Gastric ulcers and colorectal cancer have several overlapping symptoms, such as diarrhea and blood in the stool. Due to the risks of colorectal cancer, these symptoms warrant a talk with a doctor.

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The symptoms of ulcers and colorectal cancer can sometimes be similar, but these are two very different conditions with different outlooks.

Ulcers and colorectal cancer can both affect your digestive system and its day-to-day function. You may notice symptoms such as changes in your bowel habits, abdominal pain, or blood in your stool.

This article explores the symptoms of these conditions, whether ulcers raise the risk of colorectal cancer, and when to speak with a doctor.

Different types of ulcers (sores) affect different parts of the digestive tract. Their symptoms can vary, and some types are more closely linked to colorectal cancer than others. These include:

  • gastric ulcers that involve the lining of the stomach (they’re also known as peptic or stomach ulcers)
  • duodenal ulcers that affect the upper portion of the small intestine
  • ulcers in the colon from ulcerative colitis (UC), an inflammatory bowel disease (IBD)

Overlapping symptoms

Ulcers and colorectal cancer share some common symptoms.

You might experience:

Symptoms of ulcers

Symptoms more often associated with ulcers include:

Symptoms of colorectal cancer

Symptoms of colorectal cancer often include:

  • diarrhea, constipation, or change in stool consistency that lasts longer than a few days
  • rectal bleeding or blood in the stool
  • persistent abdominal discomfort or cramps
  • weakness
  • unintended weight loss

Research on the connection between stomach ulcers and colorectal cancer is limited. According to one small study from 2018, the H. pylori infection that causes many stomach ulcers could be a risk factor for colon cancer and high risk polyps.

Another 2016 study found that while ulcers may be associated with stomach cancer, there isn’t enough evidence to suggest that they increase your risk of colorectal cancer.

If you have UC, you may also have a higher risk of colorectal cancer. UC is an IBD that causes ulcers in the colon and prolonged inflammation in the lining of the intestines.

It can slightly raise your risk of developing colorectal cancer. Inflammation, the body’s response to injury or infection, can damage cells in your colon. And in the process of repairing this damage, it may lead to cancer. The longer you have UC, the higher your risk is.

There isn’t enough evidence to suggest that colon cancer causes ulcers. However, some treatments for colon cancer may cause ulcers. A 2017 study reports that participants receiving the cancer medication bevacizumab, along with other treatments, were at increased risk of anal ulcers.

Blood in your stool or rectal bleeding is a symptom that you should take seriously. While blood can be a sign of an ulcer, it’s also a common symptom of colorectal cancer. If you start losing weight without trying and often feel tired or weak, it’s also important to speak with a doctor immediately.

Generally, any unusual changes in your digestive habits warrant a visit to the doctor. Try keeping track of the duration and frequency of symptoms like diarrhea and constipation. Severe pain is another sign you should never ignore, particularly when it’s ongoing and not responding to over-the-counter medications.

Identifying colorectal cancer early is important, so it’s advisable not to ignore any unusual symptoms.

Whether you’re experiencing symptoms or seeking information, speaking honestly with a healthcare professional is important. This will help you understand your personal colorectal cancer risk factors.

Here are a few questions you can ask to gain better insight and make informed choices:

  • What risk factors for colorectal cancer do I have?
  • Do I have UC?
  • What tests or screening methods would you recommend?
  • If I have ulcers, how can I lower my risk of future problems?
  • How is colorectal cancer diagnosed?
  • How often should I be screened for colorectal cancer?
  • What’s my risk of other gastric cancers, like stomach cancer?

Ulcers and colorectal cancer are two different conditions that have some similar signs and symptoms, such as abdominal pain, blood in the stool, and change in bowel habits.

Talk with a doctor if you have any serious or worrying symptoms. They can talk with you about your risk of colorectal cancer.