Don’t Ignore Abnormalities In Your Bowel Movements – They Could Be Signs Of Colorectal Cancer

Been experiencing stomach ailments or a change in bowel habits lately? In recent years, I’ve seen more patients coming to me with bowel movement problems. While most aren’t serious issues, having bowel movement issues too frequently or experiencing certain symptoms can mean a bigger health problem – like colorectal cancer. Before you brush aside the possibility, here are some statistics that will show how common colorectal cancer actually is.

A 2018 report by the Singapore Cancer Registry1 found it to be one of the 3 leading cancers diagnosed in Singapore, regardless of gender and ethnicity. In fact, colorectal cancer is responsible for approximately 1 in 6 of all cancer diagnoses in Singaporean men and 1 in 7 in Singaporean women, with Chinese men and women being most at risk.

So how do you know if abnormal bowel movements are a sign of something more serious? Read on to find out.

What Do Abnormal Bowel Movements Mean, And How Are They Related To Colon Cancer? 

While the definition of abnormal bowel movements varies from individual to individual, in general, normal bowel movements would be stools that are easy to pass, typically brown in color, with frequency of at least once in 3 days.

Typically, here are the 3 factors to look out for in terms of bowel movement changes:

Colour of stools

  • black, tarry stools
  • clay-colored stools
  • deep red stools
  • white-colored stools

Consistency of stools

  • dry stools
  • hard stools
  • mucus or fluid that leaks out around the stool
  • watery, loose stools (known as diarrhea)

Frequency of bowel movements

  • No bowel movement for more than three days 
  • Experiencing diarrhea for longer than a day

Signs And Symptoms Of Colon Cancer 

Beyond a persistent change in your bowel habits, in terms of colour, consistency or frequency, here are some other signs2 of colon cancer that you should look out for:

  • Rectal bleeding or blood in your stool
  • Persistent abdominal discomfort, such as cramps, gas or pain
  • Feeling bloated or uncomfortable
  • Having an urge to have a bowel movement when there is no need to have one
  • A sensation that your bowel doesn’t empty completely
  • Weakness or fatigue
  • Unexplained weight loss
  • Anemia

Am I At Risk Of Colon Cancer? 

If you’re over 50, the risk3 of getting colorectal cancer increases quite significantly. 

Other risk factors include having:

  • Inflammatory bowel disease such as Crohn’s disease or ulcerative colitis.
  • A personal or family history of colorectal cancer or colorectal polyps.

Lifestyle factors that may contribute to an increased risk of colorectal cancer include:

  • Lack of regular physical activity.
  • A diet low in fruit and vegetables.
  • A diet high in fat
  • Overweight and obesity.
  • Frequent smoking

How Do I Tell Between Colon Cancer And Irritable Bowel Syndrome? 

SymptomsColon CancerIrritable Bowel Syndrome
Abdominal painXX
Cramping related to defecationXX
Gas and bloatingXX
Narrow stoolsX
Rectal itching

Rectal bleedingX
Blood in stool
Loss of appetiteX
Weight lossX

What Should I Do If I Suspect I Have Colon Cancer?

If the signs are clear as day, it’s best to go get it checked up at the doctor. Here’s a rundown5 of what will happen during your visit.

First, your symptoms and medical history will be reviewed, and you will be asked about the frequency and consistency of stools.

I may need a blood or stool sample to help with diagnosis. Besides this, the following tests may be carried out:

  1. An endoscopy: A thin tube with a light and camera will be attached down the throat and into the digestive tract to look for issues.
  2. A colonoscopy: A thin tube with a light and camera will be attached into the rectum to check for problems along the colon.
  3. Imaging tests: These include X-rays, CT scans, and ultrasounds. This can help me check the internal organs for problems.
  4. Fecal immunochemical testing: This is a noninvasive screening test for colon disease, where your stool will be collected and tested.


  1. National Registry of Diseases Office. (2021, March 31). Singapore Cancer Registry Annual Report 2018.
  3. Centers For Disease Control And Prevention. (2021, February 8). What Are the Risk Factors for Colorectal Cancer? Colorectal (Colon) Cancer. Retrieved December 13, 2021, from
  4. Myhre, J., & Sifris, D. (2021, June 1). Colon Cancer and Poop: Signs to Watch Out For. Verywell Health. Retrieved December 13, 2021, from
  5. Kandola, A. (2018, October 26). What can cause a change in bowel habits? Medical News Today. Retrieved December 13, 2021, from

This article was written and medically reviewed by Dr. Ganesh Ramalingam, M.D.