Pretreatment prostate-specific antigen doubling times: clinical utility of this predictor of prostate cancer behavior

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.

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.

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

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

Genome abnormalities precede prostate cancer and predict clinical relapse

The prediction of prostate cancer clinical outcome remains a major challenge after the diagnosis, even with improved early detection by prostate-specific antigen (PSA) monitoring. To evaluate whether copy number variation (CNV) of the genomes in prostate cancer tumor, in benign prostate tissues adjacent to the tumor (AT), and in the blood of patients with prostate cancer predicts biochemical (PSA) relapse and the kinetics of relapse, 241 samples (104 tumor, 49 matched AT, 85 matched blood, and 3 cell lines) were analyzed using Affymetrix SNP 6.0 chips. By using gene-specific CNV from tumor, the genome model correctly predicted 73% (receiver operating characteristic P = 0.003) cases for relapse and 75% (P < 0.001) cases for short PSA doubling time (PSADT, <4 months). The gene-specific CNV model from AT correctly predicted 67% (P = 0.041) cases for relapse and 77% (P = 0.015) cases for short PSADT. By using median-sized CNV from blood, the genome model correctly predicted 81% (P < 0.001) cases for relapse and 69% (P = 0.001) cases for short PSADT. By using median-sized CNV from tumor, the genome model correctly predicted 75% (P < 0.001) cases for relapse and 80% (P < 0.001) cases for short PSADT. For the first time, our analysis indicates that genomic abnormalities in either benign or malignant tissues are predictive of the clinical outcome of a malignancy.

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.

Treatment strategies for high-risk locally advanced prostate cancer

High-risk prostate cancer can be defined by the assessment of pretreatment prognostic factors such as clinical stage, Gleason score, and PSA level. High-risk features include PSA >20 ng/ml, Gleason score 8-10, and stage T3 tumors. Patients with adverse prognostic factors have historically fared poorly with monotherapeutic approaches. Multimodal treatment utilizing combined androgen suppression and radiotherapy has improved survival rates for patients with high-risk prostate cancer. In addition, multiple randomized trials in patients treated with primary radical prostatectomy have demonstrated improved outcomes with the addition of adjuvant radiotherapy. Improved radiotherapy techniques that allow for dose escalation, and new systemic therapy approaches such as adjuvant chemotherapy, present promising future therapeutic alternatives for patients with high-risk prostate cancer.

Prostate-specific antigen halving time while on neoadjuvant androgen deprivation therapy is associated with biochemical control in men treated with radiation therapy for localized prostate cancer

PURPOSE

To assess whether the PSA response to neoadjuvant androgen deprivation therapy (ADT) is associated with biochemical control in men treated with radiation therapy (RT) for prostate cancer.

METHODS AND MATERIALS

In a cohort of men treated with curative-intent RT for localized prostate cancer between 1988 and 2005, 117 men had PSA values after the first and second months of neoadjuvant ADT. Most men had intermediate-risk (45%) or high-risk (44%) disease. PSA halving time (PSAHT) was calculated by first order kinetics. Median RT dose was 76 Gy and median total duration of ADT was 4 months. Freedom from biochemical failure (FFBF, nadir + 2 definition) was analyzed by PSAHT and absolute PSA nadir before the start of RT.

RESULTS

Median follow-up was 45 months. Four-year FFBF was 89%. Median PSAHT was 2 weeks. A faster PSA decline (PSAHT ≤2 weeks) was associated with greater FFBF (96% vs. 81% for a PSAHT >2 weeks, p = 0.0110). Those within the fastest quartile of PSAHTs (≤ 10 days) achieved a FFBF of 100%. Among high-risk patients, a PSAHT ≤2 weeks achieved a 4-yr FFBF of 93% vs. 70% for those with PSAHT >2 weeks (p = 0.0508). Absolute PSA nadir was not associated with FFBF. On multivariable analysis, PSAHT (p = 0.0093) and Gleason score (p = 0.0320) were associated with FFBF, whereas T-stage (p = 0.7363) and initial PSA level (p = 0.9614) were not.

CONCLUSIONS

For men treated with combined ADT and RT, PSA response to the first month of ADT may be a useful criterion for prognosis and treatment modification.

Preoperative prostate specific antigen doubling time is not a useful predictor of biochemical progression after radical prostatectomy

PURPOSE

Postoperative prostate specific antigen doubling time may be used as a surrogate for prostate cancer specific mortality in patients with biochemical recurrence after radical prostatectomy. Less is known about the usefulness of preoperative prostate specific antigen doubling time for the initial prediction of prostatectomy outcomes.

MATERIALS AND METHODS

Preoperative prostate specific antigen doubling time was calculated in 1,208 men from a large prostate cancer screening study who were treated with radical prostatectomy. We examined the relationship of prostate specific antigen doubling time with tumor features and biochemical progression-free survival.

