Colon cancer is one of the most common cancers worldwide and in Singapore, affecting individuals across different ages and backgrounds. One of the main challenges is that the disease often develops quietly, with few or no symptoms in its early stages. By the time symptoms appear, it may already be at a more advanced phase.
This critical gap is why regular screening is non-negotiable. Tests such as colonoscopy remain the most effective way to detect colon cancer early—often before symptoms appear—when treatment is most successful. In this article, we look at what colon cancer is, the symptoms you should be aware of, and when it is important to seek medical advice. Keep reading to learn how recognising these signs early can help protect your long-term health.
What Is Colon Cancer?
Colon cancer begins in the large intestine and often starts as small, benign growths called polyps on the inner lining of the colon, which are commonly detected during a colonoscopy. While many polyps remain harmless, certain types can gradually develop into cancer if they go unnoticed and untreated. As the disease progresses, cancerous cells may grow through the layers of the colon wall and potentially spread to nearby tissues or other organs.
Several factors can increase the risk of developing colon cancer, including:
- Age: Risk rises substantially after age 50.
- Family history: Having a close relative with colon or rectal cancer increases your likelihood of developing the disease.
- Personal history: A previous diagnosis of colorectal polyps or colon cancer raises the chance of recurrence.
- Diet: Frequent consumption of red or processed meats and a low-fibre diet may contribute to inflammation and slower digestion, which can increase risk.
- Lifestyle habits: Smoking, excessive alcohol intake, limited physical activity and obesity are associated with a higher likelihood of developing colon cancer.
- Inflammatory bowel disease (IBD): Chronic conditions such as ulcerative colitis and Crohn’s disease can cause long-term inflammation in the colon, which may raise cancer risk.
Recognising Colon Cancer Symptoms
Colon cancer often develops quietly, with little to no warning signs in its early stages. When symptoms do appear, they may vary from person to person and can easily be mistaken for other digestive issues. Key symptoms to watch for include:
Changes in Bowel Habits
Ongoing diarrhoea, constipation or stools that appear unusually narrow may signal a partial blockage in the colon. Some individuals may also feel as though their bowel movement is incomplete due to a growth affecting normal bowel function.
Visible Blood in the Stool
Bright red blood may indicate bleeding in the lower digestive tract. While this can be caused by several conditions, including haemorrhoids, it should always be evaluated by a healthcare professional.
Unexplained Weight Loss
A significant drop in weight without changes in diet or activity level can occur when the body is using extra energy to cope with illness. Tumours may also interfere with nutrient absorption, contributing to weight loss.
Abdominal Pain or Discomfort
Cramping, gas or bloating can occur when a tumour begins to narrow the colon and disrupt digestion. Unlike occasional digestive discomfort, this pain often persists or recurs.
Fatigue and Weakness
Chronic blood loss from the digestive tract may lead to anaemia, which can cause persistent tiredness not relieved by rest. As anaemia worsens, you may also notice shortness of breath, dizziness or a reduced ability to carry out everyday activities.
Changes in Appetite or Difficulty Digesting Certain Foods
A reduced appetite or discomfort after eating, particularly with heavier or harder-to-digest foods, may occur if a tumour affects digestion or bowel movement.
When to Seek Medical Advice
Persistent or unusual changes in your digestive health that last more than a few weeks should be taken seriously. This is especially true for individuals aged 45 and above, or for those with known risk factors such as a family history of colorectal cancer. Seeking prompt medical attention allows a general practitioner or colorectal specialist to assess your symptoms and identify the underlying cause.
If you are experiencing symptoms or have concerns, do not delay seeking care. Contact our clinic today to book a consultation.
FAQs About Colon Cancer Symptoms
Are changes in bowel habits always a sign of colon cancer?
No, changes in bowel habits are not always a sign of colon cancer. Changes such as diarrhoea and constipation can result from many benign conditions, including infections, diet or irritable bowel syndrome. However, any persistent, unexplained and lasting change in your normal routine must be evaluated to rule out colon cancer or other serious issues.
Can symptoms come and go?
Yes, colon cancer symptoms can and often do come and go, especially in the early stages. This symptom fluctuation can be dangerous, as many people may not realise the changes could signal a more serious underlying problem. Even if symptoms seem mild or temporary, it is important to pay close attention to your body and seek medical advice promptly.
Are younger individuals at risk of colon cancer?
Yes. Although colon cancer is more common in people aged 50 and above, cases among younger adults have been increasing worldwide. Factors such as family history, lifestyle habits and certain medical conditions can contribute to this rising trend.