Understanding Prostate Cancer Screening (A Statement from the American College of Preventive Medicine and Medem)

The prostate is a small male sex gland located between the bladder and the rectum. It makes a fluid that forms part of a man's semen. It is possible for cancer cells to begin to grow in the prostate gland, leading to prostate cancer.

Men with prostate cancer often don't know they have it. This is because men may live with prostate cancer for many years without developing any symptoms. Screening tests allow doctors to check for prostate cancer in men who have no symptoms.

You may have heard different opinions about whether you should be screened for prostate cancer. You may have questions about your chances of getting prostate cancer, the tests involved in prostate cancer screening, or how well the screening tests work. It is no wonder that you might be uncertain about the benefits of prostate cancer screening; even doctors do not agree about the need for screening, who should be screened, and how often.

This article will help you understand screening for prostate cancer and make sense of the recommendations offered by different medical societies. Your final decision regarding whether you should be screened for prostate cancer should be made with the help of your doctor.

Prostate cancer is very common. In fact, in the United States, prostate cancer is the most commonly diagnosed cancer other than skin cancer. One in every five men in this country will develop prostate cancer before his death.

Prostate cancer tends to develop slowly. Most men live with prostate cancer for a long time without any problems or symptoms, and many never experience any problems at all. Men who do have symptoms often find them troublesome, and the symptoms sometimes interfere with their daily lives. Symptoms of prostate cancer include blood in the semen or urine, pain during ejaculation, and difficulty urinating.

Because prostate cancer usually grows slowly, most men with prostate cancer die of causes unrelated to their prostate cancer. This does not mean that prostate cancer is a harmless disease. Prostate cancer can cause troublesome symptoms, and most importantly, in some men the cancer spreads to other areas of the body and leads to death.

Survival rates following treatment are higher when the cancer does not spread outside the prostate. When the cancer is only in the prostate, or only in the area around the prostate, almost all men survive. When the cancer has spread throughout the body, about a third of men live for more than five years.

Although it can't be predicted who will develop prostate cancer, there are several risk factors for the disease:

• You are more likely to develop prostate cancer if you have a family history of the disease
• You are more likely to develop prostate cancer if you are African-American
• You are more likely to develop prostate cancer as you become older

It is possible that a diet high in fat increases the risk of prostate cancer, as well as working with some types of chemicals. More research is needed to determine whether these are true risk factors.

Another disease that becomes more common as men age is benign prostatic hyperplasia (BPH). Some of the symptoms of BPH are similar to prostate cancer, but BPH is not caused by cancer. Rather, BPH is caused by the abnormal growth of benign (non-cancer) prostate cells. The prostate gland becomes enlarged, and it can push against the bladder and the urethra, causing problems with urination. No studies have shown a direct link between BPH and prostate cancer.

It is important to realize that urinary problems in older men are much more likely to be caused by BPH than by prostate cancer. If you are experiencing urinary problems, talk to your doctor.

There are two main types of screening tests for prostate cancer, the digital rectal exam and measurement of prostate-specific antigen in the blood. Often, both screening tests are used together.

Digital rectal exam (DRE): For this test, the doctor puts on gloves, lubricates one finger, and puts that finger into the man's rectum. Because the prostate is located near the rectum, the doctor is able to feel the prostate through the rectum wall and check for any unusually hard or lumpy areas.

If any unusual areas are found with the DRE, the doctor will recommend further testing to determine their cause.

Prostate-specific antigen (PSA): Prostate-specific antigen (PSA) is a protein made by cells in the prostate. Most of the PSA made in the prostate leaves the body in semen, but a small amount enters the bloodstream. For PSA screening, a blood test is taken to measure levels of PSA in the blood. An elevated level of PSA in the blood can mean that a man has prostate cancer.

BPH or an infection in the prostate can also raise PSA levels. Because of this, prostate cancer can't be diagnosed with the PSA test alone. Instead, PSA screening is used to determine if further testing is necessary.

If screening tests suggest that you might have prostate cancer, your doctor may recommend an ultrasound exam and/or a biopsy.

• During ultrasound, sound waves are used to create pictures of the prostate. Signs of cancer are sometimes visible in these images.
• During a biopsy, a small amount of prostate tissue is removed. The tissue is examined for the presence of any cancer cells.

Medical societies are professional organizations made up of physicians or other health care providers. One of the tasks of medical societies is to issue screening and treatment recommendations.

Medical society members who are experts in a certain area of medicine often work together to review studies and develop recommendations for tests or treatments. Reviewing medical studies is important in this process because studies provide doctors with evidence about how well a screening program or treatment works for large groups, rather than for individuals. Likewise, recommendations are usually meant to be general enough to apply to large groups of people – in some cases, to all people in the country. For instance, screening recommendations for prostate cancer might focus on all men in the country or on large groups of men who are at high risk (such as African-American men).

It may seem logical that medical societies would recommend that every man receive all the screening tests available for a given disease, but this is not the case. When deciding if screening tests should be recommended, the most important concern for societies is whether the screening test will help save lives. If there is not good evidence that screening for and finding prostate cancer helps men live longer, then medical societies are less likely to recommend screening.

Doctors at medical societies consider the screening tests available by asking questions such as: Can the test results be trusted? Will other tests be needed to verify the results? Are there health risks involved in the tests? Are the patients who are tested likely to be very worried about the test and its results?

