Home > Information for doctors >Tutorials > Prostate Tutorial

Author: Francisco Machado
Date: 13/09/2000
Feedback: fran@abersychan.demon.co.uk

Contents:

Cases for discussion.

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Prostate cancer.

Prostate cancer is the second commonest cause of cancer related death in men. The main questions relating to this condition are:

·        Should we screen for prostate cancer?

·        What is the most effective treatment for “early” disease?

  These are important questions that the GP will be asked by patients attending on a regular basis.

  Screening for prostate cancer.

  The NHS Centre for Reviews and Dissemination based at the University of York published a review in 1997 as one of it’s Effective Matters Bulletins.

Screening for Prostate Cancer. Effective Matters. NHS Centre for Reviews and Dissemination, The University of York. Vol. 2, Issue 2, February 1997

 Some of it’s findings are presented below.

·        The aim of screening is to identify, at an early stage, those cases of prostate cancer, which will become invasive and then to offer treatment, which will increase the quality and length of life.

·        Unlike breast cancer screening, which has been shown to reduce mortality, prostate cancer screening has not yet been evaluated and there are several reasons why it may be less effective.

·        Many men with prostate cancer never experience any ill effects because some tumours are slow growing and not aggressive.

·        The most sensitive screening tests for prostate cancer are based on levels of prostate specific antigen (PSA). However, the PSA test and follow up biopsies cannot predict reliably whether a man has a cancer that will progress to cause ill health or death.

·        There have been no reliable evaluations of the effect of treatments for early prostate cancer on mortality. Active treatments can result in major complications such as incontinence and impotence.

·        There is no evidence on the number of deaths (if any), which could be averted by screening asymptomatic men. Screening may lead to physical and psychological harm resulting from testing, biopsy and treatment. It is not known whether screening for prostate cancer does more good than harm.

·        Routine testing of men to detect prostate cancer should be discouraged, irrespective of family history.

The US National Cancer Institute in its PDQ on screening for cancer of the prostate summarises the evidence as demonstrating:

“insufficient evidence to establish whether a decrease in mortality from prostate cancer occurs with screening by digital rectal examination, transrectal ultrasound, or serum markers including prostate-specific antigen.”

The findings of the NCI can be found on it’s website CancerNet that is regularly update and an excellent resource for cancer related problems for health professionals and patients. Website address http://cancernet.nci.nih.gov/index.html

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What’s wrong with PSA?

  PSA has many features that would make it an acceptable screening method:

·        Simple

·        Objective

·        Reproductive (although there is about 30% variation in levels in the same patient)

·        Non invasive

·        Lost cost when compared with ultrasound

  It’s sensitivity is about 70% with a positive predictive value that varies between 20-40%, the latter being highly dependant on the background prevalence which is age related. Two thirds to three quarters of asymptomatic men with a high PSA will be subsequently be shown not to have cancer.

PSA is raised in:

·        Increasing age

·        Blacks

·        BPH

·        Prostatitis

PSA is decreased by finasteride and so it should be checked prior to starting on treatment.

It is not affected by DRE.

Sexual intercourse may reduce PSA level in young men and may increase it in older men e.g. > 45 years.  (Bandolier May 1998) ? advise men to abstain from SI for 5 days prior to SI.

In the future PSA as a screening test may be improved by:

·        Age specific

·        Ratio to gland size

·        Ratio of free to bound

But all methods need further evaluation.

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Treatment of early cancer?

The options for treatment of early cancer of the prostate have formed the basis of three recent BMJ editorials.

Prior T, Waxman J.  Localised prostate cancer: can we do better? BMJ 2000; 320: 69-70.

Emberton M. What urologists say they do for men with prostate cancer BMJ 1999; 318: 276-276.G

Mulley AG, Barry MJ. Controversy in managing patients with prostate cancer. BMJ 1998; 316:1919-1920.

All three discuss the options for treatment as:

·        Watchful waiting with treatment only when disease progresses

·        Radical prostatectomy

·        Radiotherapy

The most recent editorial discusses the following:

·        Survival rates for poorly differentiated localised tumours are higher with radical surgery when compared to radiotherapy, but this may be due to selection bias in that patients offered surgery may be younger and fitter.

·        There is no difference between survival rates in moderate to well differentiated tumours with watchful waiting and radiotherapy

·        Due to the high relapse rate after 10 years in patients treated with conventional radiotherapy, attempts have been made to intensify radiotherapy treatment and the use of hormonal adjuvant treatment.

