Colorectal surgery is a field of medicine in which surgery is performed for diseases of the colon, rectum and anus.

Common conditions seen requiring colorectal surgery as treatment include:

  • Colorectal cancer

  • Diverticular disease

  • Hemorrhoids,

  • Anal abscesses and

  • Fistula

Other less common conditions treated are inflammatory bowel disease (IBD) and pelvic floor disorders.

In Singapore, colorectal cancer (also known as colon cancer) is the most common cancer in men and 2nd most common cancer among women.

For hemorrhoids (commonly known as piles), one in three persons in Singapore suffer from it.

In this Q&A forum, Associate Professor Emile John Tan, Head & Senior Consultant with the Department of Colorectal Surgery at Singapore General Hospital (SGH), a member of the SingHealth group, answers your questions about colorectal surgery in treating these conditions - how effective it is, what are the latest surgical techniques, what criteria makes you suitable for surgery, how to prepare and more.

This 'Ask the Specialist' forum has closed. Thank you for your interest and participation.

1. Question by j**********
Hi, I have gone surgery for colon cancer stage 2 since 3 years ago. The cells were removed and I'm fine from the bi-yearly screening. Would like to know will the cancer cell come back?

Answered by Associate Professor Tan:
If you have been well for 3 yrs this is very good news. You should undergo surveillance with colonoscopy and CT scanning until 5 years have passed to make sure there is no regrowth of tumour in the body.

2. Question by L********
I went for colonoscopy recently. Result was that I have piles. Sometimes, during passing motion, my piles would enlarge. So when I cleaned either with water or paper, I tend to break the skin & starts bleeding. I am 65yo, can my piles be removed?

Answered by Associate Professor Tan:
Yes. There are many treatments for piles nowadays. They can be removed, either by conventional cutting or stapling, and also treated by laser therapy. The newer treatments like stapling and laser are quite comfortable, recovery is quick. All these therapies are available in SGH.

3. Question by 1********
What are the main causes of gut and colorectal problems? To what extent hereditary plays a part?

Answered by Associate Professor Tan:
Usually gut problems can be related to dietary and day to day habits. On the other hand, most gut problems, particularly functional ones, do not have an obvious trigger or cause. Genetics do play a role, particularly in more severe cases such as in colorectal cancer and inflammatory bowel disease.

4. Question by A***
Hi doctor, 
On average how long does it take for colon polyps to turn into cancer if ever and what is the prognosis? Thank you.

Answered by Associate Professor Tan:
Usually each polyp has only a 1-2% chance of transformation in your lifetime. This takes many years to happen and is very variable, depending on the type of cells in the polyp.

5. Question by Y****
Hi Dr,
What are the chances that having polyps discovered (and removed) during a colonoscopy precedes colon cancer (or other grave diseases) years down the road?

Answered by Associate Professor Tan:
If polyps are removed fully then there is no need to worry about those already since they are removed. The worry is mainly if new polyps grow in the next few years. If there is a tendency towards polyp formation then this needs to be addressed by surveillance colonoscopy - 3 to 5 yrs later in most cases.

6. Question by P******
Dear Dr,
I have hemorrhoids piles near the exit of my rectum. It was ligated by surgeon some 13 years ago.
Recent 2 years till this date, my stools have had difficulty passage through the rectum (even though my daily diet consists of brown rice and whole grain bread and veggies).
Frequently, I had to visit the toilet 4-5 times a day because the stools broke into thin strips and small portions.
Will another ligate of my piles solve my stool blockage issues. OR if there is any suitable medical treatment you would recommend. 
Recent colon scans confirm I have NO colon cancer, it is benign.
Thank YOU very much, Dr.

Answered by Associate Professor Tan:
The decision would be based on clinical examination and your personal symptoms. Piles do not usually cause blockage, although there can be a feeling of something in the anus if they are large enough. 
Also if they are large and tend to prolapse ligation may not help much, as it mainly treats bleeding but not size or prolapse. Please come for an examination so we can help you decide best course of action. There are many treatment options nowadays that can be considered that are very comfortable.

7. Question by J**********
Dear Dr,
I did colonoscopy many years ago at SGH and had a few polyps (benign) removed.
After which, I did another colonoscopy in Dec 2020 in a private clinic and had 3 polyps (benign) removed.
Please advise when do I need to follow up with another colonoscopy? Thank you.

Answered by Associate Professor Tan:
That depends on the histology and size of the polyps. Generally if they are ‘adenomas’ one can wait 3 to 5 years for the next surveillance scope.

8. Question by K***
Hi Doctor, my sister is experiencing repeated stoma prolapse one month after her trephine transverse colostomy, and A&E dept helped to push back the prolapse stoma each time. are there any treatments to prevent the stoma prolapse? Thank you doctor.

Answered by Associate Professor Tan:
Stoma prolapse is extremely common and can often occur if the stoma was performed as part of an emergency procedure. Repair is usually performed if the stoma is permanent and unlikely to ever be reversed - this can be done and complexity varies from person to person.

9. Question by P****
Dear Dr,
I had my first piles operation some 20 years ago. Some time ago I had bleeding in one of my morning bowel movement. It stopped bleeding after 3 days. Consulted doctor and was told to do a tie up of the ballooned blood vessel. I am 68 years old and had a stent done 10 years ago. I am on blood thinning, blood pressure and cholesterol medications. I am still considering to go for this procedure. 

I have the following questions:
1.How many times can the anal blood vessels be shortened or removed?
2.What are the possible consequences if all blood vessels are removed for piles prevention?
3.Is there any alternative or new treatment for piles?

Answered by Associate Professor Tan:
There is no limit to how many times rubber banding can be performed, although each time it is done, there is some thickening of the tissue and consequently this becomes harder to do each time. The blood vessels cannot all be removed. Some are always left behind, even if surgical correction is performed. 

There are multiple treatments now available, such as stapled haemorhoidectomy and Laser haemorhoidoplasty. Conventional surgery can also be considered. The newer treatments like stapling and laser do not carry open wounds and are much more comfortable and well tolerated than previous methods. 


About Associate Professor Emile John Tan

Associate Professor Emile John Tan is Head & Senior Consultant with the Department of Colorectal Surgery at the Singapore General Hospital (SGH). He studied Medicine at the University College London Medical School before completing both his basic and higher surgical training in London.

Assoc Prof Emile John Tan completed a year-long fellowship at the Royal Marsden Hospital, London, training in advanced and recurrent colorectal cancer surgery, and spent a further year at the renown St Marks’ Hospital in Harrow, UK, training in advanced laparoscopic surgery, intestinal failure, pelvic floor disease and inflammatory bowel disease, before being appointed Consultant and Clinical Senior Lecturer with Imperial College London, operating on the Chelsea and Westminster and Royal Marsden Hospital Campus.

He also helped to set up a pelvic floor translational research platform on behalf of Imperial College London, and took the opportunity to develop his career as a clinical academic. He was awarded a National Institute for Health (NIHR UK) Academic Clinical Fellowship in 2008, followed by an NIHR award for a Clinical Academic Lectureship in 2011.

Assoc Prof Emile John Tan has published widely in international peer-reviewed journals, and presented internationally. He maintains a strong interest in minimally invasive and open cancer surgery, and pelvic floor disease, in particular laparoscopic prolapse and functional surgery, as well as neuromodulation.

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