Prostate and colon cancer are two of the most common types of cancer in the United States. While they share similarities, such as certain risk factors, they also have distinct differences, including where they occur and who they may affect. This influences how doctors diagnose and treat them.

Prostate and colon cancer are two common cancers that occur in the prostate and colon, respectively. Although they share some similarities, such as an increasing incidence with age, they are very different. Namely, they occur in different organs, and colon cancer can affect anyone, while prostate cancer only affects those born with a prostate. Additionally, colon cancer may present with bowel symptoms and prostate cancer with urinary symptoms.

This article will discuss some similarities and differences between prostate and colon cancer.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Prostate cancer describes cancer that occurs in the prostate gland. The prostate is a small organ about the size of a walnut, located between the bladder and the penis within the body. The prostate produces seminal fluid, which helps transport sperm. It also plays a role in hormone production and helps regulate urine flow.

Colon cancer refers to cancer that develops in the colon, located in the large intestine. It helps pull liquid from the stool back into the body, preparing waste to exit the anus as a bowel movement. As the colon connects to the rectum, many doctors group cancers affecting these areas using the term colorectal cancer.

There may be connections between these two cancers. Those who have or have had prostate cancer in the past may be more likely to have colorectal cancer or precancer as well. Research from 2017 found that males diagnosed with colorectal cancer have a higher risk for prostate cancer. This risk was greater in those under 55 years old.

Similarly, research from 2016 found that people with prostate cancer had a higher risk of having advanced abnormal growths in the colon. Researchers suggested that people with prostate cancer have a colonoscopy to check for these growths at the time of their cancer diagnosis.

Furthermore, genetics and family history can play a role in both types of cancer, and in some cases may increase the likelihood of developing both types. For example, Lynch syndrome is a common cause of colorectal cancer, and evidence suggests that the condition may also increase the risk of other cancers, including prostate cancer.

Some similarities between prostate and colon cancer may include:

Risk factors

The two cancer types may share some risk factors. For example, the risk for both colorectal cancer and prostate cancer increases with age. Evidence suggests that family history and racial backgrounds can also increase the risk of both prostate and colorectal cancer. Additionally, conditions such as Lynch syndrome are also associated with both types.

Studies suggest that people who receive radiation therapy for prostate cancer may have a higher risk of developing colorectal cancer as secondary cancer.

Furthermore, factors such as diet, smoking, and obesity may also influence the risk of both conditions.

Occurrence

Both prostate cancer and colorectal cancers are common conditions and common causes of cancer-related death. Prostate cancer makes up about 13% of all new cancer cases in the U.S., and about 6% of all cancer deaths, while colorectal cancer makes up roughly 8% of all new U.S. cancer cases and about 9% of all cancer deaths.

However, it is worth noting that the above statistics relating to prostate cancer only refer to those with a prostate, while the statistics for colorectal cancer refer to the whole population.

Diagnosis and treatment options

Diagnosing either cancer may involve imaging tests to investigate tissues and tissue biopsies to confirm the diagnosis. Additionally, a doctor may perform tests for certain markers, such as carcinoembryonic antigen (CEA) or prostate-specific antigen (PSA), to help with the diagnosis.

Some treatment options for both cancers may also be similar, such as using chemotherapy or radiation therapy. In some cases, both cancer types may require surgery to remove sections of the prostate or colon that contain cancer.

While the two cancers do share common elements, there are distinct differences between them, including:

Where they occur

The two types of cancer occur in different areas of the body. Colon cancer is a cancer of the bowels, occurring in the large intestine, whereas prostate cancer occurs in the prostate, part of the genitourinary system.

Who they affect

Colon cancer may occur in anyone, but prostate cancer typically only occurs in those born with a prostate. People without a prostate may have structures with a similar function, called Skene’s glands, that some may refer to as the female prostate. In this way, female prostate cancer is possible but exceedingly rare.

The age range of those affected may vary as well. Colon cancer risk may occur at slightly younger ages. The Centers for Disease Control and Prevention (CDC) recommend a person consider screening for colorectal cancer from age 45. Prostate cancer tends to occur in older people. The CDC recommend those aged 55–69 speak with a doctor about screening.

Symptoms

While some cancer symptoms such as fatigue and weight loss may overlap, defining symptoms between the two cancers differ. For example, colorectal cancer may cause symptoms affecting the bowels, such as:

Prostate cancer may cause symptoms affecting urination and ejaculation, such as:

Survival rate

The 5-year survival rate may also vary. For example, the National Cancer Institute estimates the 5-year survival rate for colorectal cancer is about 65%, whereas the 5-year survival rate for prostate cancer approaches 98%.

There are several screening tools doctors may recommend depending on the type of cancer. The screening options for each case will vary based on a doctor’s recommendations and personal preference.

Screening for prostate cancer may involve a blood test to check for PSA, a substance made by the prostate. The levels of PSA in the blood may be higher in those with prostate cancer. Screening may also include a digital rectal exam, which involves inspecting the prostate for lumps or anything else that seems unusual.

For colon cancer, screening will often involve taking stool samples and testing for blood or changes in DNA. A doctor may also use imaging tests such as a colonoscopy, sigmoidoscopy, or CT colonography to check the colon for polyps, abnormal areas, or cancer. A doctor may also measure CEA levels to help with the diagnosis.

It is advisable for people to attend regular cancer screenings following their doctor’s guidance, particularly those at higher risk. Early detection can improve cancer treatment outcomes.

Additionally, making changes to the manageable risk factors for cancer may help reduce cancer risk in some people. These typically involve changes to the diet and lifestyle, such as:

With this said, there is no guarantee that making changes to the diet or lifestyle will eliminate the risk of cancer.

Prostate cancer and colon cancer are two separate and common types of cancer. While they share some similarities, such as certain risk factors, they have many differences, such as some symptoms.

Screening can help to identify both types of cancer early and allow people to receive prompt treatment. Some lifestyle changes may also help to reduce the risk for both types of cancer.