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

Tumour growth rates of prostate cancer during active surveillance: is there a difference between MRI-visible low and intermediate-risk disease?

OBJECTIVES

The aim of this study was to evaluate the changes in lesion volume on serial multiparametric magnetic resonance (mpMRI) during active surveillance for prostate cancer.

METHODS

A total of 160 patients with a targeted biopsy-confirmed visible lesion on mpMRI, stratified by low- and intermediate-risk disease (Gleason Grade Group 1 vs Gleason Grade Group 2), were analysed. The % change per year was calculated using the formula: [(final volume/initial volume) exp (1/interval between scans in years)]-1.

RESULTS

There was no significant difference in the annual median percentage change between Gleason Grade Group 1 (18%) and Gleason Grade Group 2 (23%) disease (p = 0.16), and between ≤ 10% (23%) and > 10% (22%) of Gleason pattern 4 (p = 0.78).Assuming a spherical lesion, these changes corresponded to annual increases in mean tumour diameter of 6% and 7% for Gleason Grade Group 1 and Gleason Grade Group 2 respectively, which may be less than the interscan variability of serial mpMRI.

CONCLUSION

In an active surveillance cohort, we did not see a significant difference in the annual growth rate of Gleason Grade Group 1 and 2 tumours.

ADVANCES IN KNOWLEDGE

In patients on active surveillance, the measured growth rates for visible tumours in Gleason Grade Groups 1 and 2 were similar. The annual growth rate was small in most cases and this may have implications for the MRI follow-up interval in active surveillance.

The Predictive Role of Prostate-Specific Antigen Changes Following Transurethral Resection of the Prostate for Patients with Localized Prostate Cancer

Simple Summary

A part of localized prostate cancer (PC) was an incidental finding in patients who received transurethral resection of the prostate (TURP) for urinary symptoms. The present study examined whether changes in prostate-specific antigen (PSA) levels after TURP possess a predictive value for localized PC. Our data revealed that patients at intermediate risk who are associated with tumor involvement ≤5% in TURP specimens, PSA_TURP ≤ 4 ng/mL, and ≥68% PSA reduction following TURP might be suitable for conservation management instead of immediate local therapy. Moreover, for patients with no pre-TURP PSA, Gleason score (GS) < 7, and low PSA_TURP could potentially be utilized to select which patients could be considered for conservative management after TURP. The findings suggest the pathologic finding of TURP and changes in PSA could be used as adjuvant markers to guide a risk-adaptive strategy for patients with localized PC.

Abstract

Regarding localized prostate cancer (PC), questions remain regarding which patients are appropriate candidates for conservative management. Some localized PC was an incidental finding in patients who received transurethral resection of the prostate (TURP) for urinary symptoms. It is known that TURP usually affects the level of prostate-specific antigen (PSA). In the present study, we examined whether changes in PSA levels after TURP possess a predictive value for localized PC. We retrospectively reviewed the clinical data of 846 early-stage PC patients who underwent TURP for urinary symptoms upon diagnosis at our hospital. Of 846 patients, 687 had tumor involvement in TURP specimens, and 362 had post-TURP PSA assessment. Our data revealed that, in addition to low GS and PSA levels at diagnosis, ≤5% tumor involvement in TURP specimens, greater PSA reduction (≥68%) following TURP, and post-TURP PSA ≤ 4 were significantly associated with better progression-free survival (PFS). Survival analysis revealed that the addition of prostate-directed local therapy significantly improved PFS in intermediate- and high-risk groups, but not in the low-risk group. Moreover, in the intermediate-risk group, local therapy improved PFS only for patients who were associated with post-TURP PSA > 4 ng/mL or <68% PSA reduction following TURP. We also found that local therapy had no obvious improvement in PFS for those with post-TURP ≤ 4 ng/mL regardless of pre-TURP PSA. In conclusion, conservative management is considered for patients at low or intermediate risk who have greater PSA reduction following TURP and low post-TURP PSA. Therefore, the levels of PSA following TURP might be helpful for risk stratification and the selection of patients for conservative management.

Evaluation of serum fatty acid binding protein-4 (FABP-4) as a novel biomarker to predict biopsy outcomes in prostate biopsy naïve patients

OBJECTIVES

To investigate the role of serum fatty acid-binding protein-4 (FABP-4) as a surrogate of obesity and metabolic syndrome in the prediction of the outcome of prostate biopsy.

METHODS

A prospective pilot study was conducted for patients undergoing prostate needle biopsy (PNB) for clinically suspected prostate cancer (PCa) between June 2016 and August 2017. Fifty consecutive patients with biopsy-proven PCa were included as study group and 50 consecutive patients with negative biopsy were included as a control group. Receiver Operating Characteristic (ROC) curve was used to calculate the area under the curve (AUC) to compare the accuracy of the different parameters in the diagnosis as well as the presence of high-grade PCa (Gleason score 8-9) at PNB. Predictors of the outcome were analyzed using univariate and multivariate logistic regression analysis.

RESULTS

FABP-4 (AUC: 0.75; P < 0.001) and PSA-density (AUC: 0.84; P < 0.001) were the most accurate to detect PCa at PNB. On multivariate analysis, FABP-4 > 22.5 ng/ml (OR: 16.6; 95% CI 2.8-98; P = 0.002) and PSA-density > 0.38 ng/ml/ml OR: 17.7; 95% CI 5.3-59; P < 0.001) were independent predictors of PCa detection. Regarding high-grade PCa at PNB, FABP-4 (AUC: 0.79; P < 0.001) and %Free-PSA (AUC: 0.75; P < 0.001) were the most accurate. Independent predictors of high-grade PCa were FABP-4 > 32.3 ng/ml OR: 9.2; 95% CI 1.8-45; P = 0.006) and %Free-PSA ≤ 21.9 (OR: 5.5; 95% CI 1.1-27; P = 0.03).

