Detection of prostate cancer in unselected young men: prospective cohort nested within a randomised controlled trial

[Risk-adapted prostate cancer screening-update 2021]

BACKGROUND

Prostate cancer (PCa) is the most common cancer and the second leading cause of cancer death in men in industrialized countries. There is no commonly accepted prostate cancer screening strategy. Based on the experience of various international screening studies, the German Prostate Cancer Early Detection Study Based on a Baseline PSA Value in Young Men (PROBASE) was established in 2014.

OBJECTIVE

Based on the positive results of retrospective cohort analyses, the PROBASE study is designed to demonstrate that a screening strategy based on risk stratification by a baseline prostate-specific antigen (PSA) level at age 45 or 50 years may be an alternative to population-based screening. PROBASE is presented in the context of other risk-adapted screening studies.

MATERIALS AND METHODS

There are basically several approaches to improve the population-based screening of PCa. Known risk factors for prostate cancer are age, a certain genetic predisposition (BRCA 1/2) and other germline mutations as well as individual somatic mutations.

RESULTS

A total of 23,301 participants were randomized to study arm A. Baseline PSA testing in study arm A categorized 89.18% of participants into the low-risk group, 9.32% into the intermediate-risk group, and 1.48% into the high-risk group. Thus, the risk assignment exactly matched the previously reported distribution.

DISCUSSION

Baseline PSA-dependent, risk-adapted PSA screening has the potential to reduce the high incidence of overdiagnosis and ultimately overtreatment of insignificant prostate cancers of population-based screening through extended testing intervals in the low-risk group. In parallel with PROBASE, several risk-adapted screening strategies are currently being tested worldwide; the evaluation of which is also awaited in several years.

Active monitoring, radical prostatectomy and radical radiotherapy in PSA-detected clinically localised prostate cancer: the ProtecT three-arm RCT

BACKGROUND

Prostate cancer is the most common cancer among men in the UK. Prostate-specific antigen testing followed by biopsy leads to overdetection, overtreatment as well as undertreatment of the disease. Evidence of treatment effectiveness has lacked because of the paucity of randomised controlled trials comparing conventional treatments.

OBJECTIVES

To evaluate the effectiveness of conventional treatments for localised prostate cancer (active monitoring, radical prostatectomy and radical radiotherapy) in men aged 50-69 years.

DESIGN

A prospective, multicentre prostate-specific antigen testing programme followed by a randomised trial of treatment, with a comprehensive cohort follow-up.

SETTING

Prostate-specific antigen testing in primary care and treatment in nine urology departments in the UK.

PARTICIPANTS

Between 2001 and 2009, 228,966 men aged 50-69 years received an invitation to attend an appointment for information about the Prostate testing for cancer and Treatment (ProtecT) study and a prostate-specific antigen test; 82,429 men were tested, 2664 were diagnosed with localised prostate cancer, 1643 agreed to randomisation to active monitoring (n = 545), radical prostatectomy (n = 553) or radical radiotherapy (n = 545) and 997 chose a treatment.

INTERVENTIONS

The interventions were active monitoring, radical prostatectomy and radical radiotherapy.

TRIAL PRIMARY OUTCOME MEASURE

Definite or probable disease-specific mortality at the 10-year median follow-up in randomised participants.

SECONDARY OUTCOME MEASURES

Overall mortality, metastases, disease progression, treatment complications, resource utilisation and patient-reported outcomes.

RESULTS

There were no statistically significant differences between the groups for 17 prostate cancer-specific (p = 0.48) and 169 all-cause (p = 0.87) deaths. Eight men died of prostate cancer in the active monitoring group (1.5 per 1000 person-years, 95% confidence interval 0.7 to 3.0); five died of prostate cancer in the radical prostatectomy group (0.9 per 1000 person-years, 95% confidence interval 0.4 to 2.2 per 1000 person years) and four died of prostate cancer in the radical radiotherapy group (0.7 per 1000 person-years, 95% confidence interval 0.3 to 2.0 per 1000 person years). More men developed metastases in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring, n = 33 (6.3 per 1000 person-years, 95% confidence interval 4.5 to 8.8); radical prostatectomy, n = 13 (2.4 per 1000 person-years, 95% confidence interval 1.4 to 4.2 per 1000 person years); and radical radiotherapy, n = 16 (3.0 per 1000 person-years, 95% confidence interval 1.9 to 4.9 per 1000 person-years; p = 0.004). There were higher rates of disease progression in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring (n = 112; 22.9 per 1000 person-years, 95% confidence interval 19.0 to 27.5 per 1000 person years); radical prostatectomy (n = 46; 8.9 per 1000 person-years, 95% confidence interval 6.7 to 11.9 per 1000 person-years); and radical radiotherapy (n = 46; 9.0 per 1000 person-years, 95% confidence interval 6.7 to 12.0 per 1000 person years; p < 0.001). Radical prostatectomy had the greatest impact on sexual function/urinary continence and remained worse than radical radiotherapy and active monitoring. Radical radiotherapy's impact on sexual function was greatest at 6 months, but recovered somewhat in the majority of participants. Sexual and urinary function gradually declined in the active monitoring group. Bowel function was worse with radical radiotherapy at 6 months, but it recovered with the exception of bloody stools. Urinary voiding and nocturia worsened in the radical radiotherapy group at 6 months but recovered. Condition-specific quality-of-life effects mirrored functional changes. No differences in anxiety/depression or generic or cancer-related quality of life were found. At the National Institute for Health and Care Excellence threshold of £20,000 per quality-adjusted life-year, the probabilities that each arm was the most cost-effective option were 58% (radical radiotherapy), 32% (active monitoring) and 10% (radical prostatectomy).

