Prostate cancer is the second leading cause of cancer among adult males in the United States, after skin cancer. However, it is highly treatable, especially in the early stages.
Prostate cancer starts in the prostate gland, which is part of the male reproductive system. The gland produces a fluid that, together with sperm from the testicles, makes up semen. Muscle cells inside the prostate play a role in ejaculation.
The American Cancer Society (ACS) expect that there will be 174,650 new prostate cancer diagnoses in the U.S. in 2019 and that around 31,620 people in the country will die from this type of cancer during the year.
The ACS also note that 1 in 9 men will receive a diagnosis of prostate cancer during their lifetimes, and around 1 in 41 men will die from the disease. With treatment, there is a good chance of surviving prostate cancer.
Prostate cancer often produces no symptoms in the early stages. After a certain age, the doctor may recommend regular screening. A prostate exam can help detect cancer while it is still highly treatable, even if symptoms are not present.
Screening involves looking for early signs of a disease in people who do not have any symptoms. Cancer screening aims to detect telltale changes at an early stage, when treatment is more likely to be effective.
Doctors commonly use two main tests to screen for prostate cancer:
- the digital rectal exam (DRE)
- the prostate-specific antigen (PSA) test
Neither test can confirm that prostate cancer is present, as various other factors may influence results. However, these tests can indicate whether further steps are necessary.
A prostate biopsy is the only way to confirm that a person has prostate cancer.
Before undergoing either of these tests, the person will need to give consent, which involves confirming that they understand the potential benefits and risks.
The DRE is a physical examination for changes in the prostate that could indicate a tumor.
Before the DRE
Common questions to ask before a DRE include:
- What will happen during the DRE?
- How long will it take?
- Will it be painful?
- How accurate is a DRE, in terms of finding cancer?
- What will happen next?
The individual should also:
Inform their healthcare team if they have hemorrhoids or anal fissures, as a DRE may exacerbate these.
Ask their insurance provider about coverage and whether there will be additional costs.
During the DRE
The procedure usually requires the person to undress from the waist down.
The specialist may instruct the person to lie on their left side and pull their knees up to their chest or to stand and lean against a table.
The specialist will:
- put on some gloves and put lubricant on one finger
- assess the area around the rectum for anything unusual
- gently insert a lubricated, gloved finger into the rectum
- feel the prostate to assess the size and check for bumps, soft or hard spots, and other abnormalities
A DRE is not usually painful, but it may be slightly uncomfortable. It takes only a few minutes to complete.
After the DRE
After the exam, the doctor will explain the results.
The person can usually go back to their regular activities immediately after a DRE.
However, there may be some bleeding from the rectum afterward, particularly if the person has hemorrhoids or anal fissures. If bleeding persists or is significant, the person should contact their healthcare provider.
The doctor will usually explain the results of the DRE after the exam.
The person may also undergo a PSA test on the same day. If the doctor believes that further steps may be necessary, they will base this on the results of both the PSA and DRE.
It is worth noting that a DRE often produces a false-positive result. If the doctor detects changes in the prostate gland, this does not necessarily indicate cancer.
Prostate nodules can develop because of prostate cancer or other prostate-related conditions. Learn more about prostate nodules here.
This blood test measures the amount of PSA that the prostate gland produces. Some of this antigen leaks into the blood and will show up during testing.
High levels of PSA in the blood can indicate prostate cancer, but various other conditions and factors can raise PSA levels. High levels do not necessarily mean that cancer is present.
What does the PSA test involve?
The PSA test involves taking a blood sample and sending it to a laboratory for analysis. The results indicate:
Normal levels: Most healthy adult males have PSA levels below 4 nanograms per milliliter (ng/ml).
Borderline levels: PSA levels of 4–10 ng/ml are borderline. There is a 1 in 4 chance that cancer is present.
High levels: If PSA levels are over 10 ng/ml, there is a 50% chance that the person has prostate cancer. The specialist will likely recommend more testing, including a prostate biopsy.
It is important to note that PSA levels can naturally vary from person to person. A person with high levels may not have prostate cancer. On the other hand, about 15% of people who test positive for prostate cancer after a biopsy have PSA levels below 4 ng/ml.
Prostate cancer is not the only cause of high PSA levels. Find out more about the other causes here.
What do the results mean?
PSA levels may be above the baseline for various reasons other than prostate cancer.
Other factors that can raise PSA levels include:
- older age
- recent ejaculation
- medical procedures, including a DRE, a biopsy, or some urological investigations
- testosterone supplementation
- an enlarged prostate — because of benign prostatic hyperplasia (BPH), for example
- prostatitis, which is inflammation and swelling of the prostate
Also, people with obesity may have lower PSA readings.
In addition, some medications may reduce PSA levels, including:
- 5-alpha reductase inhibitors, which can help treat BPH
- aspirin, which some people take regularly as a blood thinner
- statins, which help manage cholesterol levels
- thiazide diuretics, a kind of water pill that can help reduce high blood pressure
Some herbal medicines and supplements can also lower PSA levels. Tell the doctor about any medications and supplements before undergoing the test.
High PSA levels alone do not indicate cancer. However, if a DRE also reveals changes, a doctor may recommend a biopsy for a more accurate result.
The PCA3 is another test for prostate cancer that doctors use in some circumstances. Find out more.
What happens next?
If the DRE and PSA tests show nothing unusual, the healthcare provider may recommend monitoring by repeating one or both tests every 1–2 years.
If the results could indicate prostate cancer, the doctor may recommend a biopsy.
A prostate biopsy can lead to complications. What are the alternatives?
There are no official guidelines about screening for prostate cancer, but the ACS recommend talking to a doctor about screening from the following ages:
- 50 years for males with an average risk and a life expectancy of more than 10 years
- 45 years for those with a high risk
- 40 years for people with more than one close relative who developed prostate cancer at an early age
People who have a high risk include African Americans, people with obesity, and anyone with a close relative who received a diagnosis of prostate cancer before age 65.
Not everyone recommends routine screening, however.
In 2018, the U.S. Preventive Services Task Force recommended that the decision to undergo screening from the ages of 55–69 years should be up to the individual. This is because screening can produce false positive results, leading to investigations or surgery that may not be necessary.
Before going ahead with screening, a person should discuss the risks and benefits with their doctor.
Does frequent ejaculation lower the risk of prostate cancer? Find out here.
Prostate cancer is common. However, if a doctor diagnoses the cancer while it remains in the prostate or nearby and the person receives treatment, it is almost 100% likely that they will survive for at least another 5 years.
If the cancer spreads to other parts of the body, this survival rate falls to 30%.
A person should start asking about the benefits of screening from age 50, or earlier, if they have a higher risk of prostate cancer.
If so many factors can influence DRE and PSA test results, how does the doctor decide whether to recommend a biopsy?
The doctor and the individual should make the decision about a biopsy together, based on the DRE and PSA results.
Doctors have historically used a PSA level of 4.0 ng/ml or higher to recommend referral for further evaluation or a biopsy.
When PSA levels are in the range of 2.5–4.0 ng/ml, healthcare providers should consider other factors that increase the risk of prostate cancer. These include being African American, having a family history of prostate cancer, increasing age, abnormal DRE, and high age‐specific PSA level. A person who has previously had a negative biopsy will have a lower risk.
Doctor’s commonly use risk calculators to estimate a percent risk of prostate cancer based on individual risk factors. Many use the Prostate Cancer Prevention Trial Prostate Cancer Risk Calculator. This was first available in 2006 and was updated in 2012. It is a good tool to aid in the decision of whether or not to perform a biopsy.Kevin Martinez, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.