Colon cancer, also known as colorectal cancer or colon cancer, is one of the most treatable forms of cancer when caught early. It often begins as small, non-cancerous growths called polyps. Over time, some of these polyps can turn into cancer.
Because symptoms can be subtle or mistaken for common digestive issues like IBS or piles (hemorrhoids), it is vital to know the specific “red flags” that require a medical review.
If you notice any of the following symptoms persisting for three weeks or more, you should consult your GP.
1. Persistent Change in Bowel Habit
This is one of the most frequent early indicators. It isn’t just a one-off bout of constipation or diarrhoea, but a lasting shift in your normal rhythm.
What to watch for: Going to the toilet more often, having looser stools, or a persistent feeling that you haven’t fully emptied your bowels.
Note. Most people are very consistent in their bowel habits, with quite a range – e.g. from 3x a week to 3x a day. But it is a change in this pattern that is significant and should be discussed with your doctor.
2. Blood in the Stool (Haematochezia)
Finding blood in your stool can be frightening, but it is a critical symptom to report.
The Appearance: Bright red blood may come from lower in the colon or rectum. However, dark, black, or tarry stools (melena) are equally concerning, as they indicate bleeding from higher up in the bowel.
Top Tip: Do not assume blood is “just piles.” Even if you have haemorrhoids, a doctor must rule out other causes.
3. Abdominal Pain or Bloating
While many things cause stomach aches, discomfort caused by a tumor in the colon is often persistent.
Sensation: You may experience cramping, gas pain, or a feeling of “fullness” or bloating that doesn’t go away after eating or using the bathroom.
4. Unexplained Weight Loss
If you are losing weight without changing your diet or exercise routine, your body may be reacting to a growing tumor. Cancer cells consume the body’s energy, and a blockage in the colon can also affect how you absorb nutrients.
5. Fatigue and Anaemia
A tumor in the colon can bleed slowly and microscopically over a long period. You might not see the blood, but the constant loss leads to iron-deficiency anaemia.
Symptoms of Anaemia: Feeling unusually tired, weak, or short of breath, and having pale skin.
Screening is designed to find cancer before you have symptoms. In many countries, home testing kits (like the FIT kit) are sent to adults over a certain age.
The FIT Test: This looks for tiny traces of blood in your stool that aren’t visible to the naked eye.
The Result: If your screening is positive, it does not mean you have cancer, but you will likely be referred for a colonoscopy to look inside the bowel.
Most people with these symptoms do not have cancer, but you must “rule it out” to be safe.
Book a GP appointment immediately if:
You have blood in your stool or bleeding from your bottom.
You have a persistent change in bowel habits lasting 3 weeks.
You feel a lump in your abdomen (stomach area).
You are experiencing extreme tiredness for no obvious reason.
What to Expect at the GP
Your doctor will likely perform a physical examination, which may include a digital rectal examination (DRE) to check for lumps. They will also order blood tests to check for anemia and may ask you to provide a stool sample for a FIT test.
| Symptom | Description | Action |
| Bowel Habit Change | Looser stools or going more often | See GP after 3 weeks |
| Blood in Stool | Bright red, dark, or tarry | Urgent GP Review |
| Abdominal Pain | Persistent bloating or cramping | See GP |
| Anemia/Fatigue | Feeling weak, pale, or tired | Blood test via GP |
| Weight Loss | Dropping pounds unexpectedly | See GP |
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