Colorectal Cancer Singapore

Colorectal Cancer Singapore

Colorectal cancer is the most common cancer in men in Singapore and the second most common in women. Around 2,600 new cases are diagnosed every year — roughly five people every day.

Most of them did not know anything was wrong.

Quick Facts

Why Colorectal Cancer Matters in Singapore

Colorectal cancer is not a disease of old age alone. It is Singapore’s most significant gastrointestinal cancer by volume, and the epidemiology is shifting in a direction that concerns every clinician in this field.

Colorectal cancer has historically been associated with adults over 50. Screening programmes targeting this age group have successfully reduced incidence and mortality in older adults over the past two decades. But a different trend has been emerging in parallel.

A 2025 study published in JMIR Public Health and Surveillance — analysing 53,044 colorectal cancer cases from the Singapore Cancer Registry between 1968 and 2019 — found that early-onset colorectal cancer (diagnosed in adults aged 20–49) has been rising steadily. The age-specific incidence rate approximately doubled from 5 per 100,000 population in 1968 to 10 per 100,000 in 2019. The increase has been most pronounced for rectal cancer, rising at 1.5% annually among younger men. Among ethnic groups, Malays experienced the most significant increase in both colon and rectal cancer incidence.

Crucially, patients diagnosed under 50 are more likely to present at an advanced stage — precisely because neither they nor their doctors are looking for it at that age.

This is why symptoms in younger patients cannot be attributed to age alone.

The Prevention Window: What Makes Colorectal Cancer Different

Most cancers do not announce themselves before they develop. Colorectal cancer is different.

The majority of colorectal cancers do not arise de novo. They develop from polyps — small, usually benign growths in the lining of the colon or rectum — through a well-documented process called the adenoma-to-carcinoma sequence. A polyp forms. Over time — typically five to ten years — a small proportion of polyps accumulate genetic mutations and progress to cancer.

This progression is slow enough that it is interruptable.

A colonoscopy identifies polyps while they are still benign and removes them during the same procedure. The cancer never develops. This is not early detection — it is prevention. It is why colonoscopy is described as both a diagnostic and a preventive procedure, and why it is the gold standard for colorectal cancer screening.

The implication for you: if you are in the age range for screening, or if you have symptoms, every month spent waiting is a month of that window unused.

Symptoms of Colorectal Cancer

Colorectal cancer is often asymptomatic in its early stages. The following symptoms warrant assessment by a colorectal surgeon, particularly if they are persistent or new:

Blood in the stool — may appear as bright red blood on toilet paper, blood on the surface of stools, or dark tarry stools indicating bleeding higher in the colon. Many patients assume rectal bleeding is haemorrhoids. While haemorrhoids are common, persistent or recurrent bleeding requires proper evaluation to exclude more serious causes.

Persistent change in bowel habits — diarrhoea, constipation, or alternating between the two, lasting more than two to three weeks without a clear explanation.

Narrow or pencil-thin stools — a change in stool calibre can indicate a narrowing of the bowel caused by a tumour.

Feeling of incomplete bowel emptying — a persistent sensation that the bowel has not fully emptied, even immediately after a bowel movement.

Unexplained weight loss — weight loss not attributable to dietary changes or increased activity.

Persistent abdominal discomfort — cramping, bloating, or a feeling of fullness that is new and persistent.

Fatigue or iron deficiency anaemia — chronic slow bleeding from a tumour can cause anaemia without visible blood in the stool. Unexplained iron deficiency anaemia in an adult always warrants investigation of the colon.

Risk Factors

Both lifestyle and genetic factors influence colorectal cancer risk. The following are associated with increased risk:

• Age above 45 (risk increases with age, but younger adults are not exempt)
• Family history of colorectal cancer or polyps in a first-degree relative
• Personal history of colorectal polyps
• Inherited genetic syndromes — Lynch syndrome and familial adenomatous polyposis (FAP) carry significantly elevated lifetime risk and require dedicated surveillance programmes
• Inflammatory bowel disease — Crohn’s disease and ulcerative colitis both increase colorectal cancer risk with longer disease duration
• Diet high in red and processed meat, low in dietary fibre
• Obesity and physical inactivity
• Smoking
• Type 2 diabetes

Having risk factors does not mean cancer is inevitable. Many patients with multiple risk factors never develop colorectal cancer. The relevance of knowing your risk is that it informs when and how often you should be screened.

