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According to the Singapore Cancer Society, colon cancer is one of the top 3 most common types of cancer in Singapore. Approximately 1,200 new cases of colon cancer are diagnosed each year.

Research shows that male Chinese Singaporeans are mostly at an increased risk of developing this type of cancer. Therefore, it is essential to understand facts about colon cancer and what you can do to minimise your risk.

Who Should Screen for Colon Cancer In Singapore?

Ideally, you should begin screening for colon cancer as soon as you turn 50, and continue being screened regularly. In fact, you need to start screening earlier if you have a higher risk of colon cancer.

The frequency of screening will depend on your risk factors. Below are the four colorectal risk categories and when each group should begin screening.

1. Average risk group

You are considered an average risk individual if you are generally asymptomatic or come from a family with no history of colon cancer. If your family has had a case of this type of cancer, it must be limited to non-first degree relatives. Screening is recommended to begin at the age of 50 years old if you fall in this category.

2. High-risk group

You are at high risk of developing colon cancer if one of your first-degree relatives aged 60 years or younger has been diagnosed with it. Your risk increases if more than one of your first-degree relatives has been diagnosed.

In this case, you should begin screening at the age of 40 years or ten years prior to the youngest case in your family; whichever is earlier. So, if the youngest case in your family was diagnosed at 45 years, you should begin screening at 35 years.

You are also considered higher risk if you have a medical history of colorectal polyps. In this case, you need to start screening one to three years after polypectomy.

A medical history of colorectal malignancy or ovarian cancer is another high-risk factor you should be aware of. If you fall into this category, consider starting your screening immediately after resection.

3. Very high-risk group

You fall in this group if you have a family history of familial adenomatous polyposis or hereditary non-polyposis colon cancer. You are also at very high risk if you have inflammatory bowel disease.

If you have a family history of familial adenomatous polyposis, you should start screening at 10-15 years of age.

However, if you have a family history of hereditary non-polyposis colon cancer, your screening should start when you are between 20 to 25 years old.

How to Screen for Colon Cancer?

There are different screening tests for colon cancer. Here is a quick summary of the different screening options:

Faecal occult blood tests (FOBT)

Immunochemical FOBT is used to check for blood in your stool which can be a sign of polyps or cancer. A positive test means blood was detected in your stool and will lead to further examination to determine the cause.

Sometimes, the presence of blood in your stool can be caused by other things. Since polyps don’t bleed continuously, the test must be performed on different stool samples at different times of the year.

Unlike some other tests, FOBT can be conducted in the privacy of your home, and no dietary or drug restrictions are required before the test.

Colonoscopy

During a colonoscopy, a relatively long and flexible tube is carefully inserted into your rectum. A tiny video camera at the tip of the tube allows your doctor to examine the entire length of your colon and rectum to detect any abnormalities.

The entire process takes approximately half to an hour and is repeated every ten years if your doctor doesn’t detect any abnormalities, and you don’t have an increased risk factor for colon cancer.

Though there is the need for sedation and full bowel preparation, a colonoscopy is highly accurate and recommended for high-risk individuals.

During bowel preparation, your doctor may stop some oral medications for days and put you on a low fibre diet for at least three days.

Some of the foods you need to avoid during this period include vegetable soup, cereals, grains, fruits, and vegetables.

Virtual colonoscopy / CT colonography

Virtual colonoscopy is a relatively new radiologic technique that generates clear images of the colon and rectal wall.

Like colonoscopy, bowel preparation is still needed but it doesn’t require sedation. However, small lesions may be missed and interventions such as biopsies and polypectomy cannot be performed.

To create clear images, a slightly smaller tube is carefully inserted into your colon to fill it with air. The process takes approximately ten minutes and is usually repeated every five years if nothing is detected.

Sigmoidoscopy

Like colonoscopy, your doctor may recommend sigmoidoscopy to check for polyps or any other signs of cancer. However, during sigmoidoscopy, the doctor will mainly examine the rectum and left-sided colon.

Sigmoidoscopy only takes 10-20 minutes to complete. It requires laxatives given through the anus before the test. If evidence of cancer or polyps are detected, your doctor will still recommend a colonoscopy to examine the entire colon.

