Prostate screening and disease

If I have an  abnormal clinical finding, does that make me a patient?

MINDSET:   HOW DO I THINK ABOUT HEALTH AND DISEASE?

Many  (especially older)  people are regularly reminded  by their doctor that it is time for an annual check-up.  They usually feel  reasonably well, but modern medicine,  with its preoccupation with figures and statistics, does not usually allow this euphoria.

Usually they will be told that they have hypertension or diabetes or high cholesterol  or even that they are obese or exercise too little or have unhealthy eating habits or that they drink too much. In the British National Health System general practitioners are rewarded according to “The Quality and outcomes” framework (QoF) where good performance earns awards points on the system, with related payments for each documentation. Many patients are sent for more tests and eventually most are started on pills. Few are considered not at risk for something.

Thus, of those who thought themselves as healthy, a number will return home as patients  and even be worried by the perception that they are now regarded to be ill.  What kind of medical system  is this:  turning people into patients?

It seems that many governments see 75year olds as patients. It is a trend with many causes, including overenthusiastic and uncritical interpretation of various guidelines, the payment structure of the NHS obsession with government targets superceding common sense, insurance companies and relentless pressure from drug industry.

Many busy family doctors do not understand the difference between relative and absolute risk. If an advantage has been shown of one treatment over the other of say 30%,  but you had to enroll 100,000 patients to get nine patients to improve versus six in the no treatment group, the absolute risk is negligible and the treatment should not be implemented.

I would like to use prostate examination for detection of cancer as an example.  There are two risks to screening for prostate cancer. It depends on your view where you would see the greatest risk  –  it can be in either:

1)       Not to screen, and miss a cancer

2)      Overdiagnosis and overtreatment, with dire consequences.

The following discussion becomes quite technical and younger readers might find it heavy going (feel free to skip this), but the adult men I see in my practice always have questions about possible prostate pathology.

“Overdiagnosis”  refers to the detection,  by screening,  of conditions that would not have become clinically significant (you cannot prevent something that would not have happened anyway).  It may thus happen, by screening, that cancer, that would never have become clinically significant, is found.  Patients are subject to the risks of screening, confirmatory diagnosis, and treatment, as well as suffering potential psychosocial harm from anxiety and labeling. “Overdiagnosis”  is of particular concern because most men with screening-detected prostate cancers have early-stage disease and will be offered aggressive treatment with potential long term consequences.

A number of reports have raised concerns about the risk of overdiagnosis through screening: While the lifetime risk of being  DIAGNOSED  with prostate cancer is now 1 in 6, the lifetime risk of DYING  from prostate cancer is only 1 in 34 [1] . Although about 80 percent of detected cancers are considered clinically important based on tumor size and grade [129] , these are relatively crude prognostic markers. An autopsy series in men who died from other causes have shown a 30 to 45 percent prevalence of prostate cancer in men in their fifties and an 80 percent prevalence in men in their seventies [130-132].  (This means that almost all men will in the long run develop prostate cancer if they live long enough).

A study that applied computer-simulation models of PSA testing to cancer incidence data estimated that 29 %  of cancers detected in whites and 44 % of cancers detected in blacks were overdiagnosed [133] . Similarly, a study that applied simulation models to the results of the European Randomized Study of Screening for Prostate Cancer estimated a 50 % overdetection rate with annual screening for men aged 55 to 67 [13] .

What are the risks of  therapy?

Even in the absence of treatment, many men diagnosed with prostate cancer as a result of screening will have a lengthy period of time without clinical problems. However, undergoing radical prostatectomy and radiation therapies can lead to immediate complications: The operative mortality rate is about 0.5 %  [134] (1 %  in men over 75 years of age)  [135] . Less serious, but more common, complications include urinary incontinence, sexual dysfunction, and bowel problems. Radical prostatectomy can substantially decrease sexual function in 20 – 70 % of men and lead to urinary problems in 15 – 50 %  [136,137] .

External beam radiation therapy has been reported to cause erectile dysfunction in 20 – 45 %  of men with previously normal erectile function, urinary incontinence in 2 – 16 % of previously

continent men, and bowel dysfunction in 6 – 25 %  of men with previously normal bowel function [136,138] .

Given the lack of data on whether screening improves disease-free survival, the quality of life issues related to treatment selection become increasingly important decision-making factors.

The American College of Physicians provided a useful summary of discussion points to consider when counseling patients about prostate cancer screening [140] :

Prostate cancer is an important health problem.

The benefits of one-time or repeated screening and aggressive treatment of prostate cancer have not yet been proven.

Digital rectal examinations and PSA measurements can have both false-positive and false-negative results.

The probability that further invasive evaluation will be required as a result of testing is relatively high.

Aggressive therapy is necessary to realize any benefit from the discovery of a tumor.

A small but finite risk for early death and a significant risk for chronic illness, particularly with regard to sexual and urinary function, are associated with these treatments.

Early detection may save lives.

Early detection and treatment may avert future cancer-related illness.

A healthy lifestyle does play a role:  low fat diet, exercise, no smoking, avoid chemical carcinogens is always protective in a large number of diseases.

Physicians find it challenging to provide comprehensive, consistent, and balanced information about prostate cancer screening decisions during clinic visits [144] . Consequently, efforts have focused on using decision aids to help patients understand screening issues and make informed decisions for screening [145] .

