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Prostate Cancer

Observation or Active Surveillance for Prostate Cancer

Not all prostate cancers are the same. Some can grow quickly, but others tend to grow very slowly. Some men with slow-growing prostate cancers (especially men who are older or have other serious health problems) might never need treatment. Instead, their doctors may recommend active surveillance or observation (sometimes called watchful waiting).

What are active surveillance and observation?

The terms active surveillance and observation mean something slightly different.

Active surveillance is often used to mean monitoring the cancer closely, with a plan to treat it if tests show it’s starting to grow more quickly. Usually this approach includes doctor visits with a prostate-specific antigen (PSA) blood test about every 6 months and a digital rectal exam (DRE) about once a year. Prostate biopsies and imaging tests may be done every 1 to 3 years as well. Exactly how often tests are done can be tailored to some extent, based on each man’s situation and preferences.

If your test results change, your doctor would then talk to you about treatment options to try to cure the cancer.

Observation (watchful waiting) is sometimes used to describe a less intense type of follow-up that includes fewer tests and that relies more on changes in a man’s symptoms to decide if treatment is needed. This is more likely to be a good option for men who are older and/or have other serious health problems.

No matter which term your doctor uses, it’s very important for you to understand exactly what they mean when they refer to it.

When are these options used?

One of these approaches might be recommended (or at least be an option) if your cancer:

These approaches are not likely to be good options if you have a fast-growing cancer or if the cancer is likely to spread outside the prostate.

The main advantage of active surveillance and observation is that these approaches allow some men with slow-growing cancers to avoid (or at least delay) treatments, such as surgery or radiation, which can often have bothersome side effects. Many of these men will never need treatment for their cancer. If they do eventually need treatment, it’s unlikely that the wait will have had an effect on how long they live.  

These approaches can have some potential downsides as well. For example, in a small percentage of cases, even a cancer that is thought to be slow growing might start growing faster or spread outside the prostate. This might be because the prostate biopsy missed a faster-growing part of the cancer, or because the cancer changed over time and became more aggressive. In either case, this might make it harder to cure the cancer than if it were treated when it was first found.

These approaches also require lifelong doctor visits and tests to monitor the cancer, especially with active surveillance. These visits and tests can be time-consuming, and waiting for test results might lead to anxiety for some men.

Finally, some men might just not be comfortable knowing they have “cancer” in their body, even if it’s never likely to cause them any problems. This concern might lead some men to choose treatment, such as surgery or radiation therapy, even if the treatment is unlikely to help them live longer (and is still likely to cause side effects).

Comparing active surveillance and treatment

Some men might want to know if studies have been done to compare active surveillance with immediate treatment with surgery or radiation therapy. Unfortunately, we don’t have results from large studies directly comparing active surveillance with treatment in men with slow-growing prostate cancer.

Some studies have compared slightly different groups. For example, studies have compared observation (with less intense follow-up than active surveillance) versus treatment. Some studies that have looked at this issue also included men who would now be considered at higher risk (and therefore likely wouldn’t be offered active surveillance today).

In the studies that have been done so far, it doesn’t appear that men who are treated right away are likely to live any longer than men who choose active surveillance.

Finally, it’s important to keep in mind that while there are still some questions about active surveillance, the tools doctors use to decide which men might benefit from it have improved a great deal in recent years. This includes the development of risk groups and molecular tests, as well as imaging tests, such as multiparametric MRI (mpMRI), all of which can help tell which men are most likely to be good candidates for active surveillance.

Doctors also continue to refine the best ways to monitor men who are on active surveillance, so they get the necessary tests to look for cancer progression while not being tested too often.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

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Last Revised: November 22, 2023

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