Five signs you need a colonoscopy and why you shouldn’t ignore them

Disclaimer: All text and images published in this article are for general information and educational purposes only. It is not a substitute for professional advice. Always consult a registered health professional regarding any health-related diagnosis or treatment options.

Despite what you may have heard about colonoscopy, it is still the “gold standard” of detecting cancer in your colon along with several other gastrointestinal diseases. They are proven to identify potential issues as early as possible, saving thousands of lives every year in Australia. 

Colon cancer (also called bowel cancer or colorectal cancer) is Australia’s second deadliest form of cancer (, 2020). And even though it’s killing more younger people than ever before, a technique as good as a colonoscopy makes colon cancer one of the few types that can be well prevented even before it strikes. 

Here are the five top signs you need a colonoscopy

A woman pressing her hands against her mid-section in pain resulting from a stomach ache

1) A persistent change in your bowel habits 

A persistent and sometimes significant change in your bowel habits can be one of the first few apparent symptoms of colon cancer. These changes can become a concern, especially when accompanied by other symptoms like diarrhoea, constipation, or abdominal pain. 

However, it is worth mentioning that there are many different causes of change in bowel patterns that are not linked to cancer.  

2) 45 is the new 50 for colon cancer screening 

Prompted by recent surges in cases of colon cancer amongst younger people, it is now far from being “an old person’s disease.” In fact, of all diagnosed colon cancer cases in Australia each year, more than 10% of them are individuals under the age of 50 (Bowel Cancer Australia, 2021). 

Furthermore, of all the primary cancer forms in Australia, colon cancer is the only type that has shown a progressively increasing mortality rate since the past decade for people aged 45-49. 

So, the otherwise “young and healthy” individuals wouldn’t know if they’re vulnerable to colon cancer until a colonoscopy can detect that. 

3) Unintentional weight loss 

A sudden loss of weight without even trying can be another reason to do a colonoscopy, as it can possibly suggest colon cancer. 

A sudden and unexpected weight loss of 3 kgs or more within six months is often noticed in people with colon cancer. This can happen because the cancer cells consume much of the body’s energy, and the immune system works too hard to fight off the cancer cells. 

Moreover, a study on weight loss and colon cancer has found that a loss of up to 5 kgs is a warning sign for early-onset colon cancer (Popov, 2015). 

4) Abdominal pain

Many significant organs are located in the abdomen, including the stomach, appendix, gall bladder, kidneys, and pancreas. So, a symptom like abdominal pain can be very vague. It can be mistaken for kidney disease, a possible bowel obstruction, or just mere ingestion. 

But, when your abdominal pain is persistent and doesn’t improve on its own, it can suggest a more serious gastrointestinal disease.  With the use of a colonoscopy, your doctor can determine the cause of the pain and begin to understand our symptoms (Queensland Gastroenterology, 2021). 

5) Rectal bleeding 

Rectal bleeding, a symptom varying from mild to severe, is commonly seen for many gastrointestinal diseases, including colon cancer and inflammatory bowel disease. 

The bleeding can also start due to several other reasons. It can be due to swollen veins in the rectum (haemorrhoids), a tear of the colon skin, the growth of polyps, and so on. 

But with the help of colonoscopy, your doctor will be able to examine the inside of your colon and look for possible causes. They will be able to diagnose if you’re suffering from a particular reason for rectal bleeding and provide treatment appropriately. 

Why ignoring a colonoscopy can be fatal

Colonoscopy makes it possible for your clinician to study what’s going on inside your colon. It enables them to examine the entire colon. Although there are other ways to diagnose digestive health issues, only a colonoscopy can make it possible to remove a suspicious polyp or cancer immediately. 

In this way, colonoscopy can look for potential diseases, assist in removing polyps, and preventing their further growth. People might be scared by the idea of colonoscopy, but the benefits of the procedure are undeniable, so much so that it has made many colon diseases preventable

Bowel Cancer Australia, (2021). Young onset bowel cancer(Never2Young). More information here. (2020). Understanding Australia’s second deadliest cancer: Rebecca’s story. More information here. 

Popov, V. (2015). Weight loss may be a warning sign of colorectal cancer. More information here. 

Queensland Gastroenterology (2021). Brisbane Colonoscopy. More information here. 

Authored by:

Queensland Gastroenterology and Professor Darrell Crawford



Further Reading: Gastrointestinal and Liver Health

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