Colorectal cancer is now the most common cancer in Singapore. It affects males and females alike. Most people diagnosed with colorectal cancer are older than 45 years of age.

Common symptoms include a change in bowel habits, such as persistent diarrhoea or constipation, or a change in the frequency of passing stools. Passing blood mixed with stools is also a suspicious sign, which always needs prompt medical attention. Other symptoms include persistent ill-defined abdominal discomfort or pain.

Dr Fu Wan Pei Cherylin, Consultant from the Department of Colorectal Surgery at Singapore General Hospital, gives detailed answers to your questions.

Question by alastairlaujh

Hi Dr Fu My Grandparents had colon cancer. Aunt and Dad as well. How often should i go for a colonoscopy? Thank you

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

You certainly have a strong family history of colorectal cancer, including that of a first degree relative. Are your grandparents and aunt who had colon cancer also from your paternal side of the family?

As you would be considered as having an increased risk of colorectal cancer you should start having your first colonoscopy 10 years earlier than the youngest age of onset of colorectal cancer in the family. Eg. If the earliest age at which one of your family members developed colon cancer was 45, then you should have your first colonoscopy when you are 35.

If your colonoscopy is normal you should consider screening colonoscopy every 3 to 5 years thereafter, provided each colonoscopy is normal. The rest of your family members of the affected side of the family should also be encouraged to go for screening colonoscopy accordingly.

Question by [email protected]

Dear Doctor, I have pain after passing stool. I tested my blood but noithing trace of blood were found. The soreness/pain is more after passing urine. Doctor said it is piles after physical examination. Pls advise if I should go for a detailed colonoscopy exam for more detailed check and what is the medication for piles and if it is completely curable. Doctor advised xyloproct suppositoreis and cream.

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

Pain after passing stools are most commonly due to anal fissures (small tears of the anal skin usually at the anal verge) or due to external haemorrhoids (also known as external piles) that have become swollen or have developed a blood clot within (thrombosis). External piles usually do not bleed overtly even though they may be painful, as opposed to internal piles which may bleed without causing any pain at all. Your doctor should be able to determine if the cause of the anal pain is an anal fissure or piles after examining you.

Treatment for anal fissures usually involves application of a topical medication (Glyceryl Trinitrate cream) to relax the anal sphincter muscles. Treatment for piles ranges from oral medications (Diosmin/ hesperidin) to surgery (haemorrhoidectomy) depending on the severity and symptoms of piles. External piles may reduce in size with medications and creams but to be completely “cured”, they would need to be surgically removed. Surgical removal is considered only if you are symptomatic from your piles. Piles that are not bothersome and not causing any symptoms can be left alone. They do not turn cancerous or affect your health.

Certainly if you have any other symptoms such as abdominal pain or discomfort or a change in bowel habit, you should consider having a colonoscopy to ensure that there is no underlying problem with the colon or rectum.

Question by janet chu

I first stated with a discomfort on the right sight of my stomach. Gone through ultra scan, scope, colonscopy and CT Scan and doctor said all tests are fine. Doctor diagnose that it might be due to stress. However, this 1 year, I find my bowel pattern has changed. My stool is dark chocolate colored. Tends to be sticky and very smelly. I'm a female, aged 44 this year. I did my body checkup last April including stool sample and result was well. Could you advise if there is some kind of problem with the stinky stool.

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

Stool smell, consistency and colour varies from person to person and may be related to the type of food you eat and the bacterial flora in your gut, among other things. Dark chocolate coloured stool is pretty normal so you should not be overly concerned. If the scans and the colonoscopy that were all done were normal, it means that there is probably nothing abnormal with the structure of your large intestine. Instead, your symptoms may be related to disordered bowel function such as irritable bowel syndrome. Avoiding foods that cause gas production such as beans and legumes as well as taking probiotics may help to improve the stool consistency and smell.

Question by myskinnyguy

If there a thin peel like material or seed-like material in the stool, is this normal?

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

Yes, it is very common to see bits of vegetable or fibre matter in the stool as the human body does not produce enzymes to break down fibre. Hence undigested fibre, including seeds and husks get passed out in the stool unchanged.

Question by peter

Hi, I did my colon screening after 1 of the 2 samples kits was found positive during routine check back in May 2012. A flat sessile polyp at proximal descending colon about 3mm dia.-- removed by hot biopsy. May I ask when should I go for the next colon screening again. Thanks n have a good day ahead. Peter

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

We would need to know the histology of the polyp removed to advise you regarding the frequency of colonoscopic surveillance. Colonoscopic surveillance guidelines vary from country to country.

Assuming you have no other risks factors such as a personal history or family history of colorectal cancer and that the bowel preparation was good – If the polyp was a hyperplastic polyp, repeat colonoscopy every 5 to 10 years would usually suffice. If you had a small 3mm polyp that was an adenoma with low grade dysplasia, you should have a repeat colonoscopy in about 3 years’ time. However, if it was a polyp with high-grade dysplasia that was completely removed, you would need a repeat colonoscopy earlier, say in 1-2 years’ time to ensure that there is no local recurrence of the polyp or new polyp.

Question by john

On and off bleeding with stools I prevously was diagnosed with piles and went for a staple piles treatment. At the same time, did a colonoscopy and was declared all clear. One year later, I started getting some bleeding when I wipe after I poo. Concerned, I went to see Specialist, who said I am eating too much fibre. So it was scratching the wound of the piles treatment. Is there such a thing? What is the optimal amount of fibre one should eat? Pls advise. Thank you.

Answered by Dr Fu Wan Pei Cherylin, Consultant, Department of Colorectal Surgery, Singapore General Hospital

Certainly fibre should be taken in moderation. The general recommendation would be to take two servings of fruit and two servings of vegetables per day. An example of one serving of fruit would be a slice of papaya or watermelon, while a quarter plate of cooked vegetables would constitute one serving of vegetables. Although taking adequate fibre is important to maintain a healthy digestive system, excessive fibre intake can give rise to problems as well. Too much dietary fibre may result in abdominal bloating or may sometimes even worsen constipation by making the stool very bulky and hence slowing the passage of stools through the colon. This can sometimes result in very large and hard stools, especially if there is inadequate fluid intake.

"Fibre in the stool" does not actually " scratch" the haemorrhoidectomy (piles surgery) wound, especially if it has healed, given that the surgery was one year ago. However, hard bulky stool can sometimes cause bleeding as it passes through the anal canal by causing an anal fissure (small tear of the anal skin) or causing mild trauma to the scar of the previous piles surgery area.

Having said that, it would be important to ensure that the bleeding that you are experiencing is not from some other problem in your colon or rectum. Your specialist should be able to advise you further if a repeat colonoscopy is necessary depending on your symptoms.

Ref: Q15