LIMITATIONS

A single prostate-specific antigen test and transrectal ultrasound biopsies were used. There were very few non-white men in the trial. The majority of men had low- and intermediate-risk disease. Longer follow-up is needed.

CONCLUSIONS

At a median follow-up point of 10 years, prostate cancer-specific mortality was low, irrespective of the assigned treatment. Radical prostatectomy and radical radiotherapy reduced disease progression and metastases, but with side effects. Further work is needed to follow up participants at a median of 15 years.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN20141297.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 37. See the National Institute for Health Research Journals Library website for further project information.

Evaluation of an Aggressive Prostate Biopsy Strategy in Men Younger than 50 Years

PURPOSE

Longitudinal cohort studies and guidelines demonstrate that prostate specific antigen 1 ng/ml or greater in younger patients confers an increased risk of delayed prostate cancer death. At our institution we have used an aggressive biopsy strategy in younger patients with prostate specific antigen 1 ng/ml or greater. Our objective was to determine the proportion of detected cancer and specifically clinically significant cancer by this strategy.

MATERIALS AND METHODS

The prostate biopsy database at Princess Margaret Cancer Centre was queried for patients younger than 50 years who underwent a first prostate biopsy between 2000 and 2016. We included only patients who underwent prostate biopsy due to prostate specific antigen 1 ng/ml or greater and those with a suspicious digital rectal examination, a positive family history or a suspicious lesion on transrectal ultrasound. All clinical and pathological parameters were analyzed. Patients were stratified according to specific prostate specific antigen values. Multivariable logistic regression was performed to ascertain predictors of any prostate cancer diagnosis and of clinically significant prostate cancer.

RESULTS

Of the 199 patients who met study inclusion criteria 37 (19%) were diagnosed with prostate cancer and 8 (22%) had a Gleason score of 7 or greater. Of those diagnosed with prostate cancer 25 (68%) had prostate specific antigen 1.5 ng/ml or greater and all men with a Gleason score of 7 or greater had prostate specific antigen 1.5 ng/ml or greater. Notably 19 patients (51%) had prostate cancer exceeding the Epstein criteria for active surveillance. Factors predicting prostate cancer included a positive family history, rising prostate specific antigen and lower prostate volume.

CONCLUSIONS

Our results justify adopting an aggressive prostate biopsy strategy in men younger than 50 years with prostate specific antigen 1.5 ng/ml or greater while patients with prostate specific antigen less than 1.5 ng/ml are unlikely to have significant cancer. Special attention should be given to patients with a smaller prostate and a positive family history.

Ablative therapy for people with localised prostate cancer: a systematic review and economic evaluation

BACKGROUND

For people with localised prostate cancer, active treatments are effective but have significant side effects. Minimally invasive treatments that destroy (or ablate) either the entire gland or the part of the prostate with cancer may be as effective and cause less side effects at an acceptable cost. Such therapies include cryotherapy, high-intensity focused ultrasound (HIFU) and brachytherapy, among others.

OBJECTIVES

This study aimed to determine the relative clinical effectiveness and cost-effectiveness of ablative therapies compared with radical prostatectomy (RP), external beam radiotherapy (EBRT) and active surveillance (AS) for primary treatment of localised prostate cancer, and compared with RP for salvage treatment of localised prostate cancer which has recurred after initial treatment with EBRT.

DATA SOURCES

MEDLINE (1946 to March week 3, 2013), MEDLINE In-Process & Other Non-Indexed Citations (29 March 2013), EMBASE (1974 to week 13, 2013), Bioscience Information Service (BIOSIS) (1956 to 1 April 2013), Science Citation Index (1970 to 1 April 2013), Cochrane Central Register of Controlled Trials (CENTRAL) (issue 3, 2013), Cochrane Database of Systematic Reviews (CDSR) (issue 3, 2013), Database of Abstracts of Reviews of Effects (DARE) (inception to March 2013) and Health Technology Assessment (HTA) (inception to March 2013) databases were searched. Costs were obtained from NHS sources.