Barium enema

This is another alternative to colonoscopy suitable for large bowel evaluation. Bowel preparation is needed, and your doctor may still recommend colonoscopy to rule out suspicious lesions detected on your enema. The process is generally simple and takes approximately 30 minutes to complete.

How Often Should You Go for Screening

The waiting period between screenings will depend on the results of your first screening and the method used.

Generally, FOBT is done every year for normal results, while sigmoidoscopy should be done every 5 years if combined with a faecal immunochemical test (FIT) done every year.

A colonoscopy is recommended once every ten years for people with no increased risk of colon cancer. CT colonography/virtual colonoscopy should be done every five years.

Keep in mind that you may be required to undergo regular screening if you are at an increased risk of developing colon cancer. Your doctor will assess your condition and provide you with an ideal screening schedule.

Conclusion

Colon cancer is common, not just in Singapore but globally. Fortunately, screening and early treatment reduce cancer-related deaths significantly. Typically, screening for colon cancer should start at the age of 50.

But if you are at an increased risk of developing colon cancer, you need to start screening earlier based on the recommendations outlined above. The frequency of screening will depend on your condition and the screening option you choose to use.

Have you or someone you know been diagnosed with colon cancer?  If so, one of the first things that the doctor will want to determine is the stage of the cancer.

Staging is a unique way of describing the local extent of the cancer and how far it has spread to other organs in the body. This process is critical because it helps the doctor determine the best treatment option.

Different diagnostic tests are used to establish the stage of cancer. There are also different stage descriptions for various types of cancer. In this article, we focus on colon cancer staging.

Staging of Colon Cancer

Colon cancer is staged based on the TNM staging system created by the American Joint Committee on Cancer. Your doctor will use the results from the diagnostic tests and scans performed to answer the following questions:

Tumour (T)

How far has the primary tumour grown into the wall of the colon or rectum?

Node (N)

Has the tumour spread to the neighbouring lymph nodes? If so, where and how much has it spread?

Metastasis (M)

Has the cancer tumour spread from your colon to other body parts such as the liver and lungs?  If so, where and how much has it spread?

Colon Cancer Stage Grouping

The five stages of colon cancer are as follows:

Stage 0

Stage 0 means your cancer has not grown beyond the innermost layer (mucosa) of the colon or rectum.

Stage 1

Stage 1 indicates that the cancer has extended beyond the innermost colon layer  (mucosa) to the next layers, referred to as submucosa or muscularis propria. However, it has not started to spread to the regional lymph nodes.

Stage 2

In stage 2, the cancer is a little bit advanced and has grown beyond both the mucosa and submucosa. Stage 2 can be classified into three distinct sub-stages, namely:

• 2A:  The cancer cells have not spread to regional lymph nodes or any other nearby tissue. It has only reached the outer layer of your colon.
• 2B: The cancer cells have not spread to the lymph nodes, but they have grown through the outer colon layer and to the visceral peritoneum (the membrane that holds the abdominal organs in place).
• 2C: The cancer cells have not spread to the lymph nodes but have grown to nearby body organs.

Stage 3

Stage 3 colon cancer can be classified as 3A, 3B, and 3C.

• 3A means the primary tumour has grown through the muscular layers of your colon into the nearby lymph nodes. However, it has not spread to distant body organs.
• 3B means the primary tumour has started to penetrate the visceral peritoneum. The cancer cells can be found in one to three lymph nodes and have not started to invade nearby body organs. It can also mean the tumour has not penetrated through the outer colon layers but can be found in at least four lymph nodes.
• 3C means the primary tumour has grown beyond the muscular layers, and cancer cells can be found in at least four nearby lymph nodes. Alternatively, the cancer has grown through the wall and invade nearby tissue or organ and has spread to at least one lymph node.

Stage 4

Stage 4 colon cancer is divided into two sub-stages, namely:

• 4A: This stage means the cancer cells have spread to at least one distant body organ such as the liver or distant set of lymph nodes.
• 4B: The cancer cells have spread to more than two distant body or distant set of lymph nodes.
• 4C: The cancer cells have spread to the distant parts of the peritoneum (the lining of the abdominal cavity)

Low-Grade vs High-Grade

In addition to conventional staging, colon cancer can also be classified as either low-grade or high-grade.

Typically, when a pathologist examines cancer cells, they assign a number that ranges between one and four depending on how healthy the cells look.