Screening Options

Screening is how colorectal cancer is caught before it causes symptoms — and in the case of polyp detection, before cancer develops at all.

Colonoscopy remains the gold standard. A flexible camera examines the entire colon and rectum under sedation. The procedure takes 20–40 minutes and is performed as a day case. Polyps found during the examination are removed immediately. Most patients return to normal activity the same day. If no polyps or other abnormalities are found, a repeat examination is typically recommended every ten years for average-risk individuals.

FIT (Faecal Immunochemical Test) is a non-invasive stool test that detects blood invisible to the naked eye, which may indicate a polyp or cancer. It does not require bowel preparation or sedation and can be performed at home. A positive FIT result requires follow-up colonoscopy. FIT needs to be repeated annually because it has lower sensitivity than colonoscopy and does not detect or remove polyps.

Diagnosis

When colorectal cancer is suspected — based on symptoms, a positive FIT, or a finding on colonoscopy — the following investigations establish the diagnosis and guide treatment planning:

Colonoscopy with biopsy: A tissue sample from any suspicious lesion is sent for histological analysis. This confirms the diagnosis.

CT scan of the chest, abdomen, and pelvis: Staging the tumour — determining whether cancer has spread to lymph nodes or distant organs — is essential for treatment planning.

MRI of the pelvis: Required for rectal cancers to assess the relationship of the tumour to the mesorectal fascia, nearby structures, and the sphincter complex. MRI determines whether neoadjuvant (pre-operative) treatment is needed before surgery.

Blood tests: Including full blood count (to assess for anaemia), liver function tests, and CEA (carcinoembryonic antigen) — a tumour marker used for baseline measurement and post-treatment surveillance.

Staging

Colorectal cancer is staged using the TNM system based on tumour depth (T), lymph node involvement (N), and distant spread (M):

Treatment Options

Treatment is determined by the stage, location, and biology of the tumour, and is best planned through multidisciplinary discussion involving surgery, oncology, and radiology.

Surgery is the primary treatment for most colorectal cancers and is potentially curative at Stages I–III. The extent of surgery depends on where the cancer is located.

For colon cancer, a hemicolectomy (removal of the affected segment of colon with surrounding lymph nodes) is performed. This is routinely done laparoscopically or robotically, with shorter recovery and smaller incisions than open surgery.

For rectal cancer, surgery is more complex due to the anatomical location deep within the pelvis. A low anterior resection (sphincter-preserving) or abdominoperineal resection (APR) is performed depending on tumour location relative to the sphincter. Most rectal cancers require pre-operative chemoradiotherapy (neoadjuvant treatment) before surgery to reduce local recurrence risk.

Robotic surgery — using the Da Vinci Xi system — is particularly advantageous for rectal cancer surgery, where the narrow pelvic space and the proximity of critical nerves make precision the defining factor in both oncological and functional outcomes. Dr Sulaiman has performed more than 100 Da Vinci Xi rectal cancer cases.

Chemotherapy is used after surgery (adjuvant) for Stage III colon cancer and selected Stage II cases, and before surgery (neoadjuvant) for most rectal cancers in combination with radiotherapy.

Targeted therapy and immunotherapy have transformed treatment options for Stage IV colorectal cancer. Patients with mismatch repair-deficient (MMR-d) tumours — a specific molecular subtype — respond particularly well to immunotherapy. Molecular testing of the tumour at diagnosis is now standard practice.

Patient Journey Timeline

When Should You See a Colorectal Surgeon?

• Blood in the stool — even if you think it is haemorrhoids
• Persistent change in bowel habits lasting more than two to three weeks
• Unexplained weight loss or fatigue
• Iron deficiency anaemia without a clear cause
• Family history of colorectal cancer or polyps
• Aged 45 and above with no prior colonoscopy
• Positive FIT test requiring follow-up

You do not need a referral. Same-day and same-week appointments are available across five clinic locations in Singapore.

Clinical information on this page reflects Dr Sulaiman’s practice and is informed by published evidence including: Singapore Cancer Registry data (2019–2023); Chen et al., “Trends in Early-Onset Colorectal Cancer in Singapore,” JMIR Public Health and Surveillance, 2025 (PMID 39725547); National Cancer Centre Singapore cancer statistics 2025/2026 reports. Screening age recommendations reflect both MOH Singapore guidelines (age 50 for average-risk adults) and American Cancer Society guidelines (age 45). This page is for informational purposes and does not constitute medical advice.