Colorectal (Colon) Cancer Symptoms

By Dr. Surender Kumar Dabas in Gastrointestinal (GI) Cancer Programme

Jan 18 , 2024 | 12 min read

Colon cancer, also known as colorectal cancer, is a type of cancer that affects the colon or rectum. It typically starts as small growths called polyps, which can eventually become cancerous if left untreated. This disease is one of the most common types of cancer, affecting millions of people worldwide.

Detecting colon cancer in its early stages is crucial for successful treatment and improved survival rates. However, colon cancer symptoms are often not apparent in the early stages of the disease. This is why regular screenings, such as colonoscopies, are recommended for individuals over the age of 45 or those with a family history of colon cancer. During a colonoscopy, a doctor examines the lining of the colon and rectum for any abnormalities or polyps. If polyps are found, they can be removed during the procedure to prevent them from developing into cancer.

Colon cancer is quite common. In fact, it is the third most commonly diagnosed cancer in both men and women globally. According to recent statistics, about 1 in 23 men and 1 in 26 women will develop colon or rectal cancer at some point in their lives. The risk of developing this type of cancer increases with age, with most cases diagnosed in individuals over the age of 50. However, it's important to note that younger individuals can also be affected by colon cancer.

What are Colon Cancer Symptoms?

Early detection and treatment can greatly improve outcomes of colon cancer. By being aware of the common and less common colon cancer symptoms, one can take proactive steps towards prevention and seek medical attention if necessary.

Common Symptoms of Colon Cancer

  • Changes in bowel habits: One of the most noticeable signs of colon cancer is a change in bowel habits. This could include sudden or persistent changes in the frequency, consistency, or appearance of the stool.

  • Rectal bleeding: Blood in the stool or rectal bleeding can be an alarming symptom. While it may indicate other conditions, such as heamorrhoids, it's important to have it evaluated by a doctor.

  • Diarrhoea and constipation: Alternating bouts of diarrhoea and constipation that last for an extended period should not be ignored. These changes may be indicative of an underlying issue, including colon cancer.

  • Persistent abdominal pain: Continuous discomfort or pain in the abdomen, particularly if it is accompanied by other symptoms, should be taken seriously.

  • Tenesmus: The feeling of incomplete bowel movements or the constant urge to have a bowel movement without producing results is known as tenesmus. It can be a sign of colon cancer.

  • Fatigue and weakness: Unexplained fatigue and weakness can sometimes be associated with colon cancer due to the body's immune response to the disease.

Less Common but Significant Symptoms

  • Narrow stools: If a person notices that the stools have become consistently narrower than usual, it could be a sign of a blockage caused by colon cancer.

  • Bowel obstruction: Complete or partial blockages in the colon can cause severe abdominal pain, bloating, and changes in bowel movements that require immediate medical attention.

  • Persistent gas and bloating: Excessive gas and bloating that persist despite dietary changes may be a symptom of colon cancer.

  • Jaundice: Yellowing of the skin and eyes, known as jaundice, can occur if colon cancer spreads to the liver.

  • Nausea and vomiting: Persistent nausea and vomiting, especially in combination with other symptoms, should not be ignored.

  • Unexplained loss of appetite: A significant decrease in appetite that is not related to any other obvious cause should be investigated by a doctor.

  • Pelvic pain: In advanced cases, colon cancer may cause pelvic pain or discomfort.

It's important to remember that these colon cancer symptoms can also be caused by other conditions. However, if one experience any of these symptoms persistently or if one has concerns about his/her health, it's crucial to consult with a doctor. Regular screenings and discussions with one's doctor can help detect colon cancer early when it is most treatable.

Colon Cancer Symptoms in Different Types


Adenocarcinoma is the most common type of colon cancer, accounting for approximately 95% of cases. It begins in the cells that line the inside of the colon and rectum. While it's vital to acknowledge the seriousness of this disease, it's also crucial to provide hope by discussing advancements in treatments and improving survival rates.

Here are some key symptoms of adenocarcinoma, which should be recognised as potential warning signs:

  • Change in bowel habits: If an individual notices a persistent change in his/her bowel movements, such as diarrhoea or constipation that lasts for more than a few days, it may be a sign of colon cancer.

  • Blood in stool: The presence of blood in the stool can indicate various gastrointestinal issues, including colon cancer. This can manifest as dark, tarry stools or bright red blood.

  • Abdominal pain or discomfort: Persistent abdominal pain or cramping that doesn't go away with over-the-counter remedies could be an indication of colon cancer.

  • Unexplained weight loss: Losing weight unintentionally and without any changes in diet or exercise could be a cause for concern and should be evaluated by a healthcare professional.

