trial of radical prostatectomy vs. observation, and several large Phase 2 trials of active surveillance. These studies indicate convincingly that (1) widespread screening results in a diagnosis of prostate cancer in many patients with clinical insignificant disease, (2) that these patients can be identified with reasonable accuracy, (3) that delayed intervention does not appear to put those patients who reclassify as higher risk over time at significant risk, and (4) that the psychological burden of surveillance is acceptable.

Tumor growth rates derived from data for patients in a clinical trial correlate strongly with patient survival: a novel strategy for evaluation of clinical trial data

PURPOSE

The slow progress in developing new cancer therapies can be attributed in part to the long time spent in clinical development. To hasten development, new paradigms especially applicable to patients with metastatic disease are needed.

PATIENTS AND METHODS

We present a new method to predict survival using tumor measurement data gathered while a patient with cancer is receiving therapy in a clinical trial. We developed a two-phase equation to estimate the concomitant rates of tumor regression (regression rate constant d) and tumor growth (growth rate constant g).

RESULTS

We evaluated the model against serial levels of prostate-specific antigen (PSA) in 112 patients undergoing treatment for prostate cancer. Survival was strongly correlated with the log of the growth rate constant, log(g) (Pearson r = -0.72) but not with the log of the regression rate constants, log(d) (r = -0.218). Values of log(g) exhibited a bimodal distribution. Patients with log(g) values above the median had a mortality hazard of 5.14 (95% confidence interval, 3.10-8.52) when compared with those with log(g) values below the median. Mathematically, the minimum PSA value (nadir) and the time to this minimum are determined by the kinetic parameters d and g, and can be viewed as surrogates.

CONCLUSIONS

This mathematical model has applications to many tumor types and may aid in evaluating patient outcomes. Modeling tumor progression using data gathered while patients are on study, may help evaluate the ability of therapies to prolong survival and assist in drug development.

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.

Long-term prediction of prostate cancer: prostate-specific antigen (PSA) velocity is predictive but does not improve the predictive accuracy of a single PSA measurement 15 years or more before cancer diagnosis in a large, representative, unscreened population

PURPOSE

We tested whether total prostate-specific antigen velocity (tPSAv) improves accuracy of a model using PSA level to predict long-term risk of prostate cancer diagnosis.

METHODS

During 1974 to 1986 in a preventive medicine study in Sweden, 5,722 men aged <or= 50 gave two blood samples about 6 years apart. We measured free (fPSA) and total PSA (tPSA) in archived plasma samples from 4,907 participants. Prostate cancer was subsequently diagnosed in 443 (9%) men. Cox proportional hazards regression was used to evaluate tPSA and tPSAv as predictors of prostate cancer. Predictive accuracy was assessed by the concordance index.

RESULTS

The median time from second blood draw to cancer diagnosis was 16 years; median follow-up for men without prostate cancer was 21 years. In univariate models, tPSA level at second assessment and tPSAv between first and second assessments were associated with prostate cancer (both P < .001). tPSAv was highly correlated with tPSA level (r = 0.93). Twenty-year probabilities of cancer for men at 50th, 90th, and 95th percentile of tPSA and tPSAv were 10.6%, 17.1%, and 21.2% for tPSA, and 9.1%, 11.8%, and 14.1% for tPSAv, respectively. The concordance index for tPSA level was 0.771. Adding tPSAv, fPSA, %fPSA or velocities of fPSA and %fPSA did not importantly increase accuracy of tPSA to predict prostate cancer. Results were unchanged if the analysis was restricted to patients with advanced cancer at diagnosis.

CONCLUSION

Although PSA velocity is significantly increased in men with prostate cancer up to two decades before diagnosis, it does not aid long-term prediction of prostate cancer.

Active surveillance for favorable-risk prostate cancer: who, how and why?

Active surveillance for favorable-risk prostate cancer has become increasingly common in populations in which screening for prostate cancer is widespread, owing to evidence that in many patients screening results in the detection of disease that is not clinically significant (i.e. untreated, it would not pose a threat to health). The approach is supported by data demonstrating that patients who have clinically insignificant disease can be identified with reasonable accuracy, and that patients who are initially classified as low risk but reclassified over time as higher risk and are treated radically are still cured in most cases. It is important to identify patients who have a low probability of disease progression during their lifetime according to clinical and pathologic features of the disease, patient age and comorbidity. Close monitoring of patients over time and availability of reasonable criteria for intervention, which will both identify more-aggressive disease in a timely fashion and not result in excessive treatment, are crucial. It is also important to communicate appropriately with the patient, to reduce the psychological burden of living with untreated cancer. The results of active surveillance, the criteria for patient selection and the appropriate thresholds for intervention are reviewed in this article.

