Prostate and colon cancer share some risk factors, but they’re distinct conditions. They affect different organs and have different symptoms. The screening process and guidelines for both also differ.

Prostate cancer happens when cancerous cells grow in your prostate gland. This gland is connected to the urethra in people assigned male at birth, and it stores and carries sperm during ejaculation.

Colon cancer happens when cancerous cells grow in your large intestine. Your colon is part of your gastrointestinal (GI) tract. Your GI tract does not include your prostate.

Prostate and colon cancer are two of the most common types of cancer in the United States. Read on to learn how common each type is, what early signs and symptoms to watch out for, and how doctors diagnose and treat them.

According to the National Cancer Institute, prostate cancer is the second most commonly diagnosed form of cancer in the United States. Yet death from prostate cancer isn’t as common as it is with several other cancers.

Colorectal cancer, which includes colon cancer, is the fourth most commonly diagnosed form of cancer. But it’s the second most common cause of death from cancer.

The American Cancer Society (ACS) estimates there will be about 288,300 new prostate cancer diagnoses in 2023, compared with 106,970 new colon cancer diagnoses. Still, the ACS predicts that colorectal cancer will be responsible for about 18,000 more deaths than prostate cancer.

Plus, a 2020 research review found that cancer screening was much less common for African Americans, Asian Americans, Latinx Americans, and American Indians. This means that actual rates of prostate and colon cancer may be inaccurate due to the lack of access to adequate medical resources in many of these communities.

Age is a risk factor for both prostate and colon cancer. The average age of diagnosis for prostate cancer is 66 years, while it ranges from 68–72 years for colon cancer. However, rates of colorectal cancer among adults ages 50 and younger have been increasing in recent years, according to 2019 research.

A family history of either condition also increases your risk of that cancer.

A personal history of GI disorders like inflammatory bowel disease can also increase your risk of colon cancer.

Data from the Office of Minority Health suggests that the risk of both prostate and colorectal cancer is higher in Black people in the United States. This stems partly from disparities in healthcare for Black people, such as limited access to care and a lower quality of care.

The early signs and symptoms of prostate and colon cancer usually differ by location in the body. People with prostate cancer often don’t experience any symptoms until later stages.

The most widely recognized symptoms of prostate cancer are changes in your urinary habits and function. Other symptoms include:

Colon cancer causes changes in your bowel habits and can cause pain in your abdomen. Other symptoms of colon cancer include:

The ACS recommends you undergo screening for prostate cancer starting at age 50, with recommendations for earlier screenings if you’re Black or have a close relative with prostate cancer.

Screening tests for prostate cancer include:

The U.S. Preventive Services Task Force recommends starting colon cancer screening at age 45. If you have a family history or other risk factors, talk with your healthcare team about what age you should start receiving screening to help ensure cancer is caught early.

Screening tests for colon cancer include:

  • fecal testing to look for blood or other substances in your blood that can indicate colon cancer
  • liver function tests or blood tests to rule out other conditions that can cause similar symptoms
  • sigmoidoscopy or colonoscopy to look inside your colon for cancer and remove tissue for biopsy
  • X-rays and CT scans to get detailed images of your colon and the surrounding areas

Can a colonoscopy detect prostate cancer?

A colonoscopy can’t detect prostate cancer. A colonoscopy can show only the inside of your colon, and the prostate is located near your bladder outside of your GI tract.

However, doctors typically perform a digital rectal exam before a colonoscopy. This provides an opportunity to screen for prostate cancer.

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Prostate cancer tends to grow more slowly than colon cancer, so treatment may be less invasive and mainly consist of active surveillance to ensure it doesn’t grow to an unmanageable level.

If cancerous cells have taken over your prostate, you may need a simple or radical prostatectomy to remove your prostate gland. If the cancer spreads further, you may also need:

Colon cancer often grows quickly and can spread beyond your colon. Colon cancer also tends to disrupt your body’s ability to digest food and pass waste, which can be dangerous to your overall health.

Active surveillance may be necessary at the earliest stages of colon cancer. As cancerous cells spread, some treatment options for colon cancer might include:

Even after successful treatment, some people with prostate or colon cancer can develop a second, unrelated cancer.

A 2017 Korean study found that the risk of prostate cancer in people over age 55 was higher if they previously had colorectal cancer.

Similarly, a 2016 Canadian study found that the risk of colon cancer may be higher in people who previously underwent radiation for prostate cancer.

However, the ACS notes that the following second cancers are more common for prostate cancer and for colon cancer:

Second cancers from prostate cancerSecond cancers from colon cancer
small intestine
bile duct
• small intestine
mouth or throat

Prostate cancer affects the prostate gland in people assigned male at birth. Colon cancer affects your large intestine, which helps you digest food and remove waste.

The symptoms, diagnostic tests, and treatments for each type of cancer are different and require different specialists. Talk with a doctor if you’re concerned about early signs of these cancers.