  • Fatigue and weakness: Feeling tired and weak despite getting enough rest can be a symptom of many conditions, including colon cancer.

Gastrointestinal Carcinoid Tumours

Gastrointestinal carcinoid tumours are a rare type of cancer that develops in the neuroendocrine cells of the digestive tract. While they can occur anywhere in the gastrointestinal system, they are most commonly found in the appendix, small intestine, or rectum. These tumours produce hormones that can cause a variety of symptoms, depending on their location and size.

Some common symptoms of gastrointestinal carcinoid tumours include:

  • Abdominal pain or cramping: This is often described as a dull ache or discomfort.

  • Diarrhoea: This can be chronic or intermittent.

  • Flushing: Skin flushing, particularly on the face and neck, may occur due to hormonal changes caused by the tumour.

  • Wheezing or shortness of breath: Carcinoid tumours can produce substances that cause bronchospasm, leading to wheezing or difficulty breathing.

  • Rectal bleeding: The tumour may cause bleeding, resulting in blood in the stool.

  • Changes in appetite and weight loss: Loss of appetite and unintentional weight loss are common symptoms.

Gastrointestinal Stromal Tumours

Gastrointestinal stromal tumours (GISTs) are a type of tumour that can occur in the colon. While GISTs are relatively rare, it's important to be aware of the symptoms so that one can seek medical attention if needed.

Here are some common symptoms associated with gastrointestinal stromal tumours:

  • Abdominal pain or discomfort: Persistent pain or discomfort in the abdomen may be an indication of a gastrointestinal stromal tumour.

  • Blood in the stool: GISTs can cause bleeding in the digestive tract, resulting in blood in the stool or black, tarry stools.

  • Fatigue and weakness: GISTs can lead to anaemia due to chronic bleeding, resulting in fatigue and weakness.

  • Unexplained weight loss: If an individual is losing weight unintentionally and without any apparent cause, it's important to consult with the doctor.

  • Feeling full quickly or difficulty swallowing: GISTs located in the stomach may cause early satiety (feeling full after eating a small amount) or difficulty swallowing.


Lymphoma is a type of cancer that affects the lymphatic system, which is a part of our immune system. It can occur in the lymph nodes, spleen, bone marrow, and other parts of the body. Lymphoma can affect people of all ages, but it is more commonly diagnosed in individuals between the ages of 15 and 35, as well as those over the age of 55.

Symptoms of lymphoma can vary depending on the type and stage of the disease. Symptoms of lymphoma of the colon may include:

  • Abdominal pain or discomfort: This can range from mild cramping to severe pain.

  • Changes in bowel habits: This includes diarrhoea, constipation, or changes in the size and shape of stools.

  • Blood in the stool: This can be bright red or dark and tarry.

  • Unexplained weight loss: Lymphoma can cause a loss of appetite and unintentional weight loss.

  • Fatigue: Feeling tired and lacking energy is a common symptom.

  • Lumps or swelling in the abdomen: Enlarged lymph nodes may be felt as lumps or swelling in the abdomen.

When to Seek Medical Attention?

If one experiences any colon cancer symptoms, it is important to seek medical attention promptly. While these symptoms may not always indicate colon cancer, it is crucial to have them evaluated by a doctor to rule out any potential issues and ensure early detection and treatment if necessary.

According to the Indian Council of Medical Research (ICMR), colon cancer is the third most common cancer among men worldwide. Each year, thousands of individuals are diagnosed with this disease, and unfortunately, many cases are not detected until the cancer has reached advanced stages. By seeking timely medical evaluation, one can improve his/her chances of a successful treatment outcome. When colon cancer is caught early, before it spreads to other parts of the body, the survival rates are significantly higher. In fact, studies have shown that the five-year survival rate for localised colon cancer that has been detetcted early is over 90%.


In conclusion, by being aware of colon cancer symptoms and risk factors associated with colon cancer, individuals can take proactive steps to protect their health. Taking action and seeking medical advice can significantly improve one's chances of early detection and successful treatment. Stay informed, prioritise health and together we can fight against colon cancer.

Frequently Asked Questions

1. Is colon cancer curable?

Yes, colon cancer can be curable, especially if it is detected in its early stages. Treatment options for colon cancer include surgery, chemotherapy, radiation therapy, and targeted therapy. The effectiveness of treatment varies depending on the stage of the cancer and individual factors.

2. How is colon cancer detected?

Colon cancer can be detected through various methods, including:

  • Colonoscopy: A procedure that allows doctors to examine the entire colon and rectum. During a colonoscopy, any abnormal growths or polyps can be removed and biopsied.