CONCLUSIONS

FABP-4 is an independent predictor for both the diagnosis and high-grade Gleason score at PNB. This novel biomarker might have a promising role in optimizing PNB outcomes.

Refined Analysis of Prostate-specific Antigen Kinetics to Predict Prostate Cancer Active Surveillance Outcomes

BACKGROUND

For men on active surveillance for prostate cancer, utility of prostate-specific antigen (PSA) kinetics (PSAk) in predicting pathologic reclassification remains controversial.

OBJECTIVE

To develop prediction methods for utilizing serial PSA and evaluate frequency of collection.

DESIGN, SETTING, AND PARTICIPANTS

Data were collected from men enrolled in the multicenter Canary Prostate Active Surveillance Study, for whom PSA data were measured and biopsies performed on prespecified schedules. We developed a PSAk parameter based on a linear mixed-effect model (LMEM) that accounted for serial PSA levels.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The association of diagnostic PSA and/or PSAk with time to reclassification (increase in cancer grade and/or volume) was evaluated using multivariable Cox proportional hazards models.

RESULTS AND LIMITATIONS

A total of 851 men met the study criteria; 255 (30%) had a reclassification event within 5 yr. Median follow-up was 3.7 yr. After adjusting for prostate size, time since diagnosis, biopsy parameters, and diagnostic PSA, PSAk was a significant predictor of reclassification (hazard ratio for each 0.10 increase in PSAk=1.6 [95% confidence interval 1.2-2.1, p<0.001]). The PSAk model improved stratification of risk prediction for the top and bottom deciles of risk over a model without PSAk. Model performance was essentially identical using PSA data measured every 6 mo to those measured every 3 mo. The major limitation is the reliability of reclassification as an end point, although it drives most treatment decisions.

CONCLUSIONS

PSAk calculated using an LMEM statistically significantly predicts biopsy reclassification. Models that use repeat PSA measurements outperform a model incorporating only diagnostic PSA. Model performance is similar using PSA assessed every 3 or 6 mo. If validated, these results should inform optimal incorporation of PSA trends into active surveillance protocols and risk calculators.

PATIENT SUMMARY

In this report, we looked at whether repeat prostate-specific antigen (PSA) measurements, or PSA kinetics, improve prediction of biopsy outcomes in men using active surveillance to manage localized prostate cancer. We found that in a large multicenter active surveillance cohort, PSA kinetics improves the prediction of surveillance biopsy outcome.

Utility of early transperineal template-guided prostate biopsy for risk stratification in men undergoing active surveillance for prostate cancer

OBJECTIVE

To assess the accuracy and utility of routine multiparametric magnetic resonance imaging (mpMRI) and transperineal template-guided prostate biopsy (TPB) after enrolment in active surveillance (AS).

PATIENTS AND METHODS

From April 2012 to December 2016 consecutive men from our single institution, diagnosed with low- or intermediate-risk prostate cancer on transrectal ultrasonography-guided biopsy, were offered further staging with early mpMRI and TPB within 12 months of diagnosis. Data were collected prospectively. Eligibility criteria comprised: age ≤77 years; Gleason score ≤3 + 4; clinical stage T1-T2; PSA ≤15 ng/mL; and <50% positive biopsy cores.

RESULTS

A total of 208 men were enrolled, including 196 with Gleason score 3 + 3 and 12 with Gleason score 3 + 4 disease. The median (range) number of TPB cores was 50 (17-161), with a mean TPB core density of 1.2 cores/cm³ prostate volume. A total of 83 men (39.9%) underwent histopathological upgrading after TPB, including 76 men (38.8%) with Gleason score 3 + 3 disease and seven men (58.3%) with Gleason score 3 + 4 disease. Of these, 26 (31.3%) were found to harbour primary pattern Gleason grade ≥4 disease. In all, 24 (28.9%) upgraded cases had Prostate Imaging Reporting and Data System (PI-RADS) score 1 or 2 lesions on mpMRI, including five men with Gleason score ≥4 + 3 disease. Of these, 14 (58.3%) had a prostate-specific antigen (PSA) density of ≥0.15, including four out of the five men with Gleason ≥4 + 3 disease. Overall there was a change in prostate cancer management in 77 men (37.0%) after TPB.

CONCLUSIONS

Early TPB during AS is associated with significant upgrading and a change in treatment plan in over a third of men. If TPB was omitted in men with a PI-RADS score <3 and a PSA density <0.15, 12% of those harbouring more significant disease would have been misclassified.

Prostate-specific antigen patterns in US and European populations: comparison of six diverse cohorts

OBJECTIVE

To determine whether there are differences in prostate-specific antigen (PSA) levels at diagnosis or changes in PSA levels between US and European populations of men with and without prostate cancer (PCa).

SUBJECTS AND METHODS

We analysed repeated measures of PSA from six clinically and geographically diverse cohorts of men: two cohorts with PSA-detected PCa, two cohorts with clinically detected PCa and two cohorts without PCa. Using multilevel models, average PSA at diagnosis and PSA change over time were compared among study populations.

RESULTS

The annual percentage PSA change of 4-5% was similar between men without cancer and men with PSA-detected cancer. PSA at diagnosis was 1.7 ng/mL lower in a US cohort of men with PSA-detected PCa (95% confidence interval 1.3-2.0 ng/mL), compared with a UK cohort of men with PSA-detected PCa, but there was no evidence of a different rate of PSA change between these populations.

CONCLUSION

We found that PSA changes over time are similar in UK and US men diagnosed through PSA testing and even in men without PCa. Further development of PSA models to monitor men on active surveillance should be undertaken in order to take advantage of these similarities. We found no evidence that guidelines for using PSA to monitor men cannot be passed between US and European studies.

PET/CT with (18)F-choline after radical prostatectomy in patients with PSA ≤2 ng/ml. Can PSA velocity and PSA doubling time help in patient selection?