RESULTS

Overall prostate specific antigen doubling time was associated with nonorgan confined disease (OR 0.996, 95% CI 0.992-0.999, p = 0.013) but not with biochemical progression (HR 1.000, 95% CI 0.998-1.001, p = 0.66). Using previously published 18 and 36-month thresholds for prostate specific antigen doubling time there was no significant relationship between doubling time and specific adverse pathological features or biochemical progression. Using the concordance index prostate specific antigen doubling time did not enhance the prediction of biochemical progression beyond that achieved by a model with prostate specific antigen, clinical stage and biopsy Gleason score.

CONCLUSIONS

In our series of men with newly diagnosed, clinically localized prostate cancer shorter preoperative prostate specific antigen doubling time was associated with nonorgan confined disease but not with biochemical progression after radical prostatectomy. All calculations of prostate specific antigen kinetics may not be equivalent. Caution should be exercised when using prostate specific antigen doubling time in the pretreatment setting.

Hypermethylation of genes for diagnosis and risk stratification of prostate cancer

To identify the relevant CpG sites as molecular markers, for the diagnosis and to distinguish the indolent and aggressive prostate tumors, we have determined the methylation status of 8 genes, including FLNC, EFS, ECRG4, RARB2, PITX2, GSTP1, PDLIM4, and KCNMA1 in 32 nonrecurrent, 32 recurrent primary prostate tumors, and 32 benign prostate tissues using EpiTYPER technology. Specific CpG site hypermethylation of RARB2 and GSTP1 CpG sites were useful for diagnosis of prostate cancer. Furthermore, CpG site hypermethylation of genes FLNC, EFS, ECRG4, PITX2, PDLIM4, and KCNMA1 were associated with prediction of biochemical, local, and systemic recurrence of prostate cancer.

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.

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.

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.

Predicting biochemical failure and overall survival through intratherapy PSA changes during definitive external beam radiotherapy

PURPOSE

To determine whether intratherapy prostate-specific antigen (itPSA) changes during radiotherapy (RT) predict prostate cancer outcomes.

METHODS AND MATERIALS

We retrospectively identified patients treated with definitive external beam RT without hormonal therapy who had at least two itPSA measurements. We calculated the adjusted ratio of rise (ARR) in itPSA relative to the pretreatment baseline PSA for each patient. This was defined as ln(maximal itPSA + 1)/ln(baseline PSA + 1). We stratified patients according to an ARR of <1 vs. >1.1. This corresponded to an approximately <30% vs. >30% increase in PSA during RT. Univariate and multivariate analyses were performed examining for biochemical failure-free survival (BFFS) and overall survival (OS).

RESULTS

At a median follow-up of 74 months, we identified 307 patients who met our criteria. Univariate analysis revealed that patients with an ARR of <1.1 (n = 182) had statistically significant inferior BFFS and OS compared with those with an ARR of >1.1 (n = 125). The median BFFS and OS for these two groups was 51 vs. 101 months (p = 0.001) and 96 vs. 128 months (p = 0.01), respectively. On multivariate analysis, the effect of ARR on the risk of biochemical failure for patients with an ARR of <1.1 was significant (p = 0.03) only during the first year after RT. In contrast, the effect of the ARR on OS remained significant for a full 5 years (p = 0.05).

CONCLUSION

The results of our study have shown that an ARR of <1.1 predicts for inferior BFFS and OS in patients treated with RT alone. PSA measurement during RT is a novel clinical tool that could be used to identify patients who might warrant more aggressive therapeutic intervention.

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.

Prostate specific antigen kinetics in the management of prostate cancer

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Prostate-specific antigen doubling time before onset of chemotherapy as a predictor of survival for hormone-refractory prostate cancer patients

BACKGROUND

We evaluated the possible use of prostate-specific antigen doubling time (PSA-DT) before chemotherapy initiation as a surrogate marker of survival in hormone-refractory prostate cancer (HRPC) patients.

PATIENTS AND METHODS

Data from 250 consecutive metastatic HRPC patients treated with chemotherapy between February 2000 and November 2006 were retrospectively analysed. At least three PSA assays were required within 3 months before chemotherapy. PSA-DT was calculated as ln 2 divided by the slope of the log PSA line, and the difference between two log PSA levels was divided by the time interval. The primary endpoint was overall survival (OS). Survival rates according to PSA-DT were stratified on chemotherapy regimen. Multivariate Cox regression analysis was performed to isolate the impact of PSA-DT on OS, controlling for associate prognostic covariates.

RESULTS

Patients received docetaxel- (82%) or mitoxantrone-based chemotherapy. The median PSA-DT was 45 days (range 4.7-1108 days). There were 174 deaths (70%). The median survival was 16.5 months (95% confidence interval [CI] = 12.5-20.5) and 26.4 months (95% CI = 20.3-32.4) for patients with a PSA-DT < 45 and > or =45 days, respectively. In the multivariate setting, the adjusted hazard ratio (HR) was 1.39 (95% CI = 1.03-1.89; P = 0.04), stratified by chemotherapy regimen.

CONCLUSION

A short PSA-DT before onset of chemotherapy in HRPC patients was associated with an increased risk of death. This could be useful as a stratification parameter in trials with new drugs in a metastatic setting.