REVIEW METHODS

Evidence was drawn from randomised controlled trials (RCTs) and non-RCTs, and from case series for the ablative procedures only, in people with localised prostate cancer. For primary therapy, the ablative therapies were cryotherapy, HIFU, brachytherapy and other ablative therapies. The comparators were AS, RP and EBRT. For salvage therapy, the ablative therapies were cryotherapy and HIFU. The comparator was RP. Outcomes were cancer related, adverse effects (functional and procedural) and quality of life. Two reviewers extracted data and carried out quality assessment. Meta-analysis used a Bayesian indirect mixed-treatment comparison. Data were incorporated into an individual simulation Markov model to estimate cost-effectiveness.

RESULTS

The searches identified 121 studies for inclusion in the review of patients undergoing primary treatment and nine studies for the review of salvage treatment. Cryotherapy [3995 patients; 14 case series, 1 RCT and 4 non-randomised comparative studies (NRCSs)], HIFU (4000 patients; 20 case series, 1 NRCS) and brachytherapy (26,129 patients; 2 RCTs, 38 NRCSs) studies provided limited data for meta-analyses. All studies were considered at high risk of bias. There was no robust evidence that mortality (4-year survival 93% for cryotherapy, 99% for HIFU, 91% for EBRT) or other cancer-specific outcomes differed between treatments. For functional and quality-of-life outcomes, the paucity of data prevented any definitive conclusions from being made, although data on incontinence rates and erectile dysfunction for all ablative procedures were generally numerically lower than for non-ablative procedures. The safety profiles were comparable with existing treatments. Studies reporting the use of focal cryotherapy suggested that incontinence rates may be better than for whole-gland treatment. Data on AS, salvage treatment and other ablative therapies were too limited. The cost-effectiveness analysis confirmed the uncertainty from the clinical review and that there is no technology which appears superior, on the basis of current evidence, in terms of average cost-effectiveness. The probabilistic sensitivity analyses suggest that a number of ablative techniques are worthy of further research.

LIMITATIONS

The main limitations were the quantity and quality of the data available on cancer-related outcomes and dysfunction.

CONCLUSIONS

The findings indicate that there is insufficient evidence to form any clear recommendations on the use of ablative therapies in order to influence current clinical practice. Research efforts in the use of ablative therapies in the management of prostate cancer should now be concentrated on the performance of RCTs and the generation of standardised outcomes.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002461.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

High fat-induced obesity associated with insulin-resistance increases FGF-2 content and causes stromal hyperplasia in rat ventral prostate

Obesity affects sex hormone secretion, which can negatively influence prostatic structure, homeostasis, and disease. This investigation aimed to evaluate the repercussions of obesity induced by a high-fat diet on the rat prostate, with or without treatment with the aromatase inhibitor, Letrozole. Adult Wistar rats were fed a high-fat diet (20% saturated fat, O) for 15 weeks to induce obesity or received a balanced diet (4% fat, C). Then, a group of C and O rats were daily treated with Letrozole (1 mg/kg b.w. per day) for 2 weeks (CL and OL, respectively). Subsequently, ventral prostate was processed for analysis by transmission electron microscopy, immunohistochemistry, and Western blotting. Obesity decreased 70% of the testosterone plasma level. The prostate showed epithelial atrophy and dilated acini in the intermediate portion and epithelial wrinkling in the distal tips. The relative frequency of smooth muscle α-actin in the O group increased by 67%. Ultrastructurally, epithelial cells in obese animals presented altered secretory organelles, lipid droplets, and thicker subjacent fibromuscular layer. Letrozole treatment caused a partial restoration of the prostatic changes caused by obesity. Obesity increased the prostatic content of fibroblast growth factor-2 (FGF-2) by 150%, and Letrozole treatment increased this protein even more in the control and obese groups. This investigation shows that obesity provokes structural and ultrastructural changes in the epithelium of rat prostate; these changes might affect gland homeostasis and physiology. The epithelial and smooth muscle cell hyperplasia and increased FGF-2 expression observed in this experimental model of obesity/insulin-resistance might explain the high frequency of benign prostatic hyperplasia in insulin-resistant men.

Characteristics of baseline PSA and PSA velocity in young men without prostate cancer: Racial differences

BACKGROUND

Baseline prostate specific antigen (PSA) and PSA velocity used to stratify subsequent prostate cancer risk in young men may not directly applicable to all populations. We sought to compare the baseline PSA and PSA velocity among ethnic groups.