·        Antiandrogen therapy as adjuvant therapy has been shown to improve local disease but it is unclear if they alter overall survival

·        It is unclear which patients should be selected for treatment with adjuvant therapy and for how long. Also the significant side effects e.g. flushes, decreased libido need to be discussed with the patient.

A previous editorial looked at how urologists manage their patients. Essentially urologists tend to:

·        Offer radical surgery to younger patients

·        Offer radiotherapy to older patients e.g. > 75 years

Radical treatment, by hopefully increasing the chance of cure is being reserved for patients who have a life expectancy of greater than 10 years. But increased survival from radical surgery results in having to live with increased morbidity from that surgery for longer. However age alone is not a good predictor of outcome, co-morbidity seems more important.

Bandolier reported on the Prostate Outcomes Study looking at the incidence of urinary incontinence and sexual dysfunction in men who had a radical prostatectomy for localised prostate cancer. Questionnaires were sent to men 6, 12 and 24 months after surgery and were asked detail questions about sexual dysfunction and urinary incontinence. The study found high incidence of significant morbidity at six months but there seemed to be improvement particularly in urinary incontinence. However just over 40% of men reported a “moderate-to-big problem” with sexual dysfunction.

What happens after prostate cancer surgery? Bandolier March 2000; 73-6.

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Benign Prostatic Hyperplasia

A simple symptom index has been drafted by the American Urologists Association (AUA). By answering seven questions about the severity of symptoms, it is possible to define whether the symptoms are mild (0-7 points), moderate (8-19 points) or severe (20-35 points).

This Symptom Index is recommended as the symptom scoring instrument to be used in the:

·        initial assessment of each patient presenting with symptoms of prostatism

·        primary determinant of treatment response

·        assessment of disease progression in the follow up period.

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Options for treatment 

EHB 1995 summary

Benign Prostatic Hypertrophy. Effective Health Care December 1995 Vol. 2.NHS Centre for Reviews and Dissemination. University of York.

·        Enlargement of the prostate affects about one third of men over 50 and can cause distressing urinary symptoms.

·        The progress of benign prostatic hyperplasia (BPH) is unpredictable, but only a minority of men deteriorate rapidly and some will improve spontaneously.

·        Many men willingly tolerate mild symptoms of BPH. Care should be taken not to overtreat men who are not too bothered by their symptoms.

·        For the majority of men whose symptoms are not unacceptably severe, the condition may be best managed by watchful waiting and simple lifestyle changes e.g. decrease intake of caffeine, bladder training

·        The most effective treatment for severe symptoms is surgery, but about a quarter of men fail to benefit and some end up worse.

·        The most common operation for BPH is transurethral resection of the prostate (TURP). Incision of the prostate (TUIP) is often just as effective, uses fewer resources and is less hazardous; however it is under-used.

·        Drug therapy on average has a small effect on symptoms, but some men may experience significant benefit.

·        Because each type of treatment involves a different balance of risks and benefits, patients should be encouraged to participate in making decisions about their management.

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 Finasteride in BPH

An editorial in the BMJ by Kirby

Kirby R. Benign prostatic hyperplasia. BMJ 1999; 318:343-344.

 identified that the traditional goals of the management of BPH are:

·        Symptomatic relief

·        Improved flow rates

However a man in his 70s has a 1 in 10 chance of experiencing acute urinary retention within 5 years. Other risk factors for acute retention include:

·        Lower urinary tract symptoms

·        Depressed flow rate

·        Enlarged prostate gland e.g. > 40g

Acute retention of urine is associated with increased mortality and complications following surgery when compared with elective prostatic surgery.

Kirby reviews a RCT of finasteride versus placebo in the management of men with moderate to severe symptoms and an enlarged prostate. The trial lasted 4 years. Finasteride was associated with:

·        Increased flow rate

·        Reduced symptoms

·        Decreased surgical intervention

·        Decreased incidence of acute retention

The NNT to prevent one patient developing acute retention or surgical intervention was 15 patients treated for 4 years. But in addition patients would have the short term benefits of reduced symptoms.

It is suggested that finasteride be used in patients with large prostates. In primary care it is no reasonable to send all patients for U/S scanning and DRE is the most common assessment. Unfortunately DRE underestimates the size of prostates when compared with ultrasound. Kirby suggests a pragmatic approach that if the “prostate feels big….it is big!” and should be treated as such.

FM 2000.

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