Prostate cancer screening

From Wikipedia, the free encyclopedia

Prostate cancer screening is an attempt to identify individuals with prostate cancer in a broad segment of the population—those for whom there is no reason to suspect prostate cancer. There are currently^[update] two methods used: One is the digital rectal examination (DRE), in which the examiner inserts a gloved, lubricated finger into the rectum to examine the adjoining prostate. The other is the prostate-specific antigen (PSA) blood test, which measures the concentration of this molecule in the blood.

The decision to screen has many controversies, such as screening older men for whom benefit is least clear.^[1] Doctors in some countries are reluctant to screen younger patients because screening tends to put a large number of healthy men through potentially harmful medical procedures just to detect a single tumour in one of them.

Contents 1 Interpreting the results of screening tests 2 Randomized controlled trials 3 Clinical practice guidelines 4 External links 5 References

[edit] Interpreting the results of screening tests

Two clinical prediction rules help predict the probability of cancer based on the level of the prostate-specific antigen and other clinical findings.^[2][3]

[edit] Randomized controlled trials

The results from two of the largest randomized trials have now been published. ^[4]

In the European Randomized Study of Screening for Prostate Cancer initiated in the early 1990s the intention was to evaluate the effect of screening with prostate-specific antigen (PSA) testing on death rates from prostate cancer. The trial involved 182,000 men between the ages of 50 and 74 years in seven European countries randomly assigned to a group that was offered PSA screening at an average of once every 4 years or to a control group that did not receive such screening. During a median follow-up of almost 9 years, the cumulative detected incidence of prostate cancer was 820 per 10,000 in the screening group and 480 per 10,000 in the control group. Deaths from these cancers in this time was much lower. There were 214 prostate cancer deaths in the screening group and 326 in the control group, a difference of 71 men per 10,000 in the tested group compared to the control. The researchers concluded that PSA-based screening did reduce the rate of death from prostate cancer by 20% but that this was associated with a high risk of overdiagnosis. Statistically, it means that 1410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent just one death from prostate cancer. ^[5]

A US study looked at the general effectiveness of a screening program involving both PSA and DRE methods. This was conducted between 1993 thu 2001, in which 76,693 men at 10 U.S. study centers 38,343 subjects received screening (an annual PSA testing for 6 years and DRE for 4 years) and a control group of 38,350 subjects reveived 'usual care' with subjects and health care providers receiving the results and deciding on the type of follow-up evaluation. 'Usual care' means that some in this group would have received some screening, as some organizations have recommended. After 7 years of follow-up, the incidence of prostate cancer per 10,000 person-years was 116 (2,820 cancers) in the screening group and 95 (2,322 cancers) in the control group. The incidence of death attributed to prostate cancer per 10,000 person-years was 2.0 (50 deaths) in the screening group and 1.7 (44 deaths) in the control group (rate ratio, 1.13; 95% CI, 0.75 to 1.70). The data at 10 years were 67% complete and consistent with these overall findings. The researchers concluded that after 7 to 10 years of follow-up, the rate of death from prostate cancer was very low and did not differ significantly between the two study groups.^[6]

Commenting on the findings, the Chief Medical Officer of the American Cancer Society, Otis W. Brawley, MD, said

many experts had anticipated these studies would show a small number of men will benefit from prostate screening, but a large number of men will be treated unnecessarily. And that's what these studies show. However, the question is not as simple as: 'does prostate cancer screening work?' What we need to know is: what are benefits of prostate cancer screening and are they large enough to outweigh the harms associated with it? And despite the release of this early data, we still cannot say whether the benefits outweigh the risk.^[7]"

His Deputy chief medical officer, Len Lichtenfeld, MD, MACP said

"When one considers all of the problems associated with treatment for prostate cancer -- urine incontinence, impotence, pain and bleeding among others -- that is a lot of men left with a lot of symptoms to save one life."

A further study, the NHS Comparison Arm for ProtecT (CAP) and Prostate testing for cancer and Treatment (ProtecT) studies randomized GP practices with 460,000 men aged 50–69 at centers in 9 cities in Britain from 2001-2005 to usual care or prostate cancer screening with PSA (biopsy if PSA ≥ 3)^[8], has yet to report.

[edit] Clinical practice guidelines

Clinical practice guidelines for prostate cancer screening are controversial because the benefits of screening may not outweigh the risks of follow-up diagnostic tests and cancer treatments:

• U.S. Preventive Services Task Force (USPSTF):^{[9][10][11][12]}

"the evidence is insufficient to recommend for or against routine screening for prostate cancer using prostate-specific antigen (PSA) testing or digital rectal examination (DRE). This is a grade I recommendation". In 2008, the guidelines were updated to recommend against the routine screening of prostate cancer in men age 75 years or older (Grade D recommendation).

• American Cancer Society, in 2009, recommended that men should sit down with their physician and weigh the benefits and risks of the test

If you're at a high risk for prostate cancer, you should start having that conversation as early as age 45. Men at high risk include African-American men and men who have a first-degree relative (father, brother, or son) diagnosed with prostate cancer at an early age (younger than age 65). Men with several first-degree relatives diagnosed at an early age should begin the discussion at age 40.^[13]

Other racial and ethnic groups, such as Asian- and Hispanic-Americans have a lower risk of prostate cancer, and may not benefit from screening. Screening is likely not useful for men over age 70 or with other significant medical problems and a life expectancy of fewer than 10 years.

[edit] External links

• Prostate UK Help us stop prostate diseases ruining lives

[edit] References