PURPOSE

To investigate the performance of (18)F-fluorocholine ((18)F-FCH) PET/CT in relation to the prostate-specific antigen (PSA) kinetic indexes, PSA doubling time (PSAdt) and PSA velocity (PSAve), in detecting recurrent prostate cancer (PC) in a selected population of patients treated with radical prostatectomy and with PSA ≤2 ng/ml.

METHODS

The study group comprised 79 patients (mean age 70 ± 7 years, range 58 - 77 years) who had been treated with radical surgery 30 to 90 months previously and with biochemical failure (defined as a measurable serum PSA level) who were evaluated with (18)F-FCH PET/CT. In order to establish the optimal threshold for PSAdt and PSAve, the diagnostic performance of PSA, PSAdt and PSAve were compared by receiver operating characteristic analysis.

RESULTS

In the population examined, PSA (mean ± SD) was 1.37 ± 0.44 ng/ml (range 0.21 - 2 ng/ml) before PET/CT examination, PSAdt was 10.04 ± 16.67 months and PSAve was 2.75 ± 3.11 ng/ml per year. (18)F-FCH PET/CT was positive in 44 patients (55 %). PSAve and PSAdt were significantly different between patients with a positive and a negative (18)F-FCH PET/CT scan. Thresholds of 6 months for PSAdt and 1 ng/ml per year for PSAve were selected. For PSAdt ≤6 months the detection rate (DR) was 65 %, and for PSAve >1 ng/ml per year the DR was 67 %. PSA values were not significantly different between patients with a positive and a negative PET/CT scan.

CONCLUSION

The results of our study suggest that (18)F-FCH PET/CT could be considered for the evaluation of patients with biochemical recurrence of PC and with low PSA levels. Fast PSA kinetics could be useful in the selection of these patients.

Biomarkers for prostate cancer: present challenges and future opportunities

Prostate cancer (PCa) has variable biological potential with multiple treatment options. A more personalized approach, therefore, is needed to better define men at higher risk of developing PCa, discriminate indolent from aggressive disease and improve risk stratification after treatment by predicting the likelihood of progression. This may improve clinical decision-making regarding management, improve selection for active surveillance protocols and minimize morbidity from treatment. Discovery of new biomarkers associated with prostate carcinogenesis present an opportunity to provide patients with novel genetic signatures to better understand their risk of developing PCa and help forecast their clinical course. In this review, we examine the current literature evaluating biomarkers in PCa. We also address current limitations and present several ideas for future studies.

Active surveillance for low-risk prostate cancer

Overtreatment of prostate cancer has become evident as studies comparing radical prostatectomy vs watchful waiting have shown that radical treatment benefits only a proportion of patients. Active surveillance was introduced as a management option for prostate cancer at low-risk of progression with the aim to closely observe for disease progression or change of tumour characteristics and offer active treatment if and when necessary. Active surveillance has been reserved for patients with Gleason 6 localised disease and low PSA; however, selection criteria may be widened as intermediate-term outcomes demonstrate excellent safety, efficacy and patient acceptance.

Development, validation and evaluation of an instrument for active monitoring of men with clinically localised prostate cancer: systematic review, cohort studies and qualitative study

Background

Active surveillance [(AS), sometimes called active monitoring (AM)],is a National Institute for Health and Care Excellence-recommended management option for men with clinically localised prostate cancer (PCa). It aims to target radical treatment only to those who would benefit most. Little consensus exists nationally or internationally about safe and effective protocols for AM/AS or triggers that indicate if or when men should move to radical treatment.

Objective

The aims of this project were to review how prostate-specific antigen (PSA) has been used in AM/AS programmes; to develop and test the validity of a new model for predicting future PSA levels; to develop an instrument, based on PSA, that would be acceptable and effective for men and clinicians to use in clinical practice; and to design a robust study to evaluate the cost-effectiveness of the instrument.

Methods

A systematic review was conducted to investigate how PSA is currently used to monitor men in worldwide AM/AS studies. A model for PSA change with age was developed using Prostate testing for cancer and Treatment (ProtecT) data and validated using data from two PSA-era cohorts and two pre-PSA-era cohorts. The model was used to derive 95% PSA reference ranges (PSARRs) across ages. These reference ranges were used to predict the onset of metastases or death from PCa in one of the pre-PSA-era cohorts. PSARRs were incorporated into an active monitoring system (AMS) and demonstrated to 18 clinicians and 20 men with PCa from four NHS trusts. Qualitative interviews investigated patients’ and clinicians’ views about current AM/AS protocols and the acceptability of the AMS within current practice.

Results

The systematic review found that the most commonly used triggers for clinical review of PCa were PSA doubling time (PSADT) < 3 years or PSA velocity (PSAv) > 1 ng/ml/year. The model for PSA change (developed using ProtecT study data) predicted PSA values in AM/AS cohorts within 2 ng/ml of observed PSA in up to 79% of men. Comparing the three PSA markers, there was no clear optimal approach to alerting men to worsening cancer. The PSARR and PSADT markers improved the modelc-statistic for predicting death from PCa by 0.11 (21%) and 0.13 (25%), respectively, compared with using diagnostic information alone [PSA, age, tumour stage (T-stage)]. Interviews revealed variation in clinical practice regarding eligibility and follow-up protocols. Patients and clinicians perceive current AM/AS practice to be framed by uncertainty, ranging from uncertainty about selection of eligible AM/AS candidates to uncertainty about optimum follow-up protocols and thresholds for clinical review/radical treatment. Patients and clinicians generally responded positively to the AMS. The impact of the AMS on clinicians’ decision-making was limited by a lack of data linking AMS values to long-term outcomes and by current clinical practice, which viewed PSA measures as one of several tools guiding clinical decisions in AM/AS. Patients reported that they would look to clinicians, rather than to a tool, to direct decision-making.