Active surveillance versus radical treatment for favorable-risk localized prostate cancer

Widespread prostate-specific antigen (PSA) screening in North America has resulted in a profound stage migration and a marked increase in incidence. One in six men is now diagnosed, many with small-volume, low-grade cancer. This incidence is dramatically higher than the 3% lifetime risk of prostate cancer death that characterized the pre-screening era. This article summarizes the case for active surveillance for "favorable-risk" prostate cancer with selective delayed intervention for rapid biochemical progression, assessed by increasing PSA levels, or grade progression. The results of a large phase II trial using this approach are reviewed. To date, this study has shown that virtually all men with favorable-risk prostate cancer managed in this fashion will die of unrelated causes. Based on the Swedish randomized trial of radical prostatectomy versus watchful waiting, the Connecticut observation series, and the Toronto active surveillance experience, a number needed to treat analysis of the benefit of radical treatment of all newly diagnosed favorable-risk prostate cancer patients, compared with a strategy of active surveillance with selective delayed intervention, is presented. This suggests that approximately 73 patients will require radical treatment for each prostate cancer death averted. This translates into a 3- to 4-week survival benefit, unadjusted for quality of life. This figure is confirmed based on an analysis of the 2004 D'Amico et al. PSA velocity data in favorable-risk disease. The approach of active surveillance with selective delayed intervention based on PSA doubling time and repeat biopsy represents a practical compromise between radical therapy for all patients (which results in overtreatment for patients with indolent disease) and watchful waiting with palliative therapy only (which results in undertreatment for those with aggressive disease).

Detection of life-threatening prostate cancer with prostate-specific antigen velocity during a window of curability

BACKGROUND

Prostate-specific antigen (PSA) level is typically used as a dichotomous test for prostate cancer, resulting in overdiagnosis for a substantial number of men. The rate at which serum PSA levels change (PSA velocity) may be an important indicator of the presence of life-threatening disease.

METHODS

PSA velocity was determined in 980 men (856 without prostate cancer, 104 with prostate cancer who were alive or died of another cause, and 20 who died of prostate cancer) who were participants in the Baltimore Longitudinal Study of Aging for up to 39 years. The relative risks (RRs) of prostate cancer death and prostate cancer-specific survival stratified by PSA velocity were evaluated in the three groups of men by Cox regression and Kaplan-Meier analyses. Statistical tests were two-sided.

RESULTS

PSA velocity measured 10-15 years before diagnosis (when most men had PSA levels below 4.0 ng/mL) was associated with cancer-specific survival 25 years later; survival was 92% (95% confidence interval [CI] = 84% to 96%) among men with PSA velocity of 0.35 ng/mL per year or less and 54% (95% CI = 15% to 82%) among men with PSA velocity above 0.35 ng/mL per year (P<.001). Furthermore, men with PSA velocity above 0.35 ng/mL per year had a higher relative risk of prostate cancer death than men with PSA velocity of 0.35 ng/mL per year or less (RR = 4.7, 95% CI = 1.3 to 16.5; P = .02); the rates per 100,000 person-years were 1240 for men with a PSA velocity above 0.35 ng/mL per year and 140 for men with a PSA velocity of 0.35 ng/mL per year or less.

CONCLUSIONS

PSA velocity may help identify men with life-threatening prostate cancer during a period when their PSA levels are associated with the presence of curable disease.

Preoperative prostate specific antigen doubling time and velocity are strong and independent predictors of outcomes following radical prostatectomy

PURPOSE

Prostate specific antigen (PSA) is a useful marker for predicting outcomes following treatment for prostate cancer but, given the evolving nature of prostate cancer, there is an ongoing need to refine its use. We assessed preoperative PSA doubling time (PSADT) and PSA velocity (PSAV) as predictors of outcome following radical retropubic prostatectomy (RRP).

MATERIALS AND METHODS

We identified 2,290 men who were treated with RRP for prostate cancer between 1990 and 1999 with multiple preoperative PSA measurements available. PSADT was calculated by log linear regression and PSAV was calculated by linear regression. These parameters were used in preoperative and postoperative multivariate models for the end points of biochemical and clinical progression, and cancer death.