The higher the grade, the more abnormal the cells look.  In most cases, low-grade cancer grows slower than high-grade cancer. People who have low-grade cancer stand a better chance of recovery.

Tests to Diagnose and Stage Colon Cancer

Doctors may recommend a wide range of tests to diagnose colon cancer.  They also perform different tests to determine whether it has spread to other parts of the body. The following tests may be performed to diagnose colon cancer.

Blood tests

Although a blood test cannot reveal if you have colon cancer, your doctor will be looking for clues about your overall health.  He/she may also test your blood for chemical substances produced by colon cancer, such as carcinoembryonic antigens.

Blood tests will also measure the different types of cells in your blood. The blood cell count can reveal if you have anaemia because some people with colon cancer become anaemic as a result of the tumour bleeding.

Diagnostic colonoscopy

A diagnostic colonoscopy will only be done if you show symptoms or if something abnormal was found in another test.

A colonoscopy allows your doctor to examine the entire length of your colon or rectum to establish if there are any abnormalities.

The screening is done using a thin, flexible and lighted tube with a powerful video camera attached on one end.  The tube is usually inserted through the anus into your colon and rectum.

Biopsy

If your doctor suspects the presence of cancer cells during colonoscopy, he/she will recommend a biopsy. In a biopsy, a small piece of the colon/rectum tissue is extracted for examination.

A biopsy is the only way to make an accurate diagnosis of colon cancer.

Imaging tests

Imaging tests such as computed tomography scan, ultrasound, magnetic resonance imaging (MRI) scan or positron emission tomography (PET) scan use x-rays, magnetic fields or radioactive substances to generate clear images of internal body organs to help the doctor look for suspicious cancer growths or determine how far cancer has spread.

Colon Cancer Treatment by Stage

After examining your cancer and determining its stage, the doctor will recommend an appropriate course of treatment.

For stage 0 colon cancer, a polypectomy may be performed to get rid of all malignant cells. If the cells have affected a much larger area, the doctor may perform a resection (a minor and minimally invasive surgery).

For stage 1 colon cancer, surgery is usually performed to remove the affected cells. The surgery is referred to as colectomy and involves rejoining the healthy parts of your rectum or colon.

Stage 2 colon cancer is still treated with surgery that gets rid of the affected areas. The surgery may be combined with chemotherapy to yield better results.

The treatment for all categories of stage 3 colon cancer involves surgery to remove the affected areas. Surgery is combined with chemotherapy, but your doctor may recommend radiation treatment if surgery is not suitable.

Lastly, stage 4 colon cancer is treated by various treatment options. Surgery may be performed to remove the primary tumour or small affected areas in distal body organ. Chemotherapy, immunotherapy, targeted therapy or radiation may be given based on patient’s condition.

Conclusion

Diagnosing colon cancer at the earliest stages offers you the greatest chance for recovery. Doctors generally recommend that individuals with an average risk of colon cancer begin screening at the age of 50.

If you are diagnosed with colon cancer, your doctor will perform several tests to determine its stage and recommend appropriate treatment options.

It is crucial to understand that many factors will determine your survival rate, including your cancer stage, overall health, age, and how you respond to treatment.

Overview

The colon is at the final portion of the digestive tract. Colorectal cancer is the second-most commonly diagnosed cancer among women after breast cancer. In Singapore, approximately one in seven women diagnosed with cancer between 2011 and 2015 had colorectal cancer.

Even though colon cancer can happen at any age, it commonly affects women in older age groups.

Colon cancer originates from polyps forming inside of the colon. Polyps are small, noncancerous (benign) growths that can become cancerous (malignant) over time.

What Are the Symptoms in Women?

Colon cancer is generally asymptomatic in its early stages. When the symptoms start to show up, chances of treatment is dependent on the local extent and stage of the cancer.

The symptoms of colon cancer include:

1. A change in your bowel routines, frequency or consistency of stools
2. You notice blood in your stools and rectal bleeding
3. Abdominal discomforts, such as cramps and pain
4. A sensation that you have not completely emptied your bowels
5. Fatigue, lethargy or feeling weak
6. Unexplained weight loss

Colon Cancer Symptoms vs Menstruation-Related Symptoms

It is common for women to confuse  symptoms of colon cancer with that of their menstrual cycle, as symptoms such as feeling weak and tired may be similar.