Limitations

The quantitative findings were severely hampered by a lack of clinical outcomes or events (such as metastases). The qualitative findings were limited through reliance on participants’ reports of practices and recollections of events rather than observations of actual interactions.

Conclusions

Patients and clinicians found that the instrument provided additional, potentially helpful, information but were uncertain about the current usefulness of the risk model we developed for routine management. Comparison of the model with other monitoring strategies will require clinical outcomes from ongoing AM/AS studies.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Transurethral resection of the prostate for patients with Gleason score 6 prostate cancer and symptomatic prostatic enlargement: a risk-adaptive strategy for the era of active surveillance

OBJECTIVE

To investigate whether transurethral resection of the prostate can be used as both (i) treatment for symptomatic prostatic enlargement in patients with prostate cancer and (ii) a risk-adaptive strategy for reducing prostate-specific antigen levels and broadening the indications of active surveillance.

METHODS

We retrospectively reviewed data of 3680 patients who underwent prostate biopsies at a single institution (March 2006 to January 2012). Of 529 men who had Gleason score 6 prostate cancer and were ineligible for active surveillance, 86 (16.3%) underwent transurethral resection of the prostate for symptomatic prostatic enlargement. We assessed how changes in prostate-specific antigen and prostate-specific antigen density influenced the eligibility for active surveillance and the outcome of subsequent therapy. The following active surveillance criteria were used: prostate-specific antigen ≤ 10 ng/ml, prostate-specific antigen density ≤ 0.15, positive cores ≤ 3 and single core involvement ≤ 50%.

RESULTS

The median age, pre-operative prostate-specific antigen and prostate volume were 71 years, 6.95 ng/ml, and 45.8 g, respectively. In 82.6% (71/86) of analyzed cases, ineligibility for active surveillance had resulted from elevated prostate-specific antigen level or prostate-specific antigen density. With a median resection of 16.5 g, transurethral resection of the prostate reduced the percentage of prostate-specific antigen and the percentage of prostate-specific antigen density by 34.5 and 50.0%, respectively, making 81.7% (58/71) of the patients eligible for active surveillance. Prostate-specific antigen level remained stabilized in all (21/21) patients maintained on active surveillance without disease progression during the median follow-up of 50.6 months. Among patients who underwent radical prostatectomy, 96.7% (29/30) exhibited localized disease.

CONCLUSIONS

Risk-adaptive transurethral resection of the prostate may prevent overtreatment and allay prostate-specific antigen-associated anxiety in patients with biopsy-proven low-grade prostate cancer and elevated prostate-specific antigen. Additional benefits include voiding symptom improvement and the avoidance of curative therapy's immediate side effects.

Risk Algorithm Using Serial Biomarker Measurements Doubles the Number of Screen-Detected Cancers Compared With a Single-Threshold Rule in the United Kingdom Collaborative Trial of Ovarian Cancer Screening

PURPOSE

Cancer screening strategies have commonly adopted single-biomarker thresholds to identify abnormality. We investigated the impact of serial biomarker change interpreted through a risk algorithm on cancer detection rates.

PATIENTS AND METHODS

In the United Kingdom Collaborative Trial of Ovarian Cancer Screening, 46,237 women, age 50 years or older underwent incidence screening by using the multimodal strategy (MMS) in which annual serum cancer antigen 125 (CA-125) was interpreted with the risk of ovarian cancer algorithm (ROCA). Women were triaged by the ROCA: normal risk, returned to annual screening; intermediate risk, repeat CA-125; and elevated risk, repeat CA-125 and transvaginal ultrasound. Women with persistently increased risk were clinically evaluated. All participants were followed through national cancer and/or death registries. Performance characteristics of a single-threshold rule and the ROCA were compared by using receiver operating characteristic curves.

RESULTS

After 296,911 women-years of annual incidence screening, 640 women underwent surgery. Of those, 133 had primary invasive epithelial ovarian or tubal cancers (iEOCs). In all, 22 interval iEOCs occurred within 1 year of screening, of which one was detected by ROCA but was managed conservatively after clinical assessment. The sensitivity and specificity of MMS for detection of iEOCs were 85.8% (95% CI, 79.3% to 90.9%) and 99.8% (95% CI, 99.8% to 99.8%), respectively, with 4.8 surgeries per iEOC. ROCA alone detected 87.1% (135 of 155) of the iEOCs. Using fixed CA-125 cutoffs at the last annual screen of more than 35, more than 30, and more than 22 U/mL would have identified 41.3% (64 of 155), 48.4% (75 of 155), and 66.5% (103 of 155), respectively. The area under the curve for ROCA (0.915) was significantly (P = .0027) higher than that for a single-threshold rule (0.869).

CONCLUSION

Screening by using ROCA doubled the number of screen-detected iEOCs compared with a fixed cutoff. In the context of cancer screening, reliance on predefined single-threshold rules may result in biomarkers of value being discarded.

The optimal timing to perform 18F/11C-choline PET/CT in patients with suspicion of relapse of prostate cancer: trigger PSA versus PSA velocity and PSA doubling time

In the present short communication we considered the main publications focused on trigger prostate-specific antigen (PSA) and PSA kinetics that systematically compared 18F to 11C-choline PET/CT in order to establish the optimal time to perform choline PET/CT in relation to the trigger values and velocity, as well as doubling time of PSA serum levels.

Circulating biomarkers for discriminating indolent from aggressive disease in prostate cancer active surveillance

PURPOSE OF REVIEW

To review research on the use of circulating biomarkers to predict unfavorable tumor pathology in the setting of active surveillance, or in clinical contexts that are informative for active surveillance, such as men with low-risk prostate cancer evaluated for upgrading or upstaging at surgery.