Distinct Prognostic Role of Prostate-Specific Antigen Doubling Time and Velocity at Emergence of Androgen Independence in Patients Treated with Chemotherapy

OBJECTIVES

To investigate whether the prostate-specific antigen doubling time (PSADT) and velocity (PSAV) at the emergence of androgen-independent prostate cancer (AIPC) provide independent prognostic information.

METHODS

Patients treated with chemotherapy were identified in an institutional prostate cancer database. The PSADT was calculated using PSA values from the first increase greater than the PSA nadir during androgen deprivation therapy until the start of the next treatment. The PSAV was calculated using the same PSA values over time. The association with overall survival (OS) from the date of AIPC was analyzed using the Cox proportional hazards regression model.

RESULTS

PSADT and PSAV at the emergence of AIPC were calculated in 91 patients. On univariate analysis, a shorter PSADT and greater PSAV were associated with decreased OS. On multivariate analysis, a PSADT of 12 weeks or less (hazard ratio 3.2), PSAV greater than 10 ng/mL/yr (hazard ratio 2.8), PSA nadir greater than 0.2 with ADT, low hemoglobin, and type of chemotherapy persisted as significant predictors of decreased OS (each P <0.01). A rapid PSADT (12 weeks or less) and high PSAV (greater than 10 ng/mL/yr) predicted for the worst prognosis (25 months median OS, unadjusted). A slow PSADT (greater than 12 weeks), and low PSAV (10 ng/mL/yr or less) predicted for the best prognosis (75 months); other combinations had intermediate prognoses (49 and 50 months).

CONCLUSIONS

The PSAV at the start of AIPC contributes prognostic information independent of the PSADT in patients receiving chemotherapy. Future studies should investigate the relative contribution of each of these factors in predicting survival.

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.

Posttreatment prostatic-specific antigen doubling time as a surrogate endpoint for prostate cancer-specific survival: An analysis of Radiation Therapy Oncology Group Protocol 92–02

PURPOSE

We evaluated whether posttreatment prostatic-specific antigen doubling time (PSADT) was predictive of prostate cancer mortality by testing the Prentice requirements for a surrogate endpoint.

METHODS AND MATERIALS

We analyzed posttreatment PSA measurements in a cohort of 1,514 men with localized prostate cancer (T2c-4 and PSA level <150 ng/mL), treated and monitored prospectively on Radiation Therapy Oncology Group Protocol 92-02. From June 1992 to April 1995, men were randomized to neoadjuvant androgen deprivation and 65-70 Gy of radiation therapy (n = 761), or in combination with 24 months of adjuvant androgen deprivation (n = 753). Using an adjusted Cox proportional hazards model, we tested if PSADT was prognostic and independent of randomized treatment in this cohort. The endpoints were time to PSADT (assuming first-order kinetics for a minimum of 3 rising PSA measurements) and cancer-specific survival (CSS).

RESULTS

After a median follow-up time of 5.9 years, randomized treatment was a significant predictor for CSS (p(Cox) = 0.002), PSADT <6 months (p(Cox) < 0.001), PSADT <9 months (p(Cox) < 0.001), and PSADT <12 months (p(Cox) < 0.001) but not for PSADT <3 (p(Cox) = 0.4). The significant posttreatment PSADTs were also significant predictors of CSS (p(Cox)< 0.001). After adjusting for T stage, Gleason score and PSA, all of Prentice's requirements were not met, indicating that the effect of PSADT on CSS was not independent of the randomized treatment.

CONCLUSIONS

Prostatic specific antigen doubling time is significantly associated with CSS, but did not meet all of Prentice's requirements for a surrogate endpoint of CSS. Thus, the risk of dying of prostate cancer is not fully explained by PSADT.

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.

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.

Conduite à tenir devant une ascension du PSA après rémission complète postprostatectomie ?

Between twenty and to forty percent of patients will develop an isolated PSA failure after a radical prostatectomy. Pelvic irradiation is a therapeutic option with curative intention. It is the best therapeutic option for young people with good prognostic factors. Combined radiation with hormonal or chemotherapy should be evaluated in patients with poor prognostic factors. For patients with a short life expectancy, hormonotherapy or a watch and see policy are acceptable options.

Early initiation of salvage hormone therapy influences survival in patients who failed initial radiation for locally advanced prostate cancer: A secondary analysis of RTOG protocol 86-10

PURPOSE

We examined overall and disease-specific survival outcomes both from the time of initial treatment and from the start of salvage hormone therapy (HT), by the extent of disease progression at the time salvage HT was started in patients treated on RTOG Protocol 86-10.

METHODS

[corrected] With a median follow-up of 9.0 years, 247 patients (54%) had received subsequent salvage HT. The overall survival (OVS) and disease-specific survival (DSS) were compared by the extent of disease progression at the time salvage HT was started.

RESULTS

For those patients with distant metastases (DM) present at the start of salvage HT, the OVS and DSS were significantly reduced when compared to [corrected] those with DM absent at the time salvage HT was started (OVS at 8 years, 31% vs. 58%; DSS at 8 years, 38% vs. 65%). A statistically significant increase in DSS was observed among the 143 patients with DM absent when patients with prostate-specific antigen (PSA) less than 20 were compared with those with PSA greater than 20 at the time salvage HT was started.