RESULTS

At a median followup of 7.1 years (range 0.1 to 14.5) biochemical progression, clinical progression and death from prostate cancer were observed in 583, 156 and 42 patients, respectively. The HR for death from prostate cancer was 6.22 (95% CI 3.33 to 11.61) in men with PSADT less than 18 months vs 18 or greater and 6.54 (95% CI 3.51 to 12.19) in men with PSAV greater than 3.4 ng/ml yearly vs 3.4 or less. On multivariate analysis adjusting for preoperative or postoperative variables PSADT and PSAV remained significant predictors of each outcome. When assessed jointly, PSAV was significant as a predictor of biochemical progression, while PSADT was a significant predictor of clinical progression and cancer death.

CONCLUSIONS

This study confirms the usefulness of preoperative PSA kinetics for predicting post-RRP outcomes, which may be useful for stratifying patients, so that rational management decisions can be made with respect to observation, intervention and adjuvant treatment. While PSADT maybe biologically more accurate and stronger on multivariate analysis, PSAV is clinically easier to use and a good approximation in the short term.

Prostate-specific antigen doubling time as a prognostic marker in prostate cancer

Prostate cancer has a varied natural history. Men with similar serum prostate-specific antigen (PSA) levels, clinical stages, and histologic features in their tissue specimens can have markedly different outcomes. While prostate cancer is lethal in some patients, most men die with cancer rather than because of it. Moreover, histologically apparent cancer can be found in the prostate glands of approximately 42% of men over 50 years of age who die from other causes, but the lifetime risk that a man in the US will be diagnosed with prostate cancer is estimated to be 11% and the risk of dying from the disease is only 3.1%. Consequently, appropriate disease management requires risk assessment. How likely is it that a given man's cancer will progress or metastasize over his remaining lifetime? What is the probability of successful treatment? What are the risks of adverse effects and complications of each treatment? Physicians use a variety of clinical and pathologic parameters to assess the risk that a given cancer poses to an individual patient. In addition to the accepted parameters of serum PSA level, clinical staging, and pathologic grading and staging, PSA doubling time has emerged as an important factor in the evaluation of men with newly diagnosed prostate cancer or prostate cancer that recurs after treatment. PSA doubling time can also be used as a surrogate marker for prostate cancer-specific death. This review summarizes current knowledge regarding the role of PSA doubling time as a prognostic marker in men with prostate cancer.

Preoperative PSA velocity is an independent prognostic factor for relapse after radical prostatectomy

PURPOSE

Preoperative prostate-specific antigen (PSA) velocity (PSAV), or the rate of PSA rise before diagnosis, predicts for risk of cancer death after radical prostatectomy (RP). We evaluated the relative merit of established preoperative factors, including biopsy indices and preoperative PSAV, for their impact on relapse after RP.

PATIENTS AND METHODS

The outcomes of 202 men who underwent RP were reviewed. Biopsies were characterized for grade, percentage positive cores, and total linear tumor length. Surgical specimens were characterized for cancer volume, relative percentage by grade, extracapsular extension, and margin status. Univariate and multivariate analyses were performed with respect to relapse-free survival after RP.

RESULTS

Thirty-one patients relapsed after RP (defined as PSA > or = 0.2 ng/mL), with a median time to failure of 16 months. Median follow-up was 48 months. Kaplan-Meier relapse-free survival at 5 years was 89%, compared with 73% for PSAV < or = 2 v > 2 ng/mL/year (P = .003). On multivariate analysis, only the biopsy Gleason sum (P < .008; relative risk, > 4.8) and the preoperative PSAV (P < .04; relative risk, 3.0 to 4.7) remained significant. Patients with a PSAV of > 2 ng/mL/year were more likely to be pT3 (P = .007), have positive margins (P = .01), have tumors > 1 mL (P = .05), and possess > 10% grade 4/5 tumors (P = .04).

CONCLUSION

The preoperative PSAV is a significant independent clinical factor predicting for relapse after RP and also predicts for larger, more aggressive, and more locally advanced tumors. Its inclusion will be useful in risk stratification, evaluation for alternatives to surgery, and patient selection for neoadjuvant or adjuvant therapies as part of randomized clinical trials.

Biomarkers for the detection and prognosis of prostate cancer

Recent studies have cast doubt on the reliability of serum total prostate-specific antigen as a biomarker for the detection and prognosis of prostate cancer. Biomarkers that can identify those men at risk for clinically significant prostate cancer are desperately needed. The search for biomarkers that may improve the detection of biologically consequential prostate cancer is one of the most active areas under current investigation. In this review, we highlight some of these ongoing efforts. Proper validation of newly discovered biomarkers is of paramount importance.