Oftentimes,  abdominal discomforts are mistaken for menstrual cramps. Thus, you should speak to your doctor if your lethargy is persistent and not in line with your menstrual cycle. If the symptoms feel different from what you regularly experience during your menstrual cycle, it is advisable to seek medical advice from a colorectal surgeon.

What Are the Risk Factors?

There are many lifestyle factors associated with colon cancer. However, risk factors do not necessarily mean that you will or will not get cancer. There are cases whereby people get cancer with no known factors. Some of the risks associated with colon cancer include:

• Overweight or obesity – Weight is commonly linked to cancer. Being overweight increases your risk of developing and dying from colon cancer. It affects both females and males, but studies show that the link between being overweight and developing colon cancer is stronger in males. Maintaining a healthier weight range would lower your risk of getting colon cancer.
• Lack of regular exercise – Not getting enough exercise increases your risk of colon cancer. It is vital to participate regularly in moderate to vigorous exercise to help lower your risk of colon cancer.
• Unhealthy diets – Having a diet with high intake of red meats (beef, pork, or lamb) and processed meats (hotdogs and luncheon meat) increases your chances of getting colon cancer. Cooking meats at high temperatures, such as frying and grilling, creates chemicals that might increase cancer risk when they are consumed. Low levels of vitamin D intake also increases the chances of getting colon cancer. Having a healthy and balanced diet consisting of fruits and vegetables would be helpful to decrease the chances of developing colon cancer. You should have sufficient protein intake but avoid too much red, processed meat, and sugary drinks.
• Smoking – Even though smoking is a common cause of lung cancer, it also causes other cancers. If you are a heavy smoker, you are more likely to develop colon cancer than individuals who do not smoke.
• High alcohol intake – Moderate to high alcohol intake increases the risk of colon cancer. Individuals who drink alcohol regularly have a higher risk of developing colon cancer. It is advisable not to drink too much alcohol, but if you do, you should limit it to no more than 2 standard drinks per day.

How Is Colon Cancer Diagnosed?

Diagnosis of the individual can be conducted through colonoscopy. If any abnormalities are observed, the tissue sample of the tumour will be removed by a biopsy and sent for laboratory analysis.

Should there be cancer cells present, your doctor will conduct further tests to determine the cancer stage. There are a few stages of colon cancer.

• Stage 0: This is called cancer in situ. The cancer cells are only in the innermost lining of colon and rectum. The cancer cells have yet to develop nor spread but only present in the innermost lining of the colon or rectum.
• Stage 1: The tumour is starting to spread through the inner lining of the colon.
• Stage 2: The tumour begins to grow deeper through the colon’s wall and may invade nearby structures.
• Stage 3: The tumour spreads to nearby lymph nodes.
• Stage 4: The tumour develops further, and cancer has spread to other parts of the body.

What Are the Treatment Options?

• Surgery – Traditional open surgery or laparoscopy can remove the tumour with its surrounding.
• Chemotherapy – This treatment uses drugs that enter the bloodstream and travel to the cancer cells to shrink or destroy the cancer cells.
• Targeted cancer therapy – When colon cancer has spread to all other parts of the body, drugs or substances will be induced to target specific molecules involved in tumour growth, to stop  or reduce  the spread of colon cancer.
• Radiation therapy – High energy rays destroy the cancer cells in affected parts of the body.

Conclusion

Colon cancer is one of the most preventable and curable cancers if you go for health screening regularly. During early diagnosis, the cancer cells are still confined to the large intestine and are highly treatable. Removing precancerous cells will reduce your chances of developing advanced stages of colon cancer.

Treatment is most effective at the early stages, and the survival rates for females are approximately 90% when treated early.

What Is an Anal Fistula?

An anal fistula is a small passage that forms between the anal canal or lower part of the rectum and skin surrounding the anus, due to a bacterial infection in the rectum. Such infection leads to a collection of abscesses (pus) in the surrounding rectal tissue. As the pus drains out, it leaves behind a tunnel (fistula).

The anus is made up of small glands that excrete mucus. When these glands get clogged, an infection may set in, leading to the formation of abscesses. About half of these abscesses (bacteria) may increase in size, forming a track that leads to the skin around the anus.