CONCLUSION

[corrected] The DSS and the OVS of the relapsed patient are decreased in those with more extensive disease at the time of salvage HT. However, because this protocol could not evaluate the effect of posttreatment PSA velocity on outcomes, which is likely a better predictor of long-term success with salvage HT, these results cannot be taken to demonstrate that early salvage HT in patients with long posttreatment PSA doubling times is necessary for longer survival.

Simple graphic method for estimation of prostate-specific antigen doubling time

The prostate-specific antigen doubling time (PSADT) is of prognostic value in patients with prostate cancer, but computerized algorithms are usually required for PSADT estimation. We present here a simple graphic tool that can be used to estimate the PSADT on the basis of two increasing PSA measurements, separated by 3 to 12 months.

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).

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

OBJECTIVE

To assess the prostate specific antigen (PSA) doubling time of untreated, clinically localized, low-to-intermediate grade prostate carcinoma.

PATIENTS AND METHODS

A prospective single-arm cohort study has been in progress since November 1995 to assess the feasibility of a watchful-observation protocol with selective delayed intervention for clinically localized, low-to-intermediate grade prostate adenocarcinoma. The PSA doubling time was estimated from a linear regression of ln(PSA) against time, assuming a simple exponential growth model.

RESULTS

As of March 2003, 231 patients had at least 6 months of follow-up (median 45) and at least three PSA measurements (median 8, range 3-21). The distribution of the doubling time was: < 2 years, 26 patients; 2-5 years, 65; 5-10 years, 42; 10-20 years, 26; 20-50 years, 16; >50 years, 56. The median doubling time was 7.0 years; 42% of men had a doubling time of >10 years.

CONCLUSIONS

The doubling time of untreated clinically localized, low-to-intermediate grade prostate cancer varies widely.

VALIDATION OF INCREASING PROSTATE SPECIFIC ANTIGEN AS A PREDICTOR OF PROSTATE CANCER DEATH AFTER TREATMENT OF LOCALIZED PROSTATE CANCER WITH SURGERY OR RADIATION

PURPOSE

Many patients who undergo surgery or radiation therapy to treat localized prostate cancer experience an increase in serum prostate specific antigen (PSA) after treatment. This study documents patterns of PSA recurrence after surgery or radiation to treat localized prostate cancer and quantifies the extent to which an increasing PSA predicts death from prostate cancer.

MATERIALS AND METHODS

Posttreatment PSA levels were measured on a population based cohort of 1136 men diagnosed with localized prostate cancer in community practice in Connecticut between 1990 and 1992, and treated within 6 months of diagnosis with surgery or radiation with or without androgen withdrawal therapy. The major outcome measure was death from prostate cancer.

RESULTS

PSA recurrence followed a log-linear pattern over time. Patients who died of prostate cancer had a median PSA doubling time of 0.8 years (25th and 75th percentiles 0.5 to 1.4 years). Patients who did not die of prostate cancer within 10 years of diagnosis had either no posttreatment increase in serum PSA (40%) or had a PSA doubling time longer than 1 year (44%).

CONCLUSIONS

Patients whose posttreatment PSA doubling times before the initiation of androgen withdrawal therapy are less than 1 year are at high risk of dying of prostate cancer within 10 years of diagnosis. Men with PSA recurrences that are doubling at rates greater than 1 year are at low risk of death from prostate cancer within 10 years of diagnosis.

Impact of Volume Weighted Mean Nuclear Volume on Outcomes Following Salvage Radiation Therapy After Radical Prostatectomy

PURPOSE

Although salvage radiation therapy (RT) is a potentially curative treatment option for men with biochemical failure after radical prostatectomy (RP), to our knowledge there are no definitive pretreatment factors predicting patients likely to benefit from this treatment. We examined the impact of volume weighted mean nuclear volume (MNV) of biopsy specimens on disease outcomes and describe its usefulness as a new independent predictor.

MATERIALS AND METHODS

We analyzed 33 patients who received salvage RT for biochemical failure after RP, including 11 who had received neoadjuvant hormone therapy before RP. Salvage RT was delivered to the prostatic bed at a total dose of 60 Gy with a 4-field contoured technique. Unbiased estimates of MNV were calculated from more than 100 cancer nuclei per patient captured from biopsy specimens based on a stereological method and compared with other clinical and pathological findings, including patient age, pretreatment prostate specific antigen (PSA), PSA density, biopsy Gleason score, neoadjuvant therapy, surgical Gleason score, pathological stage, tumor volume, surgical margin status, biochemical disease-free duration before RT, nadir PSA and PSA doubling time before RT, and pre-RT PSA with regard to predicting the disease outcome after salvage RT.

RESULTS

The median followup after salvage RT was 43.4 months. A total of 17 patients (52%) experienced biochemical failure a median of 6.7 months (range 0 to 48.1) after RT. On univariate analysis MNV and log(pre-RT PSA) were significant predictors of disease outcome in all patients and in the 22 nonneoadjuvant patient subset (p = 0.0124 and 0.0159, respectively). Log(nadir PSA) and PSA doubling time were also significant in the latter subset (p = 0.0287 and 0.0475, respectively). However, dual multivariate analysis revealed that MNV was the only independent predictor in the 2 groups (logistic regression analysis p = 0.00931 and 0.03511, and Cox proportional hazards analysis p = 0.00483 and 0.02277, respectively). There was a statistically significant biochemical disease-free survival advantage for small vs large MNV in each data set (p = 0.0072 and 0.0036, respectively).

