Can Prostate Cancer Be Found Early?

Screening is testing to find cancer in people before they have symptoms. For some types of cancer, screening can help find cancers at an early stage, when they are likely to be easier to treat.

Screening options for prostate cancer

Prostate cancer can often be found early by testing for prostate-specific antigen (PSA) levels in a man’s blood. Another way to find prostate cancer is the digital rectal exam (DRE). For a DRE, the doctor puts a gloved, lubricated finger into the rectum to feel the prostate gland. These tests and the actual process of screening are described in more detail in Screening Tests for Prostate Cancer.

If the results of either of these tests is abnormal, further testing (such as a prostate biopsy) is often done to see if a man has cancer.

Pros and cons of prostate cancer screening

Finding prostate cancer early

The main benefit of screening is that if prostate cancer is found as a result, it’s likely to be at an earlier stage than if no screening were done. This will most likely mean that the cancer is easier to treat.

While this might make it seem like prostate cancer screening would always be a good thing, there are issues around screening that make it unclear if the benefits outweigh the risks for most men.

Possible inaccurate or unclear test results

The PSA blood test can sometimes have abnormal results even when a man does not have cancer (known as a false-positive result), or normal results even when a man does have cancer (known as a false-negative result).

False-positive results can lead some men to get prostate biopsies (with small risks of pain, infection, and bleeding) when they don’t have cancer. These results can also lead to anxiety, even when a biopsy doesn’t find cancer.

On the other hand, false-negative results can give some men a false sense of security, even though they might actually have prostate cancer.

Researchers are studying ways to make the PSA test more accurate (see Screening Tests for Prostate Cancer), as well as trying to develop other, more accurate screening tests. But for now, the possibility of false-positive and false-negative results from a PSA test needs to be considered when deciding whether to be screened for prostate cancer.

Overdiagnosis and overtreatment

Another important issue is that not all prostate cancers are the same. Some might grow quickly, but others most likely would never cause serious health issues. Even if screening detects prostate cancer, doctors sometimes can’t tell if the cancer is truly dangerous (and therefore needs to be treated). Finding and treating all prostate cancers early might seem to make sense, but some prostate cancers grow so slowly that they would never cause any problems during a man’s lifetime.

Because of screening, some men may be diagnosed with a prostate cancer that they never would have known about otherwise. It would never have led to their death, or even caused any symptoms. Finding a “disease” like this that would never cause problems is known as overdiagnosis.

A problem with overdiagnosis in prostate cancer is that many of these men might still be treated with surgery or radiation, either because the doctor can’t be sure how quickly the cancer might grow and spread, or because the man is uncomfortable knowing he has cancer that isn’t being treated. Treatment of a cancer that would never have caused any problems is known as overtreatment. The major downside of this is that even if a treatment like surgery or radiation wasn’t needed, it can still cause urinary, bowel, and/or sexual side effects that can seriously affect a man’s quality of life.

If early prostate cancer is found, men and their health care providers may end up struggling to decide if treatment is needed or if the cancer can just be closely watched without being treated right away (an approach called watchful waiting or active surveillance). Even when men aren’t treated right away, they still need regular blood PSA tests and prostate biopsies to determine their need for treatment in the future. These tests can lead to anxiety, as well as risks of pain, infection, and bleeding.

It’s not clear from studies if benefits of screening outweigh the risks

Doctors are still studying if screening will lower the risk of death from prostate cancer. The results from 2 large studies have been conflicting, and they have not offered clear answers.

• Results from a large study done in the United States found that annual screening with PSA and DRE did detect more prostate cancers than in men not screened, but this screening did not lower the death rate from prostate cancer. However, questions have been raised about this study, because some men in the non-screening group actually were screened during the study, which might have affected the results.
• A large European study did find a lower risk of death from prostate cancer with PSA screening (done about once every 4 years), but the researchers estimated that about 570 men would need to be invited to be screened (and 18 cancers would need to be detected) to prevent one death from prostate cancer.
• So far, neither of these studies has shown that PSA screening helps men live longer overall (that is, that it lowers the overall death rate).

Both of these studies are being continued to see if longer follow-up will give clearer results. Prostate cancer screening is being explored in several other large studies as well.

For now, the American Cancer Society recommends that men thinking about getting screened for prostate cancer learn as much as they can so they can make an informed decision based on available information, discussions with their health care provider, and their own views on the possible benefits, risks, and limits of screening. (To learn more, see American Cancer Society Recommendations for Prostate Cancer Early Detection.)

Until more information is available, you and your health care provider should decide whether you should be screened for prostate cancer. There are many factors to take into account, including your age, health, and family history. For example, you might feel it’s more important to be screened if prostate cancer runs in your family.

If you’re younger and develop prostate cancer, it may shorten your life if it’s not caught early. Screening men who are much older or in poor health is less likely to be helpful. This is because most prostate cancers are slow-growing, and men who are older or have major health problems are often more likely to die from other causes before their prostate cancer grows enough to cause problems.