RECENT FINDINGS

Biomarkers have been evaluated in serum, plasma, urine, and expressed prostatic secretions. Only a small number of biomarkers have been evaluated in multiple studies: %free prostate-specific antigen (PSA), PSA velocity, PSA doubling time, proPSA, PCA3, TMPRSS2-ERG. Single studies with relevance to active surveillance have evaluated microRNAs, circulating tumor cells, and exosomes. The most consistent significant associations with unfavorable tumor pathology have been with %free PSA. Associations with [-2]proPSA and Prostate Health Index have also been consistent; however, three of four studies come from the same active surveillance patient cohort.

SUMMARY

Circulating biomarkers represent a promising approach to identify men with apparently low-risk biopsy pathology, but who harbor potentially aggressive tumors unsuitable for active surveillance. Research is still at an early stage; existing biomarkers need rigorous validation with consistent methodology, and additional biomarkers need to be evaluated. Successful clinical translation would reduce the frequency of surveillance biopsies, and may enhance acceptance of active surveillance.

Associations of circulating 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and vitamin D pathway genes with prostate-specific antigen progression in men with localized prostate cancer undergoing active monitoring

Current diagnostic tests cannot differentiate the majority of prostate cancers with a low likelihood of progression from the minority with more aggressive potential. We examined whether the measures of vitamin D were associated with prostate-specific antigen (PSA) doubling time in men undergoing active monitoring. We examined the associations of circulating 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and vitamin D pathway polymorphisms with PSA doubling time in 490 men undergoing active monitoring for localized prostate cancer within a UK population-based cohort study [mean follow-up 4.4 years (range: 0.3-7.6)]. Repeat PSA measurements were analyzed using multilevel models. There was no evidence that circulating 25(OH)D levels, 1,25(OH)2D levels, or vitamin D pathway polymorphisms were associated with postdiagnosis PSA doubling time. Stratifying the results by prostate cancer grade at diagnosis (high grade or low grade) did not alter the results. We found no evidence that either circulating 25(OH)D, 1,25(OH)2D, or vitamin D pathway polymorphisms were associated with PSA doubling time in men undergoing active monitoring for localized prostate cancer. Future studies should examine the associations of variation in vitamin D with clinical outcomes (metastases and death).

Folate and B12 in prostate cancer

Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification.

Importance and determinants of Gleason score undergrading on biopsy sample of prostate cancer in a population-based study

Background

In this population-based study, we investigated the degree of concordance between Gleason scores obtained from prostate biopsies and those obtained from prostatectomy specimens, as well as the determinants of biopsy understaging.

Methods

We considered for this study all 371 prostate cancer patients recorded at the Geneva Cancer Registry diagnosed from 2004 to 2006 who underwent a radical prostatectomy. We used the kappa statistic to evaluate the Gleason score concordance from biopsy and prostatectomy specimens. Logistic regression was used to determine the parameters that predict the undergrading of the Gleason score in prostate biopsies.

Results

The kappa statistic between biopsy and prostatectomy Gleason score was 0.42 (p < 0.0001), with 67% of patients exactly matched, and 26% (n = 95) patients with Gleason score underestimated by the biopsy. In a multi-adjusted model, increasing age, advanced clinical stage, having less than ten biopsy cores, and longer delay between the two procedures, were all independently associated with biopsy undergrading. In particular, the proportion of exact match increased to 72% when the patients had ten or more needle biopsy cores. The main limitation of the study is that both biopsy and prostatectomy specimens were examined by different laboratories.

Conclusions

The data show that concordance between biopsy and prostatectomy Gleason scores lies within the classic clinical standards in this population-based study. The number of biopsy cores appears to strongly impact on the concordance between biopsy and radical prostatectomy Gleason score.

Personalized management in low-risk prostate cancer: the role of biomarkers

Current criteria to predict low-risk prostate cancer (PCa) are still subject to discussion as a substantial number of PCa patients who progress to a more aggressive disease seem to be missed, using these criteria. The main challenge in PCa diagnosis, therefore, is to distinguish patients with low-risk PCa who will show slow progression of disease from patients at risk for progression to a more aggressive cancer. The current discovered biomarkers could potentially guide in this management and improve detection, staging, and prognosis. This paper provides an overview of the current available serum-, urine-, and tissue-based biomarkers in PCa and evaluates the clinical usefulness of these biomarkers in the detection and management of low-risk PCa.

Role of active surveillance in the management of localized prostate cancer

Active surveillance is an increasingly recognized treatment option for men with low-risk prostate cancer. Despite encouraging evidence for oncologic efficacy and reduction in morbidity, several barriers contribute to the underuse of this management strategy. Consistent selection criteria as well as identification and validation of triggers for subsequent intervention are essential. Incorporation of novel biomarkers as well as advanced imaging techniques may improve surveillance strategies by better defining eligibility as well as improving prompt detection of disease progression.

Insulin-like growth factors (IGFs) and IGF-binding proteins in active monitoring of localized prostate cancer: a population-based observational study

PURPOSE

Active monitoring of prostate cancer requires the selection of low-risk cancers and subsequent identification of disease progression. Our objective was to determine whether serum insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein (IGFBP)-2 or IGFBP-3 at diagnosis (potential biomarkers of prognosis), and repeated measures of IGFBP-2 (potential biomarker of tumour growth), were associated with annual change in PSA and PSA doubling time (PSADT), proxies for disease progression.

METHODS

We investigated associations of circulating IGFs and IGFBPs with PSA measures using multilevel models, in 909 men (recruited between 1999 and 2009) with PSA-detected clinically localized prostate cancer undergoing active monitoring in the United Kingdom. Each man had an average of 14 measurements of PSA during a mean of 4-year follow-up.