CONCLUSIONS

Our results suggest that an estimate of MNV contributes significantly to the prediction of biochemical control after salvage RT. However, further investigation in a larger nonneoadjuvant population is needed to confirm its significance in combination with other clinical and pathological findings.

Short-term androgen deprivation and PSA doubling time: their association and relationship to disease progression after radiation therapy for prostate cancer

PURPOSE

The goal of this study was to investigate the relationship between PSA doubling time (PSADT) and initial management of prostate cancer with short-term androgen deprivation (STAD) and the impact of these factors on disease progression after radiation therapy.

METHODS AND MATERIALS

Between May 1989 and October 1998, 284 patients treated with 3D-CRT experienced biochemical failure (BF) as defined under the ASTRO consensus statement. All patients had sufficient follow-up data for PSADT calculations. Linear regression was used to assess predictors of PSADT among STAD, time to biochemical failure (TTBF), Gleason Score, tumor stage, dose, posttreatment PSA nadir, pretreatment PSA, and age. A composite covariate was created from the various combinations of factors found to be predictive of PSADT. The composite covariate was then included, along with PSADT and the factors previously mentioned, in proportional hazards modeling of freedom from distant metastasis (FDM), cause-specific survival (CSS), and overall survival (OS).

RESULTS

Fifty-four (19%) patients developed distant metastasis, 20 (7%) died of prostate cancer, and 53 (19%) died of any cause. The median PSADT was 12 months. Predictors of a longer PSADT were TTBF >12 months, Gleason Score 2-6, and STAD. An ordinal composite covariate was created with eight levels on the basis of the magnitude of observed mean PSADT within the eight possible combinations of the three dichotomized predictors. The most significant predictor of higher FDM rates in Cox modeling was the composite covariate, followed by longer PSADT, STAD, lower PSA nadir, higher RT dose, and Gleason Score 2-6. Predictors of higher CSS rates were lower nadir, longer PSADT, T1/T2ab tumors, the composite covariate, and STAD. The most significant predictor of a higher OS rate was STAD, followed by longer PSADT, younger age at diagnosis, the composite covariate, lower nadir, and T1/T2ab tumors.

CONCLUSIONS

Longer TTBF, Gleason Score 2-6 tumors, and STAD were predictive of longer PSADT. Even after adjusting for these factors in the capacity of their predictive properties for PSADT, STAD and observed PSADT continued to be significant independent predictors of FDM, CSS, and OS. STAD appears to have a pronounced impact on disease progression, probably the result partly of the prolongation of PSADT.

Prostate-specific antigen doubling time and survival in patients with advanced metastatic prostate cancer

The relation between tumor kinetics and disease progression in patients with hormone-refractory prostate cancer (HRPC) has not been well described. Biochemical recurrence of prostate cancer is characterized by detectable prostate-specific antigen (PSA) levels after treatment and occurs in approximately 30% of patients after therapy for apparent localized disease. An increase in PSA almost always occurs before clinical evidence of disease. The ability to identify early biochemical failure in patients to assess disease aggressiveness and guide changes in treatment needs to be examined. We examined serial PSA data from 249 patients with metastatic disease to assess PSA doubling time (PSADT) in hormone-naive prostate cancer (HNPC) and HRPC states. In a subset of patients, the relation of PSADT to Gleason score and survival was studied. PSADT decreased from 37.5 +/- 4.5 weeks to 15.6 +/- 1.6 weeks (mean +/- SEM) in patients with HNPC versus HRPC. In this small study, PSADT did not correlate with Gleason score, survival from start of hormonal treatment, length of time receiving hormone therapy, or survival in the HRPC state. The decrease in PSADT with disease state may help provide insight into understanding the biology of late-stage disease.