Investigators have evaluated a number of interventions to facilitate such informed prostate cancer screening decisions including videotapes [146-148] , patient group discussions [146] , brief scripts read to patients during clinic visits [149] , verbal and written material provided before a periodic health examination [150] , and informational pamphlets distributed at study visits [151] or through the mail [152] .

Before full information 98% of men reported for  PSA screening,  but with complete information only 50% of men reported for screening.

This means the (informed) choice is yours.  Your decision will depend on what is important in your life.  Family history of early cancer?  How important is your virility to you? Fear of illness or death?

RECOMMENDATIONS FOR SCREENING BY EXPERT GROUPS — In the face of the lack of outcomes data from randomized, controlled trials, major medical associations and societies have not come to a clear consensus regarding recommendations for screening for prostate cancer.

1.The United States Preventive Services Task Force (USPSTF) concluded that there is insufficient evidence to assess the balance of benefits and harms of prostate cancer screening in men younger than age 75 . The USPSTF recommends against screening for prostate cancer in men ages 75 or older because the harms of screening outweigh the benefits.

2. The Canadian Task Force on Preventive Health Care recommends against screening for prostate cancer with PSA and states that there is insufficient evidence to recommend for or against screening with DRE (digital rectal examination)] .

3.A number of European groups, including the European Union,  recommend against screening for prostate cancer while awaiting the results of randomized trials .

4.The American Cancer Society (ACS) emphasizes the need for physicians to provide men with adequate information regarding the risks and benefits of screening  . The ACS recommends that serum PSA testing and DRE should be offered annually to men 50 years of age and older who have a life expectancy of 10 years. The guidelines also stress the benefit of screening beginning at age 45 in patients at high risk of developing prostate cancer (eg, black men and men with a first-degree relative with prostate cancer diagnosed at a younger age). PSA testing is recommended for men who ask their clinicians to make the decision about screening on their behalf. The American Urological Association (AUA) also supports this policy .

5. The American College of Physicians (ACP) recommendation states that “Rather than screening all men for prostate cancer as a matter of routine, physicians should describe the potential benefits and known harms of screening, diagnosis, and treatment; listen to the patient’s concerns; and then individualize the decision to screen” . The ACP also suggests that men between the ages of 50 to 69 years are most likely to benefit from screening. Black men and men with a positive family history of prostate cancer should be informed of their higher lifetime risk, although the available evidence does not suggest that they need to be treated differently from men at average risk.

Two new studies into prostate-specific  antigen (PSA) screening for prostate cancer published in the NEJM have raised more questions than they answered.

1. One study found that the test had virtually no impact on prostate cancer and only lead to high risk of overdiagnosis and overtreatment.
2. The other study, on the other hand,  showed a small reduction in mortality risk after a nine year follow-up  in men who were screened regularly with PSA.  The study published in NEJM 18 March from American Cancer Institute and European Erasmus Centre looked at 182,000 men in Europe and 77,000 men in the US.  According to the US investigators mortality was actually somewhat higher in the screened group..

Daar is nog twyfel oor die vraag of ons sekere pasiente kan vrywaar daarteen om prostaatkanker te ontwikkel.  Deur jaarliks vir prostaat ondersoeke te gaan glo ons dat dit bydra tot gesonde lewenstyl. Baie van ons gaan getrou elke jaar vir hierdie ondersoek (waaraan  baie min mans hulleself  vrywillig aan sal onderwerp.

Om nou te hoor dat ons nog steeds nie die sekerheid van wetenskaplike bewyse het dat  die ondersoek wel  lewens  spaar en ons nie net teen prostaatkanker beskerm nie maar ook lewens  sal red,  onstel baie van ons.   Wat is die feite,  moet ons maar die ongemak een maal per jaar verdra, of is dit nie bewys om lewens te red nie?

Om hierdie vraag te probeer antwoord het  navorsers by een van die beste kanker- eenhede in die wêreld,  nl. die “Division of Cancer Prevention, National Cancer Institute” in Bethesda in dieVSA, ‘n navorsingsmodel opgestel.  Tussen 1993-2001 het hulle op lukraak wyse 76,693 mans in twee groepe verdeel.

1. Een groep van 38,350 mans kry ‘n jaarlikse rektale ondersoek en ‘n PSA- bloedtoets, volgens ‘n streng protokol.  Die PSA word vir 6 jaar opgevolg en die rektale ondersoek vir 4 jaar.
2. Die ander 38,350 mans kry gewone ondersoeke,  wat beteken nie noodwendig rektale en PSA-ondersoeke nie,  maar soms wel indien die dokter dit nodig sou ag.

Resultaat:  In die toetsgroep word 85% ondersoek en die kontrole groep word 52% ondersoek. Na 7 jaar waarin die groepe opgevolg word is die insidensie van prostaat kanker per  10,000 persoon jare 116 (2820 ware gevalle) in die proefgroep, en in die kontrole groep 95 (2322). Die sterfgevalle in die toets groep was 2 (50)per 10,000 persoon jare en 1.7 (44 )per 10,000 persoon jare. Dit het dus ‘n baie lae insidensie van sterfte getoon in albei groepe. Daar was geen verskil in die voorkoms van kanker of hulle ondersoek is of nie.

Uiteindelike vraag:  Is dit vir my die regte ding is om ondersoek te word?.  Waar lê die keuse tussen

• oordiagnose en onnodige radikale behandeling;
• of die kans dat ons ‘n kanker wat my kan doodmaak,  mis en die vroeё kans om genees te word misloop.