Causes

Anal abscesses and clogged glands are the leading causes of anal fistula. Other possible causes of an anal fistula include:

• Inflammatory bowel disease
• Diverticulitis (colon infection, especially in older people)
• Crohn’s disease (intestinal inflammation)
• Cancer and its treatment procedures like radiation therapy
• Sexually transmitted diseases
• Tuberculosis

Signs and Symptoms

Anal fistula causes unpleasant and uncomfortable symptoms. These include skin irritation that keeps getting worse with time. Other common symptoms include:

• Feeling itchy around the anus as a result of skin irritation
• Smelly discharge (abscess) from an opening near the anus
• Persistent throbbing pain that gets worse when walking, sitting or coughing
• Rectal bleeding and pain when passing faeces
• Chills, fever and general body weakness

Diagnosis and Treatment

Diagnosis

Your doctor may perform several tests to diagnose an anal fistula, but the first step is the physical examination. Your colorectal surgeon will examine the anal area for any physical opening or skin inflammation.

In the case of a physical opening, your doctor will perform further analysis to determine the depth and direction of the tract (fistula).

However, some fistulas may need additional tests. These include:

• Anoscopy – A special tube with a video camera and source of light at the tip is inserted into the rectum through the anus. This enables the doctor to check for any abnormalities in the rectum and anal canal.
• MRI or Ultrasound – This is a non-invasive procedure that helps the doctor get a better view of the fistula.

Diagnostic methods used to rule out other disorders such as cancer or inflammatory bowel disease include:

• Flexible sigmoidoscopy. A thin, flexible tube with a lighted camera inside the tip allows doctors to view the lining of the rectum and sigmoid colon as a magnified image on a television screen.
• Colonoscopy. Similar to sigmoidoscopy, but with the ability to examine the entire colon or large intestine.

Treatment

Surgery is the most effective ways to treat fistula. Your colorectal surgeon will perform the surgery, balancing between clearing the fistula and keeping the patient’s sphincter muscles intact. Any damage to the sphincter muscles may lead to bowel incontinence. Common treatments for fistula include:

Fistulotomy – This treatment works best for fistulas that have few sphincter muscles involved. The surgeon will cut open the skin and muscle around the fistula and convert the tunnel into a groove. This ensures the tunnel heals from the bottom up.

Seton Procedure – Your doctor places a surgical thread through the fistula and ties it to create a continuous ring between the outside and the inner openings of the tunnel. This thread remains for a couple of weeks as it helps with the drainage of abscess, thus preventing further infection. Once the fistula heals, the surgeon will perform a further procedure to close the fistula’s opening.

Fibrin Glue – The doctor injects a combination of fibrinogen, calcium and thrombin to form a clot within the fistula, allowing healthy tissue development to fill up the tunnel.

Endorectal Advancement flap – Your surgeon takes a healthy flap of your bowel lining and covers the fistula’s internal opening. As the healthy flap heals up, the tunnel drains the abscess and healing begins.

Fistula Plug – Your surgeon uses animal tissue to create a plug that blocks the fistula’s internal opening. This infection-resistant plug spurs development of normal tissue that eventually fills up the fistula tract.

The LIFT procedure – Your surgeon will open up the skin around the anus, dissect between the anal sphincters, locate the tract and tie off the fistula.

Your colorectal surgeon will discuss these options with you before the surgery. This will be based on their judgment regarding the severity of the condition and patient’s preferences.

Colorectal surgery is generally straightforward, and you may not need to stay in the hospital for more than a day. An experienced colorectal surgeon will ensure the process is seamless to avoid recurring cases of abscesses and tampering of the sphincter muscles.

Conclusion

Anal fistula is an invasive condition with uncomfortable signs and symptoms. Fortunately, the condition is highly treatable. However, you can reduce the chances of suffering from anal fistula by keeping your stools soft, avoiding constipation and emptying your bowels as soon as you feel the urge. Drinking lots of fluids also helps clear your digestive system and prevent the build-up of bacteria that may end up forming abscesses in the rectum.

What Is A Colonoscopy?