Markers and meaning of primary treatment failure

BCR is the most clinically used endpoint for identification of treatment failure. Approximately 15% to 53% of patients undergoing primary curative therapy will develop BCR. BCR often precedes clinically detectable recurrence by years. It does not necessarily translate directly into PCa morbidity and mortality, nor does it always reflect the desired endpoint. Furthermore, it has not been validated as a surrogate endpoint, in that interventions that have been shown to alter the PSA level have not been shown to also alter survival. The utility of PSA level as a surrogate endpoint is brought into question by the knowledge that the overall survival rate of patients at 10 years is similar in patients with and without BCR, and that in a significant proportion of men, the only evidence of disease during their lifetime will be a detectable PSA level. The likelihood of developing BCR post-therapy can be predicted by using multiple clinical and pathologic variables. With the development of nomograms that incorporate several markers, the accuracy of prediction has improved. Until recently, the natural history of BCR post-RRP has not been well understood. Pound et al showed the heterogenous and prolonged natural history of BCR. In this large series of men with BCR following RRP, only 34% of men developed metastatic disease. The median time from development of BCR to identification of metastases was 8 years, and the median time from the development of metastatic disease to death was just under 5 years. These data highlight the extremely variable and potentially indolent nature of BCR. The risk of metastatic disease following BCR has been relatively well defined and relates to PSADT and time to PSA recurrence. It generally is accepted that a PSADT of less than 6 to 10 months and a time to PSA recurrence of less than 1 to 2 years relates to a higher risk of developing metastatic disease. Local recurrence, however, remains poorly understood with respect to its true incidence, clinical significance, and natural history. The significance of BCR post-RT remains unclear due to the lack of data on its natural history. Attempts have been made to identify patients at high risk for metastatic progression by looking at time to PSA recurrence and PSADT. A PSADT of less than 6 to 12 months and a time to PSA recurrence of less than 12 months reflects a higher risk of developing metastatic disease. Accurate risk stratification by means of an algorithm similar to that produced by Pound et al has not been performed on a large cohort, thus making risk assessment for an individual patient difficult. The major dilemma for clinicians in the management of BCR is the identification of the site of disease recurrence, which ultimately guides therapy decisions. Clinicopathologic features allow for risk stratification for recurrence, and multiple investigations have attempted to localize the site of recurrence. Time to biochemical progression, Gleason score, and PSADT are predictive of the probability and time to development of metastatic disease, and allow for stratification of patients into different risk groups (see Table 2). TRUS, CT, PET, and DRE all have limited utility in the identification of local recurrence. ProstaScint and MRI have demonstrated encouraging initial results: however, they require further investigation. Bone scintigraphy is of little value for the initial investigation of BCR. In patients with a PSA level of less than 10 ng/mL, the risk of having a positive bone scan is less than 1% and, until the PSA level rises above 40 ng/mL, the risk of having a positive bone scan is less than 5%. Therefore, bone scintigraphy should be reserved for patients with a PSA level greater than 10 to 20 ng/mL or patients with a rapidly rising PSA level. Using new MRI sequences, there is some evidence that MRI is better for the detection of bony metastatic disease; however, this technique requires further investigation. BCR causes anxiety for the patient and the treating doctor, because the best way to manage patients with PSA-only progression is unknown. Currently, there are no validated treatment recommendations for the management of BCR. The information in this review provides the framework for assignment of patients into clinical trials based on different risk categories. Patients at high risk for metastatic progression could be identified early and thus entered into appropriate clinical trials for systemic therapies. Similarly, patients with a low risk of progression could be placed into observation protocols, potentially sparing them from exhaustive and inappropriate investigations.

Posttreatment prostate-specific antigen nadir highly predictive of distant failure and death from prostate cancer

PURPOSE

To link posttreatment biochemical profiles to distant failure and cause-specific survival by assessing the relationship between posttreatment prostate-specific antigen (PSA) nadir and PSA doubling time (PSADT) with these outcome measures.

METHODS AND MATERIALS

A total of 615 men were treated at the Fox Chase Cancer Center between April 1989 and December 1995 with three-dimensional conformal radiotherapy alone (median dose 73 Gy). The median follow-up was 64 months (range 2-135). Kaplan-Meier methods were used to estimate the rates of biochemical control, freedom from distant metastasis (FDM), and cause-specific survival. Multivariate predictors of outcome were assessed using stepwise Cox regression analysis.

RESULTS

Multivariate analyses demonstrated that the predictors of improved biochemical control were a lower PSA nadir (p <0.0001), lower pretreatment PSA level (p <0.0001), Gleason score of 2-6 (p = 0.001), Stage T1-T2a tumors (p = 0.03), and higher RT dose (p = 0.02). The predictors of improved FDM were a lower PSA nadir (p <0.0001), longer interval to nadir from start of treatment (p = 0.0002), Gleason score of 2-6 (p = 0.005), androgen deprivation for biochemical failure (p = 0.001), and Stage T1-T2a tumors (p = 0.01). The predictors of improved cause-specific survival were a lower PSA nadir (p = 0.006) and longer interval to nadir from the start of treatment (p = 0.03). The 8-year FDM rate was 96%, 89%, and 61% for PSA nadir values of <or=1.0, 1.1-2.0, and >2.0 ng/mL (p <0.0001), respectively. The 8-year cause-specific survival rate was 97%, 96%, and 78% for posttreatment PSA nadir values of <or=1.0, 1.1-2.0, and >2.0 ng/mL (p <0.0001), respectively. For patients with sufficient PSA follow-up for PSADT calculations (n = 136), multivariate analysis of FDM from the time of biochemical failure demonstrated that androgen deprivation (p = 0.001), longer PSADT (p = 0.003), lower PSA nadir (p = 0.02), and longer interval to nadir from start of treatment (p = 0.04) were independent predictors of improved FDM.

CONCLUSION

This is the first study, to our knowledge, to demonstrate the overwhelming predictive power of posttreatment PSA nadir for distant failure and death from prostate cancer. It is also the first study, to our knowledge, to demonstrate a strong association between posttreatment PSADT and distant failure. The results provide new information regarding disease progression as a function of posttreatment PSA profiles (time to achieve nadir from start of treatment, nadir, and PSADT) and the timing of androgen deprivation for biochemical relapse. This study may be used for the early identification of patients at high risk of distant metastasis and who may be directed to applicable systemic treatment clinical trials.

