Kanser usus (bowel or colorectal cancer) is cancer of the large bowel, including the colon and rectum, and it is the second most common cancer in Malaysia. Warning signs include a lasting change in your bowel habits, blood in your poo or bleeding from the bottom, tummy pain or a lump, bloating, unexplained weight loss and tiredness from anaemia. These symptoms often have other causes, such as piles, but they should always be checked, because finding bowel cancer early can make it easier to treat. In Malaysia, screening with a simple stool test (iFOBT) is recommended from age 50 to 75 for people at average risk.
What is kanser usus (bowel cancer)?
According to the NHS, bowel cancer is cancer found anywhere in the large bowel, which includes the colon and rectum. It is also called colorectal cancer, and in Malay kanser usus or kanser kolorektal.
Bowel cancer is very common in Malaysia. According to the World Health Organization's GLOBOCAN 2024 estimates for Malaysia:
- colorectal cancer was the second most common cancer overall, with 7,693 new cases (14.1% of all new cancers), after breast cancer;
- it was the second most common cancer in both men (16.4%, after lung cancer) and women (12.0%, after breast cancer);
- it caused 3,726 deaths, the third highest number of cancer deaths.
Malaysia's Ministry of Health clinical practice guidelines also describe colorectal cancer as the second most common cancer in Malaysia.
Tanda kanser usus: what are the symptoms?
According to the NHS, symptoms of bowel cancer may include:
- changes in your poo, such as softer poo, diarrhoea or constipation that is not usual for you;
- needing to poo more or less often than is usual for you;
- blood in your poo, which may look red or black;
- bleeding from your bottom;
- often feeling like you need to poo, even if you have just been to the toilet;
- tummy pain;
- a lump in your tummy;
- bloating;
- losing weight without trying;
- feeling very tired or short of breath, which are signs of anaemia that can be caused by bowel cancer (see our guide to kurang darah).
Some of these symptoms are very common and can be caused by other conditions, such as sembelit or cirit-birit. Having them does not definitely mean you have bowel cancer, but it is important to get checked. Pay particular attention to changes that are not usual for you.
Kanser usus or buasir: how can you tell?
According to the NHS, piles (buasir), swollen blood vessels in and around the anus, are one of the common causes of bleeding from the bottom (see our guide to buasir). But blood in your poo or bleeding from the bottom is also one of the main symptoms of bowel cancer, so get it checked by a doctor rather than assuming it is piles.
- Do not assume bleeding is "just buasir", especially if it is new, keeps happening, or comes with other symptoms such as a change in bowel habits, tummy pain or weight loss.
- A doctor can examine you and decide whether you need further tests.
The NHS advises trying not to be embarrassed: doctors and nurses are used to talking about these symptoms.
When are bowel symptoms urgent?
See a doctor if you have any symptoms of bowel cancer.
Ask for an urgent appointment, according to the NHS, if:
- your poo is black or dark red;
- you have bloody diarrhoea.
Call 999 or go to the emergency department if:
- you are bleeding non-stop from your bottom;
- there is a lot of blood or you see large blood clots when you poo.
Do not drive yourself; ask someone to take you or call 999 for an ambulance.
Who is more likely to get bowel cancer?
It is not always known what causes bowel cancer, but it can be caused by genetic changes, lifestyle and environmental factors. According to the NHS, you may be more likely to get bowel cancer if:
- you are over 50;
- you smoke;
- you are overweight;
- a close relative has had bowel cancer;
- you have inflammatory bowel disease, such as Crohn's disease or ulcerative colitis;
- you have small growths in your bowel called bowel polyps;
- you have an inherited condition such as Lynch syndrome or familial adenomatous polyposis (FAP).
Saringan kanser usus: who should be screened in Malaysia?
Screening looks for signs of bowel cancer before you have any symptoms, when it may be easier to treat. Malaysia's Ministry of Health clinical practice guidelines on colorectal cancer recommend:
| Group | Screening recommendation |
|---|---|
| Average risk: no family history, aged 50 and over | Screening offered from age 50 until 75; the stool test iFOBT is the preferred method |
| Moderate or high risk: for example a family history of bowel cancer, such as a parent, brother, sister or child who had it | Colonoscopy is the screening method |
| Family history suggesting an inherited bowel cancer syndrome | Referral to a clinical genetics service for genetic risk assessment |
What is iFOBT? The immunochemical faecal occult blood test (iFOBT), also called the faecal immunochemical test (FIT), checks a small sample of poo for blood that you cannot see. You collect the sample yourself using a kit. Ask your doctor or klinik kesihatan whether you are due for screening. Screening is for people without symptoms; if you have symptoms, see a doctor rather than waiting for a screening test.
How is bowel cancer diagnosed?
According to the NHS, a doctor will ask about your symptoms, general health and family history, and may:
- feel your tummy and do a rectal examination (a gloved finger inside your bottom to check for lumps); you can ask for a male or female doctor or nurse, and for someone else to be in the room;
- ask for a poo sample or a FIT home test kit, and a blood test.