  • Stool tests: These tests can detect blood or DNA changes in the stool that may indicate the presence of colon cancer.

  • Imaging tests: Such as CT scans, MRI scans, or PET scans, these tests provide detailed images of the colon and can help identify tumours or other abnormalities.

3. What age does colon cancer start?

Colon cancer can occur at any age, but it is more commonly diagnosed in people over the age of 50. However, recent studies have shown an increase in cases among younger individuals. It is recommended to start regular screenings for colon cancer at age 45 for most individuals, while those with a family history may need to start earlier.

4. Can stool tests detect colon cancer?

Stool tests can be effective in detecting colon cancer. These tests look for blood or DNA changes in the stool that may indicate the presence of cancer. However, it is important to note that these tests are not definitive and should be followed up with further diagnostic procedures like a colonoscopy if positive results are obtained.

5. Can colon cancer lead to death?

Unfortunately, yes, colon cancer can lead to death if left untreated or if diagnosed at an advanced stage. However, with early detection and appropriate treatment, the survival rates for colon cancer have been improving significantly over time. It is essential to prioritise regular screenings and maintain a healthy lifestyle to reduce the risk of colon cancer and increase the chances of successful treatment.

6. Why is colon cancer so common?

Colon cancer is one of the most common types of cancer worldwide. Several factors contribute to its prevalence, including:

  • Age: The risk of developing colon cancer increases with age.

  • Lifestyle factors: Poor diet, lack of physical activity, obesity, and smoking can increase the risk of developing colon cancer.

  • Family history: People with a family history of colon cancer or certain genetic conditions, such as Lynch syndrome or familial adenomatous polyposis (FAP), have a higher risk.

  • Inflammatory bowel disease: Conditions like ulcerative colitis or Crohn's disease can increase the risk of developing colon cancer.

  • Race and ethnicity: Certain racial and ethnic groups, such as African Americans and Ashkenazi Jews, have a higher incidence of colon cancer.

7. What not to eat with colon cancer?

While there is no specific food that can directly cause or cure colon cancer, it is important to adopt a healthy diet to reduce the risk. Here are some dietary recommendations:

  • Limit processed meats: Avoid consuming processed meats like bacon, sausages, hot dogs, and deli meats that have been linked to an increased risk of colon cancer.

  • Reduce red meat consumption: Limit the intake of red meat, especially when it is processed or charred.

  • Increase fibre intake: Include more fruits, vegetables, whole grains, and legumes in your diet to promote a healthy digestive system.

  • Stay hydrated: Drink plenty of water and avoid sugary drinks.

  • Limit alcohol consumption: Excessive alcohol consumption has been linked to an increased risk of colorectal cancer.

8. What fruits fight colon cancer?

Certain fruits are rich in antioxidants and other compounds that may help reduce the risk of colon cancer. Here are some examples:

  • Berries: Blueberries, raspberries, strawberries and blackberries are packed with antioxidants that may help prevent colon cancer.

  • Citrus fruits: Oranges, grapefruits, lemons and limes are high in vitamin C and other beneficial compounds.

  • Apples: Apples are a good source of fiber and contain bioactive compounds that have been associated with a reduced risk of colon cancer.

  • Pomegranates: Pomegranates are rich in antioxidants and have been shown to inhibit the growth of colon cancer cells in some studies.

9. Is there a difference between colon cancer and colorectal cancer?

No, there is no difference between colon cancer and colorectal cancer. These terms are often used interchangeably to refer to cancer that starts in the colon or rectum. The colon is the large intestine, while the rectum is the last few inches of the large intestine.

10. What are the dietary and lifestyle factors that may increase the risk of colon cancer?

Several dietary and lifestyle factors can increase the risk of developing colon cancer:

  • Poor diet: A diet high in red and processed meats, low in fiber, fruits, and vegetables can contribute to an increased risk.

  • Sedentary lifestyle: Lack of regular physical activity can increase the likelihood of developing colon cancer.

  • Obesity: Being overweight or obese has been linked to a higher risk of colon cancer.

  • Smoking: Smoking tobacco has been associated with an increased risk of various cancers, including colon cancer.

  • Excessive alcohol consumption: Heavy alcohol use can raise the risk of developing colon cancer.

11. Can I prevent colon cancer?

While there is no guaranteed way to prevent colon cancer, certain actions may decrease your risk:

  • Get screened for colon cancer symptoms regularly

  • Maintain a healthy weight

  • Eat a balanced diet

  • Limit alcohol consumption

  • Avoid smoking