Colorectal Cancer

Colorectal cancer is the #1 cancer in Singapore.

A large majority of cases can be prevented with early detection through a Colonoscopy

20+ years of experience

5000+ scopes performed

Fellowship-trained colorectal surgeon

Medisave & Insurance Claimable

Colorectal cancer refers to cancer that begins in the colon (large intestine) or rectum, which together forms the final part of the digestive tract. It typically starts as small, benign growths called polyps that may develop into cancer over time if left untreated.

In Singapore, colorectal cancer is the most common cancer among men, and the second most common among women. It accounts for a significant number of cancer-related deaths each year, making early detection, and timely treatment essential.

What are the types of Colorectal Cancer?

Some of the most common types of colorectal cancer include:

Adenocarcinoma – adenocarcinoma accounts for over 90% of colorectal cancers. It arises from the cells lining the inside of the colon or rectum.

Carcinoid tumours – carcinoid tumours originate from hormone-producing cells in the intestine.
Gastrointestinal stromal tumours (GISTs) – GISTs are rare tumours that begin in the muscle layer of the colon.
Lymphoma – lymphoma is a cancer of the immune cells, which can occur in the colon or rectum.
Squamous cell carcinoma – squamous cell carcinoma is a rare type found more often in the rectum than in the colon.

What causes Colorectal Cancer?

Colorectal cancer usually develops from genetic mutations in the cells of the colon or rectum. While the exact cause may not always be clear, several factors increase the risk, including:

Ageing – as we age, cells accumulate more genetic mutations, and the body's ability to repair DNA damage declines, increasing cancer risk.

A diet high in red or processed meats – red or processed meat may contain carcinogenic compounds formed during processing or high-temperature cooking, which can damage the lining of the colon over time.
A sedentary lifestyle – lack of physical activity can slow digestion, and increase inflammation, both of which are linked to a higher risk of colorectal cancer.
Family history of colorectal cancer or inherited syndromes – certain genetic mutations passed down through families can significantly raise the lifetime risk of developing colorectal cancer.
Inflammatory bowel diseases – chronic inflammation in the colon increases cell turnover and the risk of abnormal cell growth that may lead to cancer.
Smoking and excessive alcohol intake – smoking introduces harmful chemicals into the body, while alcohol can irritate the bowel lining. In fact, both can contribute to genetic mutations that trigger cancer.

Typically, colorectal cancer may not cause symptoms in its early stages. But as it progresses, patients may notice:

A change in bowel habits (diarrhoea, constipation, or narrow stools).
A feeling that the bowel does not empty completely.
Abdominal discomfort, cramping or bloating.
Blood in the stool or rectal bleeding.
Fatigue or weakness.
Unexplained weight loss.

Who is at risk of Colorectal Cancer?

While colorectal cancer can affect anyone, several risk factors make certain individuals more susceptible to developing this condition. This includes:

Age — the risk of colorectal cancer increases significantly after the age of 50. As the population ages, the likelihood of abnormal cell changes in the colon or rectum rises due to the cumulative effect of environmental and genetic factors.

Family history or inherited syndromes — having close relatives with colorectal cancer or hereditary conditions like Familial Adenomatous Polyposis (FAP) or Lynch syndrome greatly increases lifetime risk. These genetic syndromes often lead to earlier, and more aggressive disease.
Chronic inflammation — individuals with inflammatory bowel diseases (IBDs) such as Crohn’s disease or ulcerative colitis experience ongoing inflammation in the colon, which increases cell turnover, and the risk of cancer development.
Sedentary lifestyles — physical inactivity can slow down bowel movements, and increase inflammation, both of which contribute to a higher likelihood of colorectal cell changes over time.
Smoking and alcohol use — tobacco smoke, and alcohol can damage the DNA in colon cells, and lead to the formation of cancerous growths. In fact, long-term use greatly compounds the risk.
Unhealthy diets — diets high in red or processed meats, and low in fibre are associated with higher risk. These foods can produce carcinogenic by-products during digestion, especially when consumed frequently or prepared using high-heat methods.

If you are experiencing the symptoms,

consult a medical professional immediately.

Schedule an appointment with Dr Aaron Poh.

book an appointment

How is Colorectal Cancer diagnosed?

Colorectal cancer is diagnosed through a combination of clinical evaluation, diagnostic imaging, and laboratory testing. There is no single test that can confirm the condition, so diagnosis relies on a structured process aimed at detecting cancer early, assessing its extent, and guiding treatment planning.

This includes:

Medical history and symptom review — Dr Aaron Poh (link to doctor’s page) will begin by asking about changes in bowel habits, rectal bleeding, abdominal discomfort, weight loss or fatigue. He will also inquire about your dietary habits, family history of colorectal cancer, and any previous colon screening results.
Physical examination — a physical assessment may include an abdominal, and rectal examination to check for palpable masses or signs of local disease. This helps guide further diagnostic testing.
Blood tests — a tumour marker known as carcinoembryonic antigen (CEA) may be elevated in colorectal cancer. Though not used for diagnosis alone, CEA levels help monitor treatment response, and detect recurrence.
Colonoscopy — a colonoscopy is the go-to diagnostic measure for detecting colorectal cancer. A thin, flexible tube with a camera is inserted into the rectum to visually inspect the colon. Any suspicious growths, such as polyps (link to colonic / rectal polyps page) or tumours, can be biopsied during the same procedure for laboratory analysis.
Imaging scans — imaging tests, such as computed tomography (CT) scan, or magnetic resonance imaging (MRI) are essential for staging colorectal cancer. These scans assess whether the cancer has spread to nearby lymph nodes, the liver, lungs or other organs.

What are the stages of Colorectal Cancer?