Utility of PSA doubling time in follow-up of untreated patients with localized prostate cancer

OBJECTIVES

To evaluate the prostate-specific antigen (PSA) changes and the ability of PSA doubling time (PSADT) to predict disease progression in untreated patients with clinically localized prostate cancer.

METHODS

A total of 104 patients with localized prostate cancer were followed up expectantly with serial PSA measurements and digital rectal examination (DRE). PSADT was calculated by linear regression analysis for the 94 patients who had a minimum of three PSA measurements and 12 months of follow-up. The median follow-up was 33 months. Of the 94 patients, 45 underwent repeat prostate biopsy to evaluate whether tumor progression occurred during the observation period.

RESULTS

Twenty-seven percent of patients had rapid PSADTs (less than 48 months). Only the presence of palpable disease on DRE correlated with a PSADT of less than 48 months (P <0.05). However, a PSADT of less than 120 months consistently correlated with disease progression on DRE and on repeat biopsy, as well as with the presence of clinically significant cancer. PSADT did not correlate with the Gleason score. Furthermore, patients with a PSADT of less than 48 months did not differ significantly from those with a PSADT of 48 to 120 months with regard to Gleason score, disease progression on DRE or on repeat biopsy, and the presence of significant cancer.

CONCLUSIONS

A PSADT of less than 120 months correlates with disease progression. However, its clinical utility remains limited to identify patients at risk of disease progression reliably.

The role of androgen ablation in patients with biochemical or local failure after definitive radiation therapy: a survey of practice patterns of urologists and radiation oncologists in the United States

To identify therapeutic patterns for putative prostate cancer treatment failures and the role played by androgen ablation therapy in these patients, a questionnaire study was undertaken with urologists and radiation oncologists who had attended a brachytherapy forum at the Seattle Prostate Institute (SPI). Hypothetical questions were asked about recommendations the physicians would give to a patient demonstrating biochemical or local failure after external-beam radiation therapy. Most of the physicians queried were in private practice; 53% were radiation oncologists and 47% were urologists. The respondents' recommendations for a hypothetical patient, who was 45 to 65 years of age, with a biopsy-proven local recurrence was treatment with androgen ablation (35% of respondents), radical prostatectomy (25%), interstitial brachytherapy (20%), and observation (19%). In the 65- to 75-year-old patient with a local recurrence, the respondents recommended observation (43%), androgen ablation (35%), interstitial brachytherapy (17%), and radical prostatectomy (4%). In patients receiving androgen ablation for a biochemical failure alone, there was no consensus on whether to use luteinizing hormone-releasing hormone agonist alone, total androgen ablation, orchiectomy, or intermittent androgen ablation. Criteria that prompted physicians to initiate androgen ablation were based on the rate of prostate-specific antigen (PSA) increase (67%), an absolute PSA number (24%), or clinical failure (9%). In the younger patient with a local recurrence, local intervention with radical prostatectomy or interstitial brachytherapy was recommended most often, followed by androgen ablation, then by observation. In the older patient, observation was recommended most often, followed closely by androgen ablation. Overall, there was a lack of consensus on how to deliver androgen ablation. However, there was remarkable agreement between urologists and radiation oncologists on virtually all issues queried.

PSA doubling time of prostate carcinoma managed with watchful observation alone

PURPOSE

To study prostate-specific antigen (PSA) doubling time of untreated, favorable grade, prostate carcinoma.

METHODS AND MATERIALS

A prospective single-arm cohort study has been in progress to assess the feasibility of a watchful observation protocol with selective delayed intervention using clinical, histologic, or PSA progression as treatment indication in untreated, localized, favorable grade prostate adenocarcinoma (T1b-T2bN0 M0, Gleason Score < or = 7, and PSA < or = 15 ng/mL). Patients are conservatively managed with watchful observation alone, as long as they do not meet the arbitrarily defined disease progression criteria. Patients are followed regularly and undergo blood tests including PSA at each visit. PSA doubling time (Td) is estimated from a linear regression of ln(PSA) on time, assuming a simple exponential growth model.

RESULTS

As of March 2000, 134 patients have been on the study for a minimum of 12 months (median, 24; range, 12-52) and have a median frequency of PSA measurement of 7 times (range, 3-15). Median age is 70 years. Median PSA at enrollment is 6.3 (range, 0.5-14.6). The distribution of Td is as follows: <2 years, 19 patients; 2-5 years, 46; 5-10 years, 25; 10-20 years, 11; 20-50 years, 6; > 50 years, 27. The median Td is 5.1 years. In 44 patients (33%), Td is greater than 10 years. There was no correlation between Td and patient age, clinical T stage, Gleason score, or initial PSA level.

CONCLUSION

Td of untreated prostate cancer varies widely. In our cohort, 33% have Td > 10 years. Td may be a useful tool to guide treatment intervention for patients managed conservatively with watchful observation alone.