If cancer is suspected, the main test is a colonoscopy, where a thin, flexible tube with a camera is used to look inside your bowel. It may be uncomfortable but should not be painful, and you will be offered a sedative and painkillers. A small sample of the bowel lining (a biopsy) may be taken. If bowel cancer is found, CT, MRI or PET scans, blood tests and genetic tests can show how far it has spread and guide treatment.
How is bowel cancer treated?
According to the NHS, treatment depends on the size of the cancer, whether it is in the colon or rectum, whether it has spread, whether it has certain genetic changes, and your age and general health. You may have a combination of:
- surgery to remove the cancer and part or all of the bowel around it; some people need a colostomy or ileostomy, which may be temporary or permanent;
- chemotherapy, before surgery to shrink the cancer, after surgery to stop it coming back, or if surgery is not possible or the cancer has spread;
- radiotherapy, mainly for cancer in the rectum or cancer that has spread;
- targeted medicines or immunotherapy, sometimes used for advanced bowel cancer that has spread.
If the cancer cannot be cured, treatment aims to slow it down, help with symptoms and help people live longer, with support from a palliative care team.
How can you lower your risk of bowel cancer?
You cannot always prevent bowel cancer, but according to the NHS you can lower your chance of getting it if you:
- eat a healthy diet including at least 5 portions of fruit and vegetables a day;
- eat less red and processed meat;
- stay active and exercise regularly;
- lose weight if you are overweight;
- quit smoking;
- drink less alcohol.
And when you reach 50, ask about screening, as it is the best way to find bowel cancer at an early stage.
Frequently asked questions (FAQ)
What is kanser usus (bowel cancer)?
Kanser usus, or bowel cancer (also called colorectal cancer), is cancer found anywhere in the large bowel, which includes the colon and rectum. It is the second most common cancer in Malaysia: according to GLOBOCAN 2024 estimates, there were 7,693 new cases in Malaysia in 2024, 14.1% of all new cancers.
What are the signs of bowel cancer (tanda kanser usus)?
According to the NHS, symptoms may include changes in your poo that are not usual for you (softer poo, diarrhoea or constipation), needing to poo more or less often, blood in your poo that may look red or black, bleeding from your bottom, often feeling you need to poo even after going, tummy pain, a lump in your tummy, bloating, losing weight without trying, and feeling very tired or short of breath from anaemia.
Is blood in my poo bowel cancer or buasir (piles)?
Piles are a common cause of bleeding from the bottom, but it can also be a sign of bowel cancer, so get it checked rather than assuming it is piles. See a doctor if you have any symptoms of bowel cancer. Ask for an urgent appointment if your poo is black or dark red or you have bloody diarrhoea, and call 999 if you are bleeding non-stop or passing a lot of blood or large clots.
Who should be screened for bowel cancer in Malaysia?
Malaysia's Ministry of Health clinical practice guidelines say screening should be offered from age 50 and continue until 75 for people at average risk, using a stool test called the immunochemical faecal occult blood test (iFOBT). People with a family history of bowel cancer are at moderate or high risk, and colonoscopy is the screening method for them. Ask your doctor or klinik kesihatan about screening.
What is the iFOBT or FIT test?
The immunochemical faecal occult blood test (iFOBT), also called the faecal immunochemical test (FIT), checks a small sample of your poo for blood that you cannot see, which can be a sign of bowel cancer. You collect the sample yourself. If the test finds blood, the usual next step is a colonoscopy, where a thin, flexible tube with a camera is used to look inside the bowel.
Can young people get bowel cancer?
Yes, although you are more likely to get bowel cancer if you are over 50. Your risk is also higher if you smoke, are overweight, have a close relative who has had bowel cancer, have inflammatory bowel disease (Crohn's disease or ulcerative colitis) or bowel polyps, or have an inherited condition such as Lynch syndrome. Whatever your age, get bowel symptoms checked.
Can bowel cancer be prevented?
You cannot always prevent it, but the NHS says you can lower your chance by eating a healthy diet with at least 5 portions of fruit and vegetables a day, eating less red and processed meat, staying active, losing weight if you are overweight, quitting smoking and drinking less alcohol. Screening also helps find cancer early, which may make it easier to treat.
Disclaimer
This article is for general information only and is not a substitute for advice, diagnosis or treatment from a doctor. Health supplements are not intended to diagnose, treat, cure or prevent any disease.
References
- Bowel cancer — NHS
- Symptoms of bowel cancer — NHS
- Causes of bowel cancer — NHS
- Tests and next steps for bowel cancer — NHS
- Treatment for bowel cancer — NHS
- Bleeding from the bottom (rectal bleeding) — NHS
- Bowel cancer screening — NHS
- Quick Reference: Management of Colorectal Carcinoma (Clinical Practice Guidelines) — Ministry of Health Malaysia
- GLOBOCAN 2024: Malaysia fact sheet — International Agency for Research on Cancer (WHO)