Colorectal cancer is classified into stages based on how far the cancer has grown, and whether it has spread. Staging plays a crucial role in deciding the most appropriate treatment, and in predicting outcomes.

Stage 0 (Carcinoma in situ) – abnormal cells are confined to the innermost lining of the colon or rectum, and have not spread. This is the earliest and most treatable stage.
Stage I – cancer has grown into the inner layers of the colon or rectum but has not spread beyond the bowel wall or to nearby lymph nodes.
Stage II – cancer has penetrated through the wall of the colon or rectum but has not reached the lymph nodes.
Stage III – cancer has spread to one or more nearby lymph nodes but not to the distant organs.
Stage IV – cancer has spread to distant parts of the body, such as the liver, lungs or other organs.

Schedule Your Appointment with Dr Aaron Poh.

How is Colorectal Cancer treated?

The treatment for colorectal cancer focuses on removing the tumour, eliminating any remaining cancer cells, and reducing the risk of recurrence. Dr. Aaron Poh offers a comprehensive, and personalised treatment plan based on the stage of cancer, tumour location, and overall health of the patient.

Some of the treatment plans that he offers are:

Surgical Intervention

Polypectomy and local excision — for very early cancers or precancerous polyps, removal may be achieved during colonoscopy without the need for open surgery.
Laparoscopic or robotic-assisted colectomy — minimally invasive surgery is performed through small incisions using a camera, and specialised instruments. This results in less pain, a shorter hospital stay, and quicker recovery.
Segmental colectomy or proctectomy — when larger tumours are present, the affected portion of the colon or rectum is surgically removed, and the healthy ends are rejoined. Lymph nodes in the area are also removed to assess cancer spread. This can be performed as a Laparoscopic or Robotic-assisted procedure.
Stoma creation — in some cases, a temporary or permanent stoma (an opening in the abdomen for waste elimination) may be required, particularly when the lower rectum is involved.

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells, and is typically recommended for:

Stage III or IV cancers.
After surgery to reduce recurrence.
Before surgery to shrink larger tumours (neoadjuvant chemotherapy).

Additionally, some common regimens include medications such as 5-fluorouracil (5-FU), oxaliplatin, and capecitabine.

Radiation Therapy

Radiation therapy is primarily used in rectal cancer, often in combination with chemotherapy. It may be given:

Before the surgery to reduce the tumour size.
After the surgery to eliminate the remaining cancer cells.
As palliative treatment in advanced cases.

Supportive and Palliative Care

When cure is not possible, palliative care focuses on improving quality of life by relieving symptoms such as pain, bowel obstruction or bleeding. This may involve a combination of surgery, radiation, and medical therapies.

Clinical Trials

Clinical trials offer access to innovative treatments not yet available in standard care. They may include new chemotherapy combinations, targeted therapies, immunotherapies or novel drug delivery systems.

Dr Aaron Poh may refer suitable patients for ongoing clinical trials in Singapore, particularly those with advanced or treatment-resistant cancer. Participation in clinical trials is entirely voluntary, and includes a thorough discussion of potential benefits, risks, and eligibility criteria.

Clinical trials can be a valuable option for:

Patients with limited response to standard therapies.
Those interested in contributing to medical research.
Individuals seeking access to innovative treatment approaches.

If you are interested, speak with Dr Poh about available trials, and whether they may be appropriate for your condition.

Summary

Colorectal cancer is one of the most treatable types of cancer when it is caught early. With timely screening, many cases can be detected before symptoms appear, and treatment at this stage is often highly effective.

Whether you are experiencing symptoms, have a family history or are simply due for a routine screening, early diagnosis can significantly improve your outcome, and reduce the need for aggressive treatments later.

Dr Aaron Poh is committed to providing personalised, compassionate care at every stage. If you have concerns or would like to schedule a screening, do not delay. Schedule a consultation with us for a detailed diagnosis and tailored treatment plan.

Frequently Asked Questions (FAQs)

Is colorectal cancer preventable?

Yes, many cases are preventable with regular screening, a healthy diet, and an active lifestyle.

How often should I go for screening?

For average-risk individuals, screening typically begins at age 50. Those with risk factors may need to start earlier. Be that as it may, it is best to speak with Dr. Aaron Poh for a personalised recommendation.

Is surgery always necessary?

Not always. For early-stage cancers or polyps, less invasive procedures may be sufficient. In other cases, surgery is part of a combined treatment approach.

What is the recovery time after colorectal surgery?

Recovery varies, but patients typically return to normal activities within 4 to 6 weeks, especially with minimally invasive techniques.

Can colorectal cancer come back after treatment?

Yes, recurrence is possible, which is why follow-up care, and monitoring are essential.

Meet Our Doctor

DR AARON POH

Dr Aaron Poh is a fully accredited General Surgeon with dual subspecialties in Colorectal Surgery and Trauma Surgery, recognised by Singapore’s Specialist Accreditation Board and Ministry of Health. He is the Medical Director of Alpine Surgical Practice, with clinics located at Mount Elizabeth Hospital, Parkway East Hospital, and Farrer Park Hospitals.

Dr Aaron Poh has extensive experience, having performed over 5,000 endoscopic procedures. He is a strong advocate for early detection through colonoscopy, particularly for individuals at risk of colorectal cancer. His expertise includes advanced endoscopic techniques such as Endoscopic Mucosal Resection (EMR) for complex polyps and colonic stenting for obstructed cancers, which help patients avoid major emergency surgery.

When surgery is required, he specialises in minimally invasive laparoscopic colorectal cancer surgery, offering patients faster recovery with less pain and scarring. In addition to cancer care, he manages a wide range of anal conditions including haemorrhoids, fistulas, fissures, and abscesses, providing comprehensive colorectal treatment.