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

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

Dr Choo Su Pin, Senior Consultant from the Division of Medical Oncology at National Cancer Centre Singapore, gives detailed answers to your question.

Question by angeline wong

Dear Dr. Choo,

I am 50 years old. I had minor bleeding on the anal area for the past 6 months after each bowel movement. In recent 2 weeks, I have been passing blood mixed with stool. I do not have any pains but have increased frequency of bowel to twice or three times per day instead of once daily. Is this a sign of colorectal cancer?

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

Change in bowel habit and blood mixed with stools are possible symptoms of colorectal cancer. Further investigations such as a colonoscopy should be done.

Question by anggielow

Dear Dr Choo

I'm in my 30s. I have persistent lower abdominal pain & abdominal bloatedness. I don't really keep track of my bowel movment but I don't have the urge to move my bowel very often. Docs say is just chronic constipation. I've been taking large doses of laxative. Lately, sometimes I just pass out gust of water with no/little small bits of stools, sometimes i notice bits of undigested food as well.

Is it a sign that my intestine & colon are starting to stop working properly (due to the taking of laxative)? Are there any treatment? Is there any surgerial option to rid/cure the chronic constipation. I don't wish to have to keep take laxative just to have a bowel movement. Can chronic constipation lead to colorectal cancer?


Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

It is unlikely for someone of your age to have colorectal cancer without any family history of the disease.

Nevertheless, if you have noticed a change in your bowel habits recently, it might be wise to seek the opinion of a gastroenterologist. And no, chronic constipation does not lead to colorectal cancer but it can be a sign of cancer.

Question by sonflower

Dear Dr. Choo

My sister in law was diagnosed with stage four colon cancer. Oncologist advised her to do chemo for life, as her lungs was affected. I was shocked as, I have not heard that a person needs to do chemo for life. I would appreciated it if you could advise how should we take care of her during her chemo treatment and also more information on chemo for life....many thanks

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

Stage 4 colon cancer that has spread to the lungs is usually not curable. In this case, we give chemotherapy to control the cancer’s growth and prolong the patient’s lifespan. This means that the treatment may go on for a long time as long as the chemotherapy is controlling the cancer and the patient is tolerating the chemotherapy.

Chemotherapy is usually stopped when it no longer has an effect on the cancer’s growth, or when the patient has become too weak for treatment because of progression of the cancer or side effects.

During chemotherapy, a patient can become very tired both physically and emotionally. You can help by providing emotional support such as accompanying her for treatment. She should be encouraged to lead a normal, healthy lifestyle which includes eating a nutritious diet, doing light exercise, and having adequate rest.

Question by jadenchia

Dear Doctor

My mum always has abdominal discomfort. She keep have the feeling of bloatedness and this has been on and off for several months. Not very frequent but can’t get rid of it. We did consult our GP, but he only prescribes lactobacillus capsules to my mum. May I know is there any side effects of lactobacillus? Could just the feeling of bloatedness itself consider as symptom of colorectal cancer? She does not have any persistent diarrhoea or constipation, blood or mucus in the stools, no weight loss or lump felt in the abdomen. And may I know beside colorectal cancer, what other reason could it be for causing of this type abdominal discomfort?

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

There are many causes for abdominal discomfort ranging from the benign to the malignant. If her abdominal discomfort has been persisting for months and has been bothering her, I would recommend she seeks a medical opinion again.

Question by pearlynwan

My dad constantly suffering from stomach discomfort and need to run to toilet for a couple of times a day. Three weeks ago, he started seeing blood and some blood clot in the stool.

It continues for a week. After he started taking more fiber, the blood stop. Is this a signal that he might be at risk of colorectal cancer ? Or it is quite common to have blood in stool ?

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

Blood in the stool is most commonly a result of benign piles which is due to constipation. In this case, the blood drips on the tissue or into the toilet bowl after defecation.

However, blood mixed in stools can be a sign of colorectal cancer and is often accompanied by a change in bowel habit e.g increased frequency of defecation each day with change in consistency of stool. If so, further tests are warranted.

Question by sbdtys

Dear Doc My brother is undergoing chemo treatment for colorectal cancer now. How would we know if the treatment is working? He looks pale, tired and loss of appetite all the time.

I read on the internet that “about 5% to 10% of people who develop colorectal cancer have inherited gene defects (mutations) that cause the disease”. Is this statement correct? Should everyone in our family goes for cancer screening? My brother is 35 yrs old.

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

If your brother is undergoing chemotherapy as adjuvant treatment i.e. his colorectal cancer has been completely removed by surgery ( stage 2-3 cancer) and the chemotherapy is being given to prevent the cancer from returning, then only time will tell whether or not the chemotherapy is working. Since there is no visible cancer left in your brother’s body, there is no way of knowing if the chemotherapy is working.

If your brother is undergoing chemotherapy as palliation i.e. he has stage 4 colorectal cancer and chemotherapy is being given to control the cancer’s growth, a scan is usually ordered after 2-3 cycles of chemotherapy to assess if the tumour is shrinking in size.

Tiredness and loss of appetite are common side effects of chemotherapy and they will go away when treatment is stopped.

Most colorectal cancers are sporadic. Only <10% of colorectal cancers are due to inherited gene defects. However your brother is young to be diagnosed with colorectal cancer at 35 years old.

First degree relatives should be screened with a colonoscopy from age 25 years ( i.e. 10 years prior to the age at diagnosis). I would also speak to his cancer specialist about possible genetic screening.

Question by kokmay

Dear Dr Choo,

How alkaline water benefit cancer survivor, especially colorectal and breast cancer? I am quite concern now as I have cancer survivors at home suffering from the mentioned cancer.

Thank you for your time.

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

There is no scientific or medical evidence that alkaline water benefits cancer survivors. A normal healthy diet, regular exercise and a positive outlook have been shown to benefit cancer survivors.

Question by cheekmunks

Dear Dr. Choo,

I am a 24yo female, who got diagnosed with early rectal cancer. I believe it is in stage 1 or 2. After a polypectomy was done, they found malignant cells in the polyp. Unfortunately, resection margins were not clear. The colorectal surgery doctor suggested initially to go for ultra-low anterior resection. Now the plan is for transanal excision.

My questions are:

  1. Should I still get a referral to an oncologist?
  2. What are the complications one can expect after transanal excision? What impact does it have on my quality of life after surgery?

Thank you.

Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

If it is early stage i.e. stages 1-2A, there is no need for an oncologist’s input. Chemotherapy which is givne by an oncologist is