Top Early Warning Signs of Colon Cancer Illustration

Top 10 Early Warning Signs of Colon Cancer (2023)

by | Jul 15, 2023

Colon cancer is the fourth leading cause of cancer-related deaths in the United States, accounting for more than 100,000 new cases each year. It’s a disease that occurs in approximately 1 in 25 adults.

Most colon cancer cases fail to show symptoms until the disease has spread to other parts of the body. However, some early warning signs can raise suspicion and prompt individuals to see a doctor for further testing.

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Early Warning Signs of Colon Cancer

Some of the most common early warning signs of colon cancer include:

  1. Blood in Your Stool
  2. Changes in Bowel Habits
  3. Anemia
  4. Loss of Appetite
  5. Unexplained Weight Loss
  6. Nausea and Vomiting
  7. Diarrhea
  8. Abdominal Pain
  9. Chronic Fatigue
  10. Pelvic Pain

1. Blood in Your Stool

One of the most common early warning signs of colon cancer is blood in your stool. If you notice bright-red blood in your stool, this indicates bleeding in the lower intestinal tract or rectum.

You may also notice maroon or darker-colored bowel movements, which can be a sign of bleeding higher up in the gastrointestinal tract.

While blood in your stool can be caused by other conditions like hemorrhoids or anal fissures, it’s important to consult with a doctor to rule out any serious underlying causes.

2. Changes in Bowel Habits

If you’re experiencing persistent changes in your bowel habits, this could be an early warning sign of colon cancer. Some examples include:

  • Constipation
  • Diarrhea
  • Changes in bowel-movement frequency
  • Incomplete bowel movements
  • Decreased stool thickness

These abnormal bowel changes can be caused by a variety of factors, such as dietary changes, disagreeable foods, and bacterial/viral infections.

However, if they last for more than a few days, it’s best to see a doctor to determine the underlying cause.

3. Anemia

Anemia is a condition characterized by a lack of healthy red blood cells or hemoglobin. These cells are responsible for carrying oxygen to the body’s tissues.

This symptom is common with colon cancer because intestinal bleeding can occur without any noticeable bleeding from the rectum or stool. Therefore, if you’re experiencing fatigue, shortness of breath, or lightheadedness, it could be due to anemia caused by colon cancer.

In this case, it’s important to consult with a doctor for further testing, especially if it’s accompanied by other symptoms on this list.

4. Loss of Appetite

Cancer cells can release substances that alter how your body processes food, leading to a loss of appetite. This explains why weight loss is a common symptom in cancer patients, including those with colon cancer.

Researchers found that this symptom is associated with both metabolic changes and reduced dietary intake. This can occur during both the early and late stages of the disease.

In any case, the sooner you notice this symptom, the better. A loss of appetite can quickly lead to malnutrition and weight loss, which can negatively impact your overall health.

5. Unexplained Weight Loss

Unintentional weight loss is a hallmark sign of multiple types of cancer, including colon cancer. This may occur due to persistent diarrhea or difficulty digesting and absorbing nutrients.

Not to mention, if patients with colon cancer have a loss of appetite, it only makes sense that they may also experience unexplained weight loss.

6. Nausea and Vomiting

Nausea and vomiting are also common symptoms of colon cancer. This is likely due to the fact that cancer cells can release substances that alter how your body processes food.

In addition, a rectal tumor can obstruct the intestines, which can cause a build-up of waste and toxins in the body. This can lead to nausea and vomiting as the body tries to get rid of these harmful substances.

Therefore, if you’re experiencing persistent nausea and vomiting, along with other signs and symptoms, it’s important to see a doctor to potentially rule out colon cancer.

7. Diarrhea

Diarrhea is defined as loose, watery stools that occur more than three times per day. It’s a common symptom of conditions like food poisoning or a stomach virus, but it can also be an early warning sign of colon cancer.

While diarrhea itself is not necessarily a cause for concern, it’s important to consult with a doctor if it lasts for more than a few days or is accompanied by other symptoms on this list.

8. Abdominal Pain

Abdominal pain is a common symptom of many different conditions, but it can also be an early warning sign of colon cancer. As previously mentioned, when cancerous tumors grow in the colon, they can obstruct the intestines and cause a build-up of gas and waste.

This can lead to abdominal pain, distention, cramps, and bloating. In some cases, the pain may be severe enough to warrant a trip to the emergency room.

9. Chronic Fatigue

Chronic fatigue is a hallmark sign of multiple types of cancer, including colon cancer. In fact, researchers found that fatigue occurs in approximately 80% of patients with colorectal cancer, and 30% of patients experience chronic fatigue.

This is especially true in those receiving chemotherapy.

Furthermore, as previously mentioned, colon cancer often leads to malnutrition and weight loss, both of which can contribute to fatigue. So, if you’re experiencing fatigue that is out of the ordinary, it’s important to see a doctor for help determining the underlying cause.

10. Pelvic Pain

Pelvic pain is actually not an early warning sign of colon cancer. If pain occurs in this area, it may indicate that cancerous cells have spread to the pelvic region.

This is a serious complication that requires immediate medical attention. Therefore, it’s especially important to be aware of this symptom if you’ve had intestinal issues in the past.

More research is needed to determine the exact link between colon cancer and pelvic pain; however, a population-based study showed a clear association between the two.

What is Colon Cancer?

Colon cancer, also known as colorectal cancer, is a type of cancer that begins in the large intestine (colon). It typically starts as small, noncancerous clumps of cells called polyps that over time can become colon cancers.


  • Changes in bowel habits
  • Rectal bleeding
  • Abdominal discomfort
  • Fatigue
  • Unexplained weight loss

Risk Factors

  • Older age
  • African-American race
  • Personal history of polyps or colorectal cancer
  • Inflammatory intestinal conditions
  • Low-fiber and high-fat diet
  • Obesity
  • Smoking
  • Alcohol consumption


Colon cancer typically arises from precancerous polyps that form in the large intestine. While the exact cause is unclear, it’s understood that colon cancer occurs when there’s a mutation in the DNA of your cells.

The mutation causes cells to continue dividing even when new cells aren’t needed, leading to the formation of a tumor.

How to Prevent Colon Cancer?

To lower the risk of colon cancer, several steps can be taken:

  • Regular Screening: Regular screening tests like colonoscopies can help detect colon cancer early, when treatment is most likely to be successful.
  • Healthy Diet: Eat a variety of fruits, vegetables, and whole grains which provide vitamins, minerals, fiber, and antioxidants. Limit your intake of red meats and processed meats.
  • Exercise: Regular physical activity can lower your risk.
  • Weight Management: Maintain a healthy weight. If you’re overweight, losing even a small amount of weight can have benefits.
  • Alcohol Moderation: Limit alcohol consumption. It’s suggested that men have no more than two drinks and women have no more than one drink a day.
  • Quit Smoking: Avoid smoking as it’s associated with an increased risk of many types of cancers, including colon cancer.
  • Consider Genetic Testing: If you have a family history of colon cancer, genetic testing can help identify inherited gene mutations, which might increase your risk.

Final Thoughts

Colon cancer is a serious disease that can be life-threatening, which is why it’s important to be aware of the early warning signs. If you experience any of the symptoms on this list, make an appointment with your doctor to get checked out.

The sooner you catch colon cancer, the better your chances are of beating it.

This article is intended for informational purposes only and should not be taken as medical advice. If you have any concerns or questions about your health, please consult a medical professional.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


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