RESULTS

IGF-I, IGF-II, IGFBP-2, and IGFBP-3 were not associated with baseline PSA. There was weak evidence that IGF-I at diagnosis was positively associated with a rapid post-diagnosis PSADT (≤4 years vs. >4 years): OR 1.34 (95 % CI 0.98, 1.81) per SD increase in IGF-I. IGFBP-2 increased by 2.1 % (95 % CI 1.4, 2.8) per year between 50 and 70 years, with no association between serial IGFBP-2 levels and PSADT. There was no evidence that serum IGF-II, IGFBP-2, or IGFBP-3, or post-diagnosis IGFBP-2, were associated with PSA kinetics in men with PSA-detected localized prostate cancer.

CONCLUSIONS

The weak association of IGF-I with PSADT requires replication in larger datasets, and more definitive evidence will be provided on the maturity of long-term active monitoring cohorts with relevant clinical outcomes (metastasis and prostate cancer mortality).

PSA Velocity and Doubling Time in Diagnosis and Prognosis of Prostate Cancer

Cancer is a growth process and it is natural that we should be concerned with how the routinely used marker of prostate cancer tumour burden - PSA - changes over time. Such change is measured by PSA velocity or PSA doubling time, described in general as "PSA kinetics". However, it turns out that calculation of PSA velocity and doubling time is far from straightforward. More than 20 different methods have been proposed, and many of these give quite divergent results. There is clear evidence that PSA kinetics are critical for understanding prognosis in advanced or relapsed prostate cancer. However, PSA kinetics have no value for men with an untreated prostate: neither PSA velocity nor doubling time have any role in diagnosing prostate cancer or providing a prognosis for men before treatment.

Differentiation of lethal and non lethal prostate cancer: PSA and PSA isoforms and kinetics

Prostate-specific antigen (PSA) testing for the early diagnosis of prostate cancer has led to a decrease in cancer mortality. However, the high prevalence of low-grade prostate cancer and its long natural history, competing causes of death in older men and treatment patterns of prostate cancer, have led to dramatic overtreatment of the disease. Improved markers of prostate cancer lethality are needed to reduce the overtreatment of prostate cancer that leads to a reduced quality of life without extending life for a high proportion of men. The PSA level prior to treatment is routinely used in multivariable models to predict prostate cancer aggressiveness. PSA isoforms and PSA kinetics have been associated with more aggressive phenotypes, but are not routinely employed as part of prediction tools prior to treatment. PSA kinetics is a valuable marker of lethality post treatment and routinely used in determining the need for salvage therapy.

Influence of PSA, PSA velocity and PSA doubling time on contrast-enhanced 18F-choline PET/CT detection rate in patients with rising PSA after radical prostatectomy

PURPOSE

To evaluate the accuracy of contrast-enhanced (18)F-choline PET/CT in restaging patients with prostate cancer after radical prostatectomy in relation to PSA, PSA velocity (PSAve) and PSA doubling time (PSAdt).

METHODS

PET/CT was performed in 49 patients (age range 58-87 years) with rising PSA (mean 4.13 ng/ml) who were divided in four groups according to PSA level: ≤1 ng/ml, 1 to ≤2 ng/ml, 2 to ≤4 ng/ml, and >4 ng/ml. PSAve and PSAdt were measured. PET and CT scans were interpreted separately and then together.

RESULTS

PET/CT diagnosed relapse in 33 of the 49 patients (67%). The detection rates were 20%, 55%, 80% and 87% in the PSA groups ≤1, 1 to ≤2, 2 to ≤4 and >4 ng/ml, respectively. PET/CT was positive in 7 of 18 patients (38.9%) with a PSA ≤2 ng/ml, and in 26 of 31 (83.9%) with a PSA >2 ng/ml. PET/CT was positive in 7 of 25 patients (84%) with PSAdt ≤6 months, and in 12 of 24 patients (50%) with PSAdt >6 months, and was positive in 26 of 30 patients (86%) with a PSAve >2 ng/ml per year, and in 7 of 19 patients (36.8%) with PSAve ≤2 ng/ml per year. PET alone was positive in 31 of 49 patients (63.3%), and of these 31 patients, CT was negative in 14 but diagnosed bone lesions in 2 patients in whom PET alone was negative. CT with the administration of intravenous contrast medium did not provide any further information.

CONCLUSION

Detection rate of (18)F-choline imaging is closely related to PSA and PSA kinetics. In particular, (18)F-choline PET/CT is recommended in patients with PSA >2 ng/ml, PSAdt ≤6 months and PSAve >2 ng/ml per year. CT is useful for detecting bone metastases that are not (18)F-choline-avid. The use of intravenous contrast agent seems unnecessary.

Role of prostate specific antigen and immediate confirmatory biopsy in predicting progression during active surveillance for low risk prostate cancer

PURPOSE

We evaluated predictors of progression after starting active surveillance, especially the role of prostate specific antigen and immediate confirmatory prostate biopsy.

MATERIALS AND METHODS

A total of 238 men with prostate cancer met active surveillance eligibility criteria and were analyzed for progression with time. Cox proportional hazards regression was used to evaluate predictors of progression. Progression was evaluated using 2 definitions, including no longer meeting 1) full and 2) modified criteria, excluding prostate specific antigen greater than 10 ng/ml as a criterion.

RESULTS

Using full criteria 61 patients progressed during followup. The 2 and 5-year progression-free probability was 80% and 60%, respectively. With prostate specific antigen included in progression criteria prostate specific antigen at confirmatory biopsy (HR 1.29, 95% CI 1.14-1.46, p <0.0005) and positive confirmatory biopsy (HR 1.75, 95% CI 1.01-3.04, p = 0.047) were independent predictors of progression. Of the 61 cases 34 failed due to increased prostate specific antigen, including only 5 with subsequent progression by biopsy criteria. When prostate specific antigen was excluded from progression criteria, only 32 cases progressed, and 2 and 5-year progression-free probability was 91% and 76%, respectively. Using modified criteria as an end point positive confirmatory biopsy was the only independent predictor of progression (HR 3.16, 95% CI 1.41-7.09, p = 0.005).

CONCLUSIONS

Active surveillance is feasible in patients with low risk prostate cancer and most patients show little evidence of progression within 5 years. There is no clear justification for treating patients in whom prostate specific antigen increases above 10 ng/ml in the absence of other indications of tumor progression. Patients considering active surveillance should undergo confirmatory biopsy to better assess the risk of progression.

Relationship between initial PSA density with future PSA kinetics and repeat biopsies in men with prostate cancer on active surveillance

The objective of our study is to examine the correlation between PSA density (PSAd) at the time of diagnosis with PSA velocity (PSAV), PSA doubling time and tumour progression, on repeat biopsy, in men with prostate cancer on active surveillance. Data from 102 patients with clinically localized prostate cancer on active surveillance in the period between 1992 and 2007, who had the necessary parameters available, were collected. PSAd was calculated and correlated with PSAV, PSA doubling time (PSADT), Gleason score at diagnosis and local progression on repeated biopsies. PSAV was 0.64 and 1.31 ng ml^–1 per year (P=0.02), PSADT of 192 and 113 months (P=0.4) for PSAd below and above 0.15, respectively. The rate of detecting high Gleason score (⩾7) at diagnosis was 6 and 23% for PSAd below and above 0.15, respectively. A total of 101 patients underwent at least a second biopsy and the incidence of upgrading was 10 and 31% for PSAd below and above 0.15, respectively (P=0.001). Although low PSAd is an accepted measure for suggesting insignificant prostate cancer, our study expands its role to indicate that PSAd <0.15 may be an additional clinical parameter that may suggest indolent disease, as measured by future PSAV and repeat biopsy over time.

Prostate cancer managed with active surveillance: role of anatomic MR imaging and MR spectroscopic imaging

PURPOSE

To determine the role that magnetic resonance (MR) imaging and MR spectroscopic imaging findings obtained at the time of diagnosis play in the progression of disease in patients whose prostate cancer is being managed with active surveillance and to compare the role of these findings with the role of transrectal ultrasonography (US) findings.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant retrospective study, and informed consent was obtained from all patients whose records were to be entered into the research database. All patients who had prostate cancer managed with active surveillance and who had undergone both MR imaging and MR spectroscopic imaging of the prostate and transrectal US at time of diagnosis were identified. Two urologists blinded to the clinical outcome in these patients independently reviewed and dichotomized the MR imaging report and the MR spectroscopic imaging report as normal or suggestive of malignancy. One experienced urologist performed all US examinations that were then dichotomized similarly. Uni- and multivariate (with use of standard clinical variables) Cox models were fitted to assess time to cancer progression, defined as Gleason score upgrading, prostate-specific antigen velocity of more than 0.75 (microg x L(-1))/y, or initiation of treatment more than 6 months after diagnosis.

RESULTS

The final cohort included 114 patients with a median follow-up of 59 months. Patients with a lesion that was suggestive of cancer at MR imaging had a greater risk of the Gleason score being upgraded at subsequent biopsy (hazard ratio, 4.0; 95% confidence interval: 1.1, 14.9) than did patients without such a lesion. Neither MR spectroscopic imaging nor transrectal US could be used to predict cancer progression.

CONCLUSION

Abnormal prostate MR imaging results suggestive of cancer may confer an increased risk of Gleason score upgrade at subsequent biopsy. Although expensive, prostate MR imaging may help in counseling potential candidates about active surveillance.

Is delayed radical prostatectomy in men with low-risk screen-detected prostate cancer associated with a higher risk of unfavorable outcomes?

BACKGROUND

Strategies of active surveillance (AS) of low-risk screen-detected prostate cancer have emerged, because the balance between survival outcomes and quality of life issues when radically treating these malignancies is disputable. Delay before radical treatment caused by active surveillance may be associated with an impaired chance of curability.

METHODS

Men diagnosed with low-risk (T1c/T2; prostate-specific antigen [PSA] = <10.0; PSA density, <0.2 ng/mL; Gleason score, 3 + 3=6; 1-2 positive biopsies) prostate cancer in the Swedish section of the European Randomized Study of Screening for Prostate Cancer who received radical prostatectomy (RP) were studied. One group received immediate RP, whereas another group received delayed RP after an initial period of expectant management. These groups were compared regarding histopathological and biochemical outcomes, correcting for baseline differences.

RESULTS

Mean follow-up after diagnosis was 5.7 years (standard deviation [SD], 3.2). The immediate RP group (n = 158) received RP a mean of 0.5 (SD, 0.2) years after diagnosis; the delayed RP group (n = 69) received RP after 2.6 (SD, 2.0) years (P < .001). After adjustment for small baseline dissimilarities, no differences in RP frequencies of Gleason score >6 (odds ratio [OR], 1.54; P = .221), capsular penetration (OR, 2.45; P = .091), positive margins (OR, 1.34; P = .445), RP tumor volume (difference, 0.099; P = .155), or biochemical progression rates (P = .185, P = .689) were found between groups, although all data were in favor of immediate RP.

CONCLUSIONS

With limited patient numbers available for analysis, differences in intermediate outcomes between immediate RP and delayed RP were nonsignificant. The delayed RP group may be subject to a selection bias. Prospective evaluation of active surveillance protocols is essential.

Radical prostatectomy findings in patients in whom active surveillance of prostate cancer fails

PURPOSE

Little data are available on radical prostatectomy findings in men who experience disease progression following active surveillance.

MATERIALS AND METHODS

A total of 470 men in our active surveillance program underwent annual repeat needle biopsies to look for progression defined as any Gleason pattern grade 4/5, more than 50% cancer on any core or cancer in more than 2 cores. Slides were available for review in 48 of 51 radical prostatectomies with progression.

RESULTS

The average time between the first prostate biopsy and radical prostatectomy was 29.5 months (range 13 to 70), with 44% and 75% of the patients showing progression by the second and third biopsy, respectively. There were 31 (65%) organ confined cases, of which 25 (52%) were Gleason score 6. Of 48 cases 17 (35%) had extraprostatic extension, 3 had seminal vesicle/lymph node involvement and 7 (15%) had positive margins. Mean total tumor volume was 1.3 cm(3) (range 0.02 to 10.8). Of the 48 tumors 13 (27%) were potentially clinically insignificant (organ confined, dominant nodule less than 0.5 cm(3), no Gleason pattern 4/5) and 19% (5 of 26) of the radical prostatectomies with a dominant tumor nodule less than 0.5 cm(3) demonstrated extraprostatic extension, 4 with Gleason pattern 4. All 10 tumors with a dominant nodule greater than 1 cm(3) were located predominantly anteriorly.

CONCLUSIONS

Most progression after active surveillance occurs 1 to 2 years after diagnosis suggesting undersampling of more aggressive tumor rather than progression of indolent tumor. Even with progression most tumors have favorable pathology (27% potentially insignificant). A small percentage of men have advanced stage disease (pT3b or N1). The anterior region should be sampled in men on active surveillance.

Current strategies for monitoring men with localised prostate cancer lack a strong evidence base: observational longitudinal study

Background:

The UK National Institute for Health and Clinical Excellence (NICE) guidance recommends conservative management of men with ‘low-risk’ localised prostate cancer, monitoring the disease using prostate-specific antigen (PSA) kinetics and re-biopsy. However, there is little evidence of the changes in PSA level that should alert to the need for clinical re-assessment.

Methods:

This study compares the alerts resulting from PSA kinetics and a novel longitudinal reference range approach, which incorporates age-related changes, during the monitoring of 408 men with localised prostate cancer. Men were monitored by regular PSA tests over a mean of 2.9 years, recording when a man's PSA doubling time fell below 2 years, PSA velocity exceeded 2 ng ml^–1 per year, or when his upper 10% reference range was exceeded.

Results:

Prostate-specific antigen doubling time and PSA velocity alerted a high proportion of men initially but became unresponsive to changes with successive tests. Calculating doubling time using recent PSA measurements reduced the decline in response. The reference range method maintained responsiveness to changes in PSA level throughout the monitoring.

Conclusion:

The increasing unresponsiveness of PSA kinetics is a consequence of the underlying regression model. Novel methods are needed for evaluation in cohorts currently being managed by monitoring. Meanwhile, the NICE guidance should be cautious.

Role of PSA velocity in predicting pathologic upgrade for Gleason 6 prostate cancer

BACKGROUND

Pathologic upgrading to Gleason 7 or higher on radical prostatectomy (RP) specimens occurs in many patients with Gleason 6 prostate cancer on preoperative biopsy. We evaluated whether biopsy characteristics and preoperative factors, including preoperative PSA velocity (PSAV), are predictive of pathologic upgrading.

MATERIALS AND METHODS

We identified 235 consecutive Gleason 6 prostate cancer patients who underwent biopsies at our institution, had multiple pre-biopsy PSA values, and eventually underwent RP. Preoperative biopsy, clinical characteristics, and PSAV were analyzed to determine the risk of pathologic upgrading or extracapsular extension. These clinical factors were evaluated for association with biochemical recurrence following RP.

RESULTS

Overall, 48% of patients were upgraded to Gleason grade 7 or higher following RP. Median PSAV was 0.61 ng/mL/y, and PSAV was similar between upgraded and non-upgraded patients (1.01 vs. 0.78, P = 0.1). PSA velocity level was not associated with extracapsular disease (P = 0.4). PSA velocity > 1 was associated with biochemical recurrence (HR 3.23, P = 0.01) but this was not statistically significant in a multivariable model. Increasing PSA density (HR 2.18, P < 0.001), bilateral cores positive (HR 1.89, P < 0.05), and any biopsy core involvement > 50% (HR 2.52, P < 0.05) were most associated with pathologic upgrading. On multivariate analysis, only bilateral cancer detection at biopsy (HR 1.90, P < 0.05) significantly predicted upgrading.

CONCLUSIONS

PSAV has a limited role in predicting Gleason 6 upgrading. Patients with bilateral cancer detected on transrectal biopsy should be encouraged to have radical local therapy due to high risk of harboring more aggressive disease.

Insignificant prostate cancer and active surveillance: from definition to clinical implications

CONTEXT

Due to early detection strategies, prostate cancer is diagnosed early in its natural history. It remains unclear whether all patients diagnosed with prostate cancer warrant radical treatment or may benefit from delayed intervention following active surveillance.

OBJECTIVE

A systematic review of active surveillance protocols to investigate the inclusion criteria for active surveillance and the outcome of treatment.

EVIDENCE ACQUISITION

Medline was searched using the following terms: prostate cancer, active surveillance and expectant management for dates up to October 2008. Further studies were chosen on the basis of manual searches of reference lists and review papers.

EVIDENCE SYNTHESIS

Numerous studies on active surveillance were identified. The recent inclusion criteria of the studies are rather similar. Keeping the short follow-up of all studies in mind, the majority of men stay on active surveillance, and the percentage of patients receiving active treatment is as high as 35% of all patients. Once a patients requires active treatment, most patients still present with curable prostate cancer. Furthermore, only few deaths due to prostate cancer have occurred.

CONCLUSIONS

Active surveillance is an alternative option to immediate treatment of men with presumed insignificant prostate cancer. It seems that criteria used to identify men with low-risk prostate cancer are rather similar, and immediate treatment of men meeting these criteria may result in an unnecessary number of treatments in these highly selected patients. Data from randomised trials comparing active surveillance and active treatment will provide additional insight into outcome and follow-up strategies.