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Symptoms of Colon Cancer You Should Know About

5 min read

By Katherine George

Early detection plays a vital role in improving treatment outcomes for colon cancer. For this reason, we’re exploring the key symptoms of colon cancer so people can detect the warning signs and seek timely medical attention. Given how the symptoms can be misdiagnosed, it’s helpful to research this information online before consulting a doctor.

Change in Stool Shape

Occasionally, a tumor located in the colon can lead to a blockage in the rectum, explains This may result in noticeable changes in the appearance and shape of stool. Instead of its usual form, the source states that the stool may appear unusually thin or string-like, resembling the shape and size of a ribbon.

Moreover, alterations in the texture, color, and overall consistency of the stool may occur. also highlights that these changes can manifest even in the absence of blood in the stool. If you observe such abnormal stool characteristics, consult with a healthcare professional.

Abdominal Pain and Bloating

Abdominal pain that occurs without a known cause, especially if it persists or is severe, is concerning, warns the Cleveland Clinic. Anyone who has this should contact their doctor for further evaluation as it’s one of the common symptoms of colon cancer. While the source notes that many factors can contribute to belly pain, any unusual or recurrent abdominal discomfort should be looked into.

Similarly, there are numerous reasons why a person might fee bloated. However, bloating that persists for more than a week, worsens over time, or occurs alongside other symptoms such as vomiting or bloody stool, could be a result of colon cancer, notes the Cleveland Clinic.

Change in Bowel Habits

While it’s not uncommon to experience a change in bowel habits from time to time, if it persists for more than a few days, it’s something to take note of. The reason for this is because modifications in bowel habits can serve as potential indicators of colon or rectal cancer, warns Johns Hopkins Medicine. Some of the most common changes to look for are an onset of new constipation or diarrhea or feeling of incomplete bowel emptying, notes the source. Johns Hopkins Medicine also states that alterations in frequency, size, and caliber of bowel movements can be red flags.

According to the source, occasional bowel changes can be attributed to factors like dietary adjustments, certain foods, or viral/bacterial infections. However, it is crucial to seek medical attention if any new or unexplained changes that persist.

Fatigue and Weakness

The presence of colon cancer can result in feelings of extreme exhaustion, depletion, and weakness, says The fatigue associated with cancer can leave a person constantly and profoundly tired. This exhaustion persists even after periods of rest or adequate sleep. While excessive fatigue is more prevalent in advanced stages of colon cancer, the source notes that it can occur in earlier stages.

This level of exhaustion may stem from various factors such as the tumor utilizing the body’s energy for continued growth, intestinal bleeding leading to anemia, or inflammation within the body. recommends anyone with this level of fatigue consult with a doctor.

Bloody Stool and Rectal Bleeding

Observing blood in the toilet after a bowel movement can be concerning. This may happen when wiping or in the color of the stool (i.e. dark or bright red). Keep in mind that the presence of blood in stool doesn’t automatically indicate colon cancer. For example, the Cleveland Clinic points out that hemorrhoids, anal tears, or even consuming beets can alter stool. Nevertheless, it is always recommended to seek guidance from a healthcare professional whenever there is blood in or on stool.

John Hopkins Medicine provides tips to help differentiate between bleeding as a result of colon cancer or hemorrhoids. For example, hemorrhoid-related symptoms tend to be intermittent with flare-ups and remissions. On the other hand, rectal bleeding from cancer generally persists or intensifies and may also be accompanied by pain.

Loss of Appetite

A decrease in appetite is a prevalent symptom observed in various types of cancer, including colon cancer. In the case of colon cancer, points out that it can occur due to multiple reasons:

  • Obstruction of the colon by the tumor can hinders the proper digestion of food. According to the source, this leads to a sensation of fullness, even without having eaten a substantial amount.
  • Release of hormones by cancer cells or the tumor itself affects the body’s perception of hunger and transmission of hunger signals to the brain.
  • Nausea and diarrhea can also have an impact on appetite, making individuals less inclined to consume food.

When experiencing a loss of appetite in the context of colon cancer, again advises consulting with a doctor.

Nausea and Vomiting

When a tumor in the colon or rectum obstructs the bowel, it can impede the normal passage of waste materials, explains Johns Hopkins Medicine. As a result, the person will feel nauseous and may even experience vomiting. This bowel obstruction may also lead to additional symptoms such as abdominal cramps, bloating, and constipation, adds the source.

It’s important to recognize that nausea and vomiting can be symptoms of various conditions, both benign and serious. Johns Hopkins Medicine suggests that people who consistently experience nausea, show signs of dehydration, or have been vomiting for over 24 hours, seek medical attention.

Unintentional Weight Loss

Individuals with colon cancer may experience unintended weight loss without any effort. According to, this involuntary weight loss can be due to various factors:

  • The tumor’s interference with the normal digestion and absorption of food leads to the breakdown of stored fat and muscle tissue in the body.
  • Colon cancer can disrupt the production of digestive enzymes. This makes it challenging for the body to effectively absorb essential nutrients.
  • Cancer cells can trigger inflammation and alter metabolic processes.
  • Symptoms like diarrhea and loss of appetite can diminish the frequency of meals.

Senior Managing Editor

Katherine is the Senior Managing Editor of ActiveBeat and Childhood. She is constantly striving to live a more active and healthy life, from eating healthy, exercising, and just spending more time outdoors. She enjoys cooking (with wine), walking her dog, reading, and recently joined a yoga studio!

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