Also, doctors at medical societies consider how well treatment for the disease works. When effective treatments for a disease are not available, medical societies are much less likely to recommend that people be screened for that disease.

Finally, there are financial costs involved when recommending screening tests for large numbers of people – costs for equipment, lab work and doctors' time. If a medical society believes that the benefits from screening outweigh the costs and risks to the patients, the society will recommend screening. On the other hand, if a medical society is not convinced that the benefits will outweigh the costs and risks, the society may not recommend screening.

Some of the main points considered by medical societies when developing prostate cancer screening recommendations are:

• Prostate cancer is common in the United States and can cause troublesome symptoms. If it spreads, prostate cancer can lead to death.
• Studies have shown that DRE and PSA tests can help detect prostate cancer.
• Finding prostate cancer at an early stage might allow men and their doctors to explore treatment options that prevent cancer spread and improve survival. However, more studies are needed to better understand whether screening for prostate cancer helps men remain healthy and live longer.
• Screening tests for prostate cancer are not very accurate. If an elevated PSA is found, additional testing must be done to determine whether cancer is actually present (called diagnostic testing). The need for these additional, diagnostic tests can be worrisome, and there are risks involved, even though the man may not have prostate cancer at all.
  • Needle biopsy is a common diagnostic test, and it carries a small risk of infections or bleeding.
• The results of screening and diagnostic tests for prostate cancer are not always correct.
  • Screening tests and biopsies for prostate cancer can give "false negative" results. This means that the test results will be negative for cancer when, in fact, the results should be positive. So, not every man with prostate cancer will have his cancer detected using available screening and diagnostic tests.
  • It is also possible for a PSA test to give a "false positive" result. This means that the test shows that a man may have prostate cancer, when he actually does not have it.
• Doctors usually do not know how quickly the cancer will grow in men with prostate cancer. Many men have slow-growing prostate cancer that is unlikely to cause any symptoms or spread within the their lifetime.
• It is unclear how effective treatment for prostate cancer is – more studies are needed about surgery, radiation and other forms of treatment. Many men who have prostate cancer that is slow growing and found early do not need any treatment at all. Especially for older men or those with additional medical problems, doctors may suggest "watchful waiting." Watchful waiting means that the patient and his doctor monitor the cancer but do not treat it.
• If a man and his doctor decide to treat prostate cancer, most treatments have risks and side effects. The doctor will not know if the treatment will actually cure the prostate cancer. However, if a man does have a fast-growing prostate cancer, treatment may save his life.
  • Common treatments for prostate cancer are radical prostatectomy – or surgery to remove the prostate – and radiation therapy. These treatments can cause complications such as: urinary incontinence (the inability to control the urine flow), erectile dysfunction (the inability to have an erection needed for sexual intercourse) or strictures (narrowing of the urethra) and, rarely, can be fatal. Most doctors think that men who will probably live less than 10 years after the surgery should not have a radical prostatectomy.

Several medical societies have published recommendations for prostate cancer screening. It might surprise or worry you to know that they do not all recommend exactly the same screening practices.

Although it is often true that recommendations for medical societies differ from one another, this does not mean that one society is correct and the others are wrong. In the case of prostate cancer, we have seen that it is unclear whether the benefits of screening and treatment for prostate cancer outweigh the risks and costs involved. Medical societies consider the evidence available from studies and create their best recommendations.

• The American College of Preventive Medicine recommends against routine population screening with DRE and PSA. They recommend that men age 50 or older, who are expected to live at least 10 years, be given information about the potential benefits and harms of screening, and the limits of current evidence. They recommend that doctors help men make their own choices about screening, based on personal preferences.
• The American Cancer Society and the American Urological Association recommend that health care providers offer PSA and DRE testing yearly, beginning at age 50 years, to men who are expected to live for at least 10 years. Men at high risk, such as African-Americans and men who have a first-degree relative (father, brother, son) diagnosed with prostate cancer at an early age, should begin testing at a younger age (45 years). They recommend that men and their health care providers discuss the potential benefits, side effects, and questions about early prostate cancer detection and treatment, so that men can make informed decisions about testing.
• The American College of Physicians recommends that health care providers give men information about the benefits and harms of prostate cancer screening to help them make a decision based on personal preferences.
• The U.S. Preventive Services Task Force (a group appointed by the U.S. Federal Government) recommends against routine screening for prostate cancer (this recommendation is currently being revised).

While there are differences among the medical societies' recommendations, most societies agree that the decision to screen for prostate cancer is a personal choice that should be based on education, discussions between a man and his doctor, and a good understanding of the issues.

As more information about screening and treatments for prostate cancer becomes available, medical societies may change their recommendations. For instance, recent data show that the rate of death from prostate cancer is decreasing. This may mean that the use of prostate cancer screening, and improvements in care, are helping men with prostate cancer live longer lives. However, more studies are needed to truly understand the role of screening in improving survival with prostate cancer. Large studies are currently in progress in the United States and Europe to provide more evidence.

It is important to keep in mind that medical societies consider the male population as a whole – not individual patients – when they are making recommendations for prostate cancer screening. None of the medical societies recommend against any individual man being screened for prostate cancer. You and your doctor should consider your own risk factors, medical history and concerns to develop a plan for prostate cancer screening that is appropriate for you.

Copyright © 2001 MedemTM and American College of Preventive Medicine