A colonoscopy is a diagnostic process that helps doctors examine the rectum and colon for any abnormalities and disease. During this examination, the doctor uses a long and flexible tube with a built-in camera lens at the tip. The tube, called a colonoscope, measures half an inch in diameter, is carefully inserted through the anus into the rectum and manoeuvres through to the colon.

During this procedure, the doctor may remove any form of abnormal tissue (polyps) using the colonoscope. The tissue samples can then be taken for further examination through a biopsy.

Why Is It Important?

Colorectal cancer is one of the most common types of cancer in Singapore. Research shows that about 1,200 new cases are diagnosed every year. It is also one of the top three leading causes of cancer deaths in Singapore for men and women. Male Chinese Singaporeans are particularly at a higher risk of developing colon and rectal cancer, thus it is important for early diagnosis and treatment.

Regular screening for colon cancer helps detect early signs of adenomatous polyps that may advance to colorectal cancer. Adenomatous polyps go through multiple gene mutations for about 5 to 10 years before finally manifesting in the form of colorectal cancer.

Adenomatous polyps are asymptomatic, making it challenging to detect them unless the patient goes through a colonoscopy. Research shows about 25 per cent of Singaporeans above 50 years old have these polyps, and it is more common as their age increases.

A colonoscopy allows doctors to detect a premalignant phase of colorectal cancer called adenoma. The phase can be treated before it progresses to advanced stages of colorectal cancer which are more serious and chances of treatment are lower. Therefore it is important for individuals to schedule regular screenings to rule out any presence of polyps or early stages of colorectal cancer.

Who Should Undergo Colonoscopy?

In Singapore, screening is advisable for the following groups with higher risks of colorectal cancer:

• Aged 50 years and above
• Have a family history of colon and rectal cancer (including those who are under 50 years old)
• People with inflammatory bowel disease
• People with lifestyle risk factors such as obesity, smoking
• People experiencing symptoms of colorectal cancer

Individuals should also be aware of the symptoms of colorectal cancer, which includes:

• Change in bowel habits
• Rectal bleeding
• Blood or mucous in the stools
• Sudden weight loss
• Abdominal pain
• Iron-deficiency anaemia

What to Expect During a Colonoscopy?

Your doctor will usually perform the procedure under sedation. During a colonoscopy, the patient lies on their side but may be asked to adjust their position to let the doctor move the colonoscope through the colon, with minimal discomfort. In most cases, a colonoscopy will lead to an accurate diagnosis of conditions in the colon.

If the doctor finds no polyps, the process should take around 20 to 30 minutes. However, if it involves the removal of polyps, this may take an hour or more depending on the size and number of polyps found.

Prior to the process, your doctor will need to know if you are under any form of blood-thinning medications. This is because the procedure can sometimes lead to bleeding if the patient is under any blood-thinning medications like:

• Aspirin
• Warfarin
• Rivaroxaban
• Plavix

Bowel preparation and cleansing of faecal matter is also important before a colonoscopy exam. This enables the doctor to have a better and clearer view of your colon. For better results, you will be instructed to take the following steps:

• Stick to a low fibre diet a few days before the exam
• Take a strong laxative 12 hours before your colonoscopy appointment
• If you must eat after taking the laxative, go for a diet with only clear liquids

A colonoscopy is generally a safe procedure. However, rare cases of bleeding, reaction to the sedative or perforation of the colon may happen. After the procedure, the doctor will move you to an observation ward, and you will remain under observation for about one hour or more as the sedative wears off.

You should be ready for discharge within one to two hours. Your doctor will deliver and explain the results of your colonoscopy before discharge.  However, in cases where a biopsy is necessary, you might need to return to review the histology report, where the doctor will disclose and explain the biopsy results.

Conclusion

Although colorectal cancer is common among the older generation, this does not mean younger individuals are spared.  It can happen at any age, depending on your lifestyle as well as risk factors.

This emphasises the need to go for screening at the earliest opportunity. It is important to note that the early stages of colorectal cancer usually do not present any symptoms, and by the time there are symptoms, it may be too late for cure.

Screening and diagnosis at early stages increase the likelihood of the treatment leading to full recovery. A colonoscopy is a painless and quick process, since the patient is under sedation. If you have higher risks or are experiencing symptoms of colorectal cancer, it is advisable to go for a colonoscopy as a screening method for prevention and early diagnosis of colorectal cancer.