PATIENTS AND METHODS

Chinese, African-American (AA), and Caucasian-American (CA) men aged ≤50 years old without prostate cancer were used to identify baseline PSA and PSA velocity. The differences of baseline PSA and PSA velocity between races were assessed. The important cutoffs of baseline PSA and PSA velocity were used to stratify patients among races.

RESULTS

Four thousand two hundred six Chinese, 997 AA, and 2,030 CA were included. The rates of baseline PSA of ≥1.0, ≥2.5, and ≥4.0 ng/ml was 24.4%, 4.2%, and 2.1% in Chinese, 30.7%, 5.2%, and 1.8% in AA, 29.7%, 5.3%, and 2.8% in CA, respectively. The rates of PSA velocity of ≥0.35, ≥0.75, and ≥1.0 ng/ml/year was 6.0%, 3.1%, and 2.6% in Chinese, 5.3%, 2.3%, and 1.7% in AA, 5.4%, 3.5%, and 3.3% in CA, respectively. Chinese had a lower baseline PSA and higher PSA velocity as compared to AA and CA. Baseline PSA and PSA velocity in AA had no statistical differences as compared to CA.

CONCLUSIONS

The distributions of baseline PSA and PSA velocity in young men among Chinese, AA, and CA races are different. These characteristics shall be taken into account when using these variables to stratify risk of prostate cancer in young men.

Latest results from the UK trials evaluating prostate cancer screening and treatment: the CAP and ProtecT studies

The European Randomised Study of Screening for Prostate Cancer (ERSPC) demonstrated a significant reduction in prostate cancer-specific mortality. The ongoing Comparison Arm for ProtecT (CAP) cluster randomised controlled trial (RCT) evaluates prostate cancer screening effectiveness by comparing primary care centres allocated to a round of prostate specific antigen (PSA) testing (intervention) or standard clinical care. Over 550 centres (around 450,000 men) were randomised in eight United Kingdom areas (2002-2008). Intervention group participants were also eligible for the ProtecT (Prostate testing for cancer and Treatment) RCT evaluating active monitoring, radiotherapy and radical prostatectomy treatments for localised prostate cancer. In ProtecT, over 1500 of around 3000 men with prostate cancer were randomised from over 10,000 with an elevated PSA in around 111,000 attendees at clinics. Investigation of the psychological impact of screening in a sub-sample showed that 10% of men still experienced high distress up to 3 months following prostate biopsies (22/227), although most were relatively unaffected. The risk of prostate cancer with a raised PSA was lower if urinary symptoms were present (frequent nocturia odds ratio (OR) 0.44, 95% confidence interval (CI) 0.22-0.83) or if a repeat PSA decreased by > or = 20% prior to biopsy (OR 0.43, 95% CI 0.35-0.52). Men aged 45-49 years attended PSA clinics less frequently (442/1299, 34%) in a nested cohort with a cancer detection rate of 2.3% (10/442). The CAP and ProtecT trials (ISRCTN92187251 and ISRCTN20141217) will help resolve the prostate cancer screening debate, define the optimum treatment for localised disease and generate evidence to improve men's health.

Radical prostatectomy versus watchful waiting for prostate cancer

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Prostate cancer prevention by short-term anti-androgens: the rationale behind design of pilot studies

This paper sets out to review evidence that low-grade prostate inflammation is a precursor of prostate cancer development and the mechanisms by which it may account for the more than 50 years natural history from first infection to cancer. Though as yet there is no clear-cut specific associated infection, there is clear evidence that some sexually acquired infections damage the prostate and increase serum PSA with slow recovery back to normal. The demonstration that low-level solar exposure is protective provides a possible mechanism due to vitamin D's known benefit through action to boost macrophage-mediated immune surveillance. This observation and data demonstrating that non-steroidal anti-inflammatory drugs (NSAIDs) protect against prostate cancer provide the justification for trials of these two agents combined with short course intermittent anti-androgen therapy in populations at high risk of prostate cancer.

Prostate-specific antigen and prostate cancer: prediction, detection and monitoring

Testing for prostate-specific antigen (PSA) has profoundly affected the diagnosis and treatment of prostate cancer. PSA testing has enabled physicians to detect prostate tumours while they are still small, low-grade and localized. This very ability has, however, created controversy over whether we are now diagnosing and treating insignificant cancers. PSA testing has also transformed the monitoring of treatment response and detection of disease recurrence. Much current research is directed at establishing the most appropriate uses of PSA testing and at developing methods to improve on the conventional PSA test.

Screening for prostate cancer in younger men

Clinicians should promote informed decision making while awaiting definitive evidence from RCTs