Active surveillance with selective delayed intervention is the way to manage 'good-risk' prostate cancer

This review summarizes the case for active surveillance of 'good-risk' prostate cancer, with selective delayed intervention for rapid biochemical progression, assessed by rising prostate-specific antigen (PSA) levels or grade progression. The results of a large phase II trial using this approach are also reviewed. A prospective phase II study of active surveillance with selective delayed intervention was initiated in 1995. Patients were managed initially with surveillance; those who had a PSA doubling time (PSADT) of < or = 2 years, or grade progression on repeat biopsy, were offered radical intervention. The remaining patients were closely monitored. The cohort now consists of 299 patients with good-risk--or, in men over 70 years of age, intermediate-risk--prostate cancer. The median PSADT was 7 years, 42% had a PSADT > 10 years. The majority of patients remain on surveillance. At 8 years, overall actuarial survival was 85%, and disease-specific survival was 99%. To date, this study has shown that most men with 'good-risk' prostate cancer will die of unrelated causes. The approach of active surveillance with selective delayed intervention based on PSADT represents a practical compromise between radical therapy for all patients, which results in overtreatment for patients with indolent disease, and watchful waiting with palliative therapy only, which results in undertreatment for those with aggressive disease. The results at 8 years were favorable. Longer follow-up will be required if the study is to confirm the safety of this approach in men with a long life expectancy (> 15 years).

Prostate-specific antigen doubling time among Japanese men in an annual health screening program

BACKGROUND

Prostate-specific antigen doubling time (PSA-DT) has been studied as a parameter reflecting the biological doubling rate of clinically localized prostate cancer treated expectantly. With the use of PSA-DT, we studied the natural history of PSA changes among Japanese men in a health screening program.

METHODS

Between July 1994 and December 2002, a cohort of 1995 men aged 40-79 years underwent a total of 5700 PSA measurements in an annual multiphasic health screening program. Prostate-specific antigen doubling time was calculated using a log-linear regression model for 994 (49.8%) men who had three or more serial PSA measurements with a mean follow-up of 46.2 months.

RESULTS

Of the 994 men, 192 (19.3%) had a PSA-DT of less than 10 years and 12 (1.2%) had a PSA-DT of less than 2 years. Median PSA-DT in 14 men with a subsequent diagnosis of prostate cancer was 41.6 months (range, 12.2 to stable). A log-linear model statistically fitted 65 of 180 non-cancer patients with a PSA-DT of less than 10 years. The percentages of statistically fit cases increased with higher baseline PSA (5.3%, 7.7% and 8.7% among men with <1.0, 1.0-1.99 and 2.0-3.99 ng/mL, respectively) and older baseline age (3.7%, 8.5% and 6.9% among ages 40-49, 50-59 and 60 or older, respectively).

CONCLUSION

In a small but significant portion of men, PSA increases exponentially when it is still less than 4.0 ng/mL, with a PSA-DT of less than 10 years. The clinical significance of this finding should be evaluated by a prospective screening including biopsy.

Preoperative PSA velocity and the risk of death from prostate cancer after radical prostatectomy

BACKGROUND

We evaluated whether men at risk for death from prostate cancer after radical prostatectomy can be identified using information available at diagnosis.

METHODS

We studied 1095 men with localized prostate cancer to assess whether the rate of rise in the prostate-specific antigen (PSA) level--the PSA velocity--during the year before diagnosis, the PSA level at diagnosis, the Gleason score, and the clinical tumor stage could predict the time to death from prostate cancer and death from any cause after radical prostatectomy.

RESULTS

As compared with an annual PSA velocity of 2.0 ng per milliliter or less, an annual PSA velocity of more than 2.0 ng per milliliter was associated with a significantly shorter time to death from prostate cancer (P<0.001) and death from any cause (P=0.01). An increasing PSA level at diagnosis (P=0.01), a Gleason score of 8, 9, or 10 (P=0.02), and a clinical tumor stage of T2 (P<0.001) also predicted the time to death from prostate cancer. For men with an annual PSA velocity of more than 2.0 ng per milliliter, estimates of the risk of death from prostate cancer and death from any cause seven years after radical prostatectomy were also influenced by the PSA level, tumor stage, and Gleason score at diagnosis.

CONCLUSIONS

Men whose PSA level increases by more than 2.0 ng per milliliter during the year before the diagnosis of prostate cancer may have a relatively high risk of death from prostate cancer despite undergoing radical prostatectomy.