To Book an Appointment

Colon Cancer Symptoms: Early Signs & When to Seek Medical Help

By Dr. Sajjan Rajpurohit in Medical Oncology , Paediatric (Ped)/Medical Oncology , Gastrointestinal & Hepatobiliary Oncology , Head & Neck Oncology , Musculoskeletal Oncology

Apr 02 , 2025 | 3 min read

Colon cancer, also called colorectal cancer, is among the leading causes of cancer-related deaths globally. Early detection is important for improving survival rates and treatment outcomes. Understanding the symptoms of colon cancer can empower individuals to seek medical attention promptly, which is vital for successful treatment.

Colon cancer usually develops slowly over the years, so identifying the signs early is essential for effective treatment. While some symptoms can be associated with other, less serious conditions, it is critical to seek medical advice if they persist or worsen.

Common Symptoms of Colon Cancer

Changes in Bowel Habits: One of the most common and noticeable symptoms of colon cancer is a change in bowel habits. This may include persistent diarrhoea, constipation, or a shift in stool consistency. Individuals may also notice that their stools are not passing as easily or that they feel an incomplete evacuation after a bowel movement. These changes should not be ignored, especially if they persist for several days or weeks. If your bowel habits remain inconsistent or irregular, seeking advice from a healthcare professional is essential.
Blood in the Stool: Blood in the stool is a serious symptom that should never be overlooked. Blood may appear bright red, often signifying that it is coming from the lower colon or rectum, or it may be dark, which could indicate bleeding higher in the colon. Even small amounts of blood should be evaluated by a doctor. If blood is visible in your stool, regardless of the amount, it is essential to seek medical attention right away to rule out colon cancer or other conditions such as haemorrhoids.
Abdominal Discomfort: Persistent abdominal pain, cramping, bloating, or a sensation of fullness can be indicative of colon cancer. Individuals may experience discomfort after eating, and some may feel gassy or unable to relieve pressure. These symptoms can be common to various gastrointestinal problems, but if they persist over time or seem to worsen, it is crucial to investigate further. Colon cancer can cause a blockage or narrowing of the colon, leading to discomfort and digestive disturbances.
Unexplained Weight Loss: Significant and unexplained weight loss is another warning sign of colon cancer. If you are losing weight without changing your diet or physical activity, it could indicate a serious underlying condition. In some cases, colon cancer may lead to weight loss due to changes in metabolism or nutrient absorption or as a result of the body’s response to cancer. If weight loss occurs alongside other symptoms, it is important to see a doctor for a full evaluation.
Fatigue and Weakness: Persistent fatigue or weakness can also be symptoms of colon cancer. Often, this is linked to anaemia, which occurs when a tumour causes internal bleeding, leading to a lack of red blood cells. It is important to seek medical attention if you feel unusually tired or weak, especially when combined with other symptoms such as blood in the stool. Fatigue may also be exacerbated by other cancer treatments, such as chemotherapy, but it’s important to rule out colon cancer or any other underlying issues.
Narrowing of the Stool: Another potential sign of colon cancer is a noticeable change in stool shape. If the stool appears narrower or thinner than usual, it may indicate a blockage or partial obstruction in the colon, possibly caused by a tumour. A change in stool size or shape, especially when accompanied by other symptoms like abdominal discomfort or blood in the stool, should prompt a visit to your healthcare provider for further investigation.

When to Seek Medical Attention

Individuals who experience any of these symptoms, particularly if they persist for more than a few weeks, to seek medical evaluation. Colon cancer is often most treatable when caught early, which is why recognising these symptoms and acting promptly is so crucial. It is also important to be aware of your family history, as individuals with a first-degree relative who has had colon cancer may be at an increased risk. Regular screenings, particularly for those over 45, can also help catch colon cancer before symptoms even appear.

Overall

If you experience any of the symptoms outlined above, it is important to consult with a healthcare provider who can evaluate your condition and, if necessary, recommend appropriate diagnostic tests such as colonoscopy or imaging studies. By recognising these warning signs and seeking prompt medical attention, you can help ensure that colon cancer is detected early when it is most treatable. Prioritising regular screenings, especially for those at higher risk, remains one of the most effective ways to prevent and detect colon cancer early.