Common Warning Signs of Colorectal Cancer

Colorectal cancer is one of the most common cancers worldwide, yet many of its early warning signs are subtle and often overlooked. Paying attention to these signals can make a life-saving difference, as early detection greatly improves treatment success and long-term health outcomes.

Below, we highlight some of the most common warning signs of colorectal cancer and understand why timely medical evaluation matters.

Key Symptoms and Warning Signs

Colorectal cancer treatment is most effective when detected and managed in its early stages. Some common indicators to watch for include:

• Changes in Bowel Habits

  : Ongoing diarrhoea, constipation or alternating patterns that persist for several weeks.

• Blood in Stool

  : Bright red or dark blood may appear in or on the stool and should never be ignored.

• Persistent Abdominal Discomfort

  : Cramps, bloating, gas or pain that does not go away with time.

• Unexplained Weight Loss

  : Significant, unintentional weight loss without changes in diet or activity.

• Fatigue or Weakness

  : Constant tiredness or low energy that is not relieved by rest.

• Incomplete Bowel Evacuation

  : A recurring feeling that the bowel does not completely empty after a movement.

If any of these symptoms occur, it is important to consult a colorectal specialist promptly for proper evaluation and early management.

Risk Factors Associated with Colorectal Cancer

Certain factors increase the likelihood of developing colorectal cancer. Being aware of these can assist in early screening and preventive measures:

• Age

  : Risk increases significantly after 50 years, although younger adults can also be affected.

• Personal or Family History

  : Individuals with a history of colorectal cancer or polyps or with family members who have had these conditions should consider regular screening.

• Inflammatory Bowel Diseases

  : Conditions such as Crohn’s disease or ulcerative colitis elevate the risk.

• Lifestyle Factors

  : A diet low in fibre, obesity, lack of physical activity, smoking and excessive alcohol consumption have all been associated with an increased risk.

Early detection through screening tests like colonoscopy is crucial, as colorectal cancer often does not show symptoms in the early stages. Colonoscopy remains the primary method for diagnosing colorectal cancer in Singapore, allowing specialists to visually examine the colon, remove polyps and collect tissue samples for further analysis, thus potentially interrupting the progression to cancer.

Colorectal Screening Guidelines in Singapore

Regular screening is key to detecting colorectal issues early, often before symptoms appear. Following Singapore’s recommended guidelines can help protect your digestive health and support timely intervention when needed.

Screening Options

The two main screening methods in Singapore are the Faecal Immunochemical Test (FIT) and colonoscopy. FIT is a simple stool test that detects small amounts of hidden blood, which may indicate polyps or cancer. Colonoscopy, on the other hand, is a more comprehensive procedure that allows direct visualisation of the colon and rectum, with the ability to remove polyps during the same procedure.

When to Screen

Colorectal cancer is the most common cancer in Singapore, with male Chinese Singaporeans facing a particularly higher risk. Detecting the disease early greatly increases the chances of successful treatment and cure. To support early detection, the Ministry of Health has established clear guidelines on colorectal cancer screening.

• Average Risk Individuals

  People aged 50 and above with no family history of colorectal cancer are considered at average risk. For this group, FIT should be done once a year, or a colonoscopy every 10 years.

• High Risk Individuals

  Those with a first-degree relative (parent, sibling or child) diagnosed with colorectal cancer are at higher risk. Screening is recommended to begin at age 40, or 10 years before the age at which the family member was diagnosed—whichever comes first. Colonoscopy is the preferred method for this group.

• Very High Risk Individuals

  Individuals with inherited genetic syndromes, such as familial adenomatous polyposis (FAP) or Lynch syndrome, fall into the very high-risk category. Screening typically begins at a much younger age and is done more frequently, under the guidance of a specialist.

Our Colorectal Cancer Surgeon

Dr Ho Kok Sun is a consultant colorectal & general surgeon in Singapore. He graduated from the National University of Singapore in 1993, obtained his Master of Medicine in Surgery in 1998 and became a Fellow of the Royal College of Surgeons of Edinburgh the same year. After completing specialist training in General Surgery in 2002, he pursued a fellowship at the Cleveland Clinic Florida and has since subspecialised in colorectal surgery. His areas of clinical interest include laparoscopic colorectal surgery, therapeutic endoscopy such as colonoscopy, and the management of anal conditions.

If you are experiencing any symptoms mentioned or seeking expert advice on colorectal cancer treatment, arrange a consultation with Dr Ho Kok Sun for a comprehensive evaluation and personalised care approach.