It is one of the deadliest cancers, killing nearly 80,000 people each year in the UK and US.
But as with most tumors, not everyone knows the telltale symptoms.
Experts say the lack of awareness can hamper survival, with early diagnosis being key to beating the disease.
Here, MailOnline highlights the warning signs of colon cancer so you know when to speak to a professional.
It comes after BBC Radio 1 DJ Adele Roberts said early treatment ‘saved my life’.
The 44-year-old revealed she was undergoing treatment in October 2021 following her stage two diagnosis.
She later underwent surgery to remove a tumor and began using an ostomy pouch. Last June, she announced she was cancer-free.
Colon cancer can cause you to have blood in your stool, a change in bowel habits, a lump in your bowel that can cause blockages. Some people also suffer weight loss as a result of these symptoms
Bleed
Finding blood in your poop can be alarming.
Bright red blood — indicating it’s fresh — can be caused by hemorrhoids.
But drops of blood in your stool can also be caused by noncancerous growths called polyps, according to Bowel Cancer UK.
However, dark or black blood can be a sign of cancer, Cancer research says.
This is because intestinal tumors, which are usually located higher up in the digestive tract, can cause internal bleeding.
Anyone experiencing blood in their poop should see their doctor to find out what’s causing it.
Screening programs also check for hidden blood in the poop and also for polyps, as these can develop into cancer.
Change in bowel habits
Changes in your usual bowel habits can also be a possible warning sign of colon cancer.
It can be as simple as having to go to the toilet more often or feeling like you’re not completely emptying your bowels.
“A possible indicator of bowel cancer is any significant change in your defecation habits – which can vary from person to person,” says bowel surgeon James Kinross of King Edward VII Hospital in London.
He added, “For example, defecating more often than usual, or having looser, runnier stools.
“This would probably be related to an external factor such as stress, eating more fiber or a change in diet, but it’s worth getting yourself checked if the problem persists.”
This habit change may be caused by the presence of a tumor causing partial obstruction in the bowel and constipation.
It can also cause diarrhea if the tumor leaks fluid into your intestines.
The change can happen for no apparent reason, and if it continues for more than three weeks, you should get it checked out by your doctor, says Macmillan.
Weight loss
Although an uncommon sign of colon cancer, unexplained weight loss is still something to watch out for and report to your doctor.
This symptom could be due to a tumor that is making you feel sick or bloated, says Bowel Cancer UK.
A tumor can also block the gut, which can cause pain in the stomach that prevents you from eating, the charity explains.
Dr. Kinross said: ‘Abdominal pain can have a wide variety of causes, from muscle fatigue to menstrual cramps.
But it can also be a sign of colon cancer.
“Discomfort or bloating that is always caused by eating — which can cause you to eat less and in turn lose weight — is something that should be evaluated by a medical professional.”
Fatigue
Colon cancer can make you feel tired.
This may be because the tumor is bleeding internally, which can develop into anemia – when there is a shortage of red blood cells in the body.
You may feel very tired and have pale skin due to a domino effect.
Anemia can also cause dizziness and shortness of breath, according to Macmillan.
Tumors often develop into palpable masses. Your doctor may be able to feel the lump, which is more commonly found on your right side, says Cancer Research UK
Pain or lump
A lump or pain in your stomach area or anus is a warning sign of a tumor in the intestine.
Your doctor may be able to feel the lump, which is more commonly found on your right side, says Cancer Research UK.
It can make you feel like you have to exert yourself even after you’ve opened your bowels.
Dr. Kinross said, “Although this is probably benign, it could indicate a malignant tumor.”
You should see your GP if these symptoms don’t go away, especially if it affects how you eat and sleep, says Bowel Cancer UK.
intestinal obstruction
Pain, bloating, and nausea can sometimes be caused by an intestinal obstruction, such as a tumor.
Cancer Research UK warned that people experiencing this symptom should immediately see their GP or go to the ED.
It is usually a sign that the cancer has progressed.
It can happen when a tumor puts pressure on the gut, or grows into the nerve supply and damages it.
‘Early detection is one of the best ways to increase your chances of survival from colon cancer,’ says Dr Kinross.
He added, “And while talking about your poop — or bowel movements — may seem embarrassing, doctors are there to listen confidentially and without judgment.
“By talking to them, they can run the necessary tests and treat you as quickly and efficiently as possible.”