Colorectal cancer: Learn the symptoms

23 Mar 2023 05:22pm
picture for illustrative purpose
picture for illustrative purpose

Did you know that colorectal cancer affects about 15 in 100,000 Malaysian men, and is the second most common cancer among Malaysian women?

In Hollywood, the death of actor Chadwick Boseman shed light on colon cancer.

So, what are the symptoms of colon cancer? Sinar Daily talks to KPJ Damansara Specialist Hospital Physician and Gastroenterologist Hepatologist, Datuk Dr. Ahmad Shukri Md Salleh to find out more.

Dr. Ahmad Shukri said colorectal cancer is cancer that happens in the colon and rectum, or the other name of it is colon cancer or large bowel cancer.

It is a disease where the cells in the colon or rectum have grown out of control.

“The symptoms of colon cancer, as other cancers at the beginning of cancer, are initially asymptomatic.

“By the time the patient develops symptoms, the cancer is usually quite significant in terms of the size and also the severity of cancer,” he said.

Related Articles:

KPJ Damansara Specialist Hospital Physician and Gastroenterologist Hepatologist, Datuk Dr Ahmad Shukri Md Salleh - pic credit to Datuk Dr Ahmad Shukri Md Salleh
KPJ Damansara Specialist Hospital Physician and Gastroenterologist Hepatologist, Datuk Dr Ahmad Shukri Md Salleh - pic credit to Datuk Dr Ahmad Shukri Md Salleh

Colorectal cancer typically occurs among those 50 years old and above, and it could be hereditary.

It rarely occurs among those aged 40 and below, unless there is a family history.


Despite how Dr. Ahmad Shukri mentioned that colorectal cancer is typically asymptomatic, there are changes in our health that can indicate symptoms of colorectal cancer.

For example, a sudden change in bowel habits leads to diarrhoea, constipation.

However, there are cases where people experience constipation for years.

“Someone having normal bowel habits and sometimes realised after two to three weeks they started to have a problem with impulsive out motion - they have to strain to defecate.

“Or some patient who has had a normal bowel habit once a day suddenly notices that his bowel is getting loose now, the consistency of the stool becomes loose and sometimes watery, two or three times a day,” he said.

The next symptom is closer to the consistency of the stool where the patient might flush out and spots blood in the faeces.

“Thirdly is the persistent abnormal discomfort where patients would experience cramps or bloating and pain.

“Other than that, someone who has the urge to go to the toilet but flushes out nothing except mucus,” he said.

Apart from the said symptoms, patients would also complain of poor or loss OF appetite, experience weight loss, and feel lethargic.

“There's no certainty or the causes of most colon cancer but it is generally said, the cancer cells started when the healthy cells developed a mutation or changed DNA that caused the cell to grow out of control,” he said.


Despite the asymptomatic symptoms, people should always be self-conscious of their own health and aware of the changes in their body.

It’s undeniable that colorectal cancer is hereditary.

“However, this happens in a small percentage, such as we called it as lynch syndrome or also known as non-polyposis colorectal cancer (HNPCC),” said Dr. Ahmad Shukri.

Another factor that could lead to colon cancer is old age.

However, it could also occur at an even younger age but the majority of the cases affect those older than 50 years old.

“There is a trend that we can see now. People younger than 50 years old are getting colon cancer,” he said.

Dr. Ahmad Shukri also highlights how lifestyle also could inflict colorectal cancer which could be associated with a low fibre and high-fat diet.

“Other risk factors, sedentary lifestyle people who are inactive are more likely to develop colon cancer and diabetes or insulin assistant diabetes have increased cancer, and obesity.

“People who are obese have a higher risk of colon cancer and increase risk of dying of colon cancer, compared with people who have cancer but are of normal weight,” he said.

Smoking, heavy use of alcohol, and also radiation therapy for patients who had been exposed to cancer in the abdomen - also who had radiotherapy done were also at risk of having colon cancer.

However, Dr. Ahmad Shukri said he viewed an increasing trend of ulcerative colitis in Malaysia - where it is a long-term situation of the rectum and colon is inflamed.

Other risk factors involved were the African-American race groups had a greater risk of colon cancer than people of other races.

In Malaysia, the Chinese ethnicity had the highest colorectal cancer incidence which is 27.35 per cent, followed by the Malay 18.95 per cent and Indian 17.55 per cent.

Dr. Ahmad Shukri further shared that the standard age rate incidence of colorectal cancer is 1.33 times higher among males than females.


According to Dr. Ahmad Shukri, early prevention is usually associated with cancer screening - especially for those who have a family history of colon cancer.

“They are advised to do cancer screening as early as 45 to 50 years old.

“Those without the family history of cancer also need to be screened for colon cancer at the age of 50 and above,” he said.

Furthermore, there were also several screening options available - namely the stool test which is to look for blood.

Dr. Ahmad Shukri said a colonoscopy is also recommended in order to detect any changes. This procedure is where a tube tied with a camera at the tip will be inserted in the anus, up to the colon to see the entire view of the organ.

Lastly, a healthy lifestyle that involves daily exercises and healthy food rich in fibre can also minimise the risk of colorectal cancer.