Chemical disease-free survival in localized carcinoma of prostate treated with external beam irradiation: comparison of American Society of Therapeutic Radiology and Oncology Consensus or 1 ng/mL as endpoint

PURPOSE

To compare postirradiation biochemical disease-free survival using the American Society of Therapeutic Radiology and Oncology (ASTRO) Consensus or elevation of postirradiation prostate-specific antigen (PSA) level beyond 1 ng/mL as an endpoint and correlate chemical failure with subsequent appearance of clinically detected local recurrence or distant metastasis.

METHODS AND MATERIALS

Records of 466 patients with histologically confirmed adenocarcinoma of the prostate treated with irradiation alone between January 1987 and December 1995 were analyzed; 339 patients were treated with bilateral 120 degrees arc rotation and, starting in 1992, 117 with three-dimensional conformal irradiation. Doses were 68--77 Gy in 1.8 to 2 Gy daily fractions. Minimum follow-up is 4 years (mean, 5.5 years; maximum, 9.6 years). A chemical failure was recorded using the ASTRO Consensus or when postirradiation PSA level exceeded 1 ng/mL at any time. Clinical failures were determined by rectal examination, radiographic studies, and, when clinically indicated, biopsy.

RESULTS

Six-year chemical disease-free survival rates using the ASTRO Consensus according to pretreatment PSA level for T1 tumors were: < or = 4 ng/mL, 100%; 4.1--20 ng/mL, 80%; and > 20 ng/mL, 50%. For T2 tumors the rates were: < or = 4 ng/mL, 91%; 4.1--10 ng/mL, 81%; 10.1--20 ng/mL, 55%; 20.1--40 ng/mL, 63%; and > 40 ng/mL, 46%. When postirradiation PSA levels higher than 1 ng/mL were used, the corresponding 6-year chemical disease-free survival rates for T1 tumors were 92% for pretreatment PSA levels of < or = 4 ng/mL, 58--60% for levels of 4.1--20 ng/mL, and 30% for levels > 20 ng/mL. For T2 tumors, the 6-year chemical disease-free survival rates were 78% in patients with pretreatment PSA levels of 4--10 ng/mL, 45% for 10.1--40 ng/mL, and 25% for > 40 ng/mL. Of 167 patients with T1 tumors, 30 (18%) developed a chemical failure, 97% within 5 years from completion of radiation therapy; no patient has developed a local recurrence or distant metastasis. In patients with T2 tumors, overall 45 of 236 (19%) had chemical failure, 94% within 5 years of completion of radiation therapy; 4% have developed a local recurrence, and 10%, distant metastasis. In patients with T3 tumors, overall, 24 of 65 (37%) developed a chemical failure, 100% within 3.5 years from completion of radiation therapy; 4% of these patients developed a local recurrence within 2 years, and 12% developed distant metastasis within 4 years of completion of irradiation. The average time to clinical appearance of local recurrence or distant metastasis after a chemical failure was detected was 5 years and 3 years, respectively.

CONCLUSION

There was a close correlation between the postirradiation nadir PSA and subsequent development of a chemical failure. Except for patients with T1 tumors and pretreatment PSA of 4.1--20 ng/mL, there is good agreement in 6-year chemical disease-free survival using the ASTRO Consensus or PSA elevations above 1 ng/mL as an endpoint. Although the ASTRO Consensus tends to give a higher percentage of chemical disease-free survival in most groups, the differences with longer follow-up are not statistically significant (p > 0.05). It is important to follow these patients for at least 10 years to better assess the significance of and the relationship between chemical and clinical failures.

Preoperative PSA velocity and doubling time do not predict adverse pathologic features or biochemical recurrence after radical prostatectomy

OBJECTIVES

To improve the accuracy of predicting pathologic stage and biochemical recurrence after radical prostatectomy (RP), we sought to determine whether preoperative prostate-specific antigen (PSA) velocity and doubling time predict adverse pathologic features or biochemical recurrence following RP. We also sought to determine if there were racial differences in preoperative PSA velocity and doubling time.

METHODS

A total of 331 patients underwent RP at the West Los Angeles VA Medical Center between November 1991 and March 2000. Of these patients, 86 had two or more preoperative PSA values that were at least 12 months apart. Patients were analyzed to determine whether preoperative PSA velocity or doubling time was predictive of adverse pathologic features, including positive surgical margins, capsular penetration, seminal vesicle invasion, or biochemical recurrence. Additionally, PSA velocity and doubling time were compared among white, black, Hispanic, and Asian men.

RESULTS

Preoperative PSA velocity and doubling time were not predictive of positive surgical margins, capsular penetration, or seminal vesicle invasion (P >0.30). In addition, there was no association between PSA velocity or doubling time and pathologic stage or surgical Gleason score (P >0.36). Preoperative PSA velocity (P = 0.581) and doubling time (P = 0.528) were not predictors of biochemical recurrence following RP. There were no racial differences in preoperative PSA velocity (P = 0.715) or doubling time (P = 0.662).

CONCLUSIONS

Neither preoperative PSA velocity nor doubling time was a predictor of adverse pathologic findings or biochemical recurrence after RP. In addition, there was no difference in PSA velocity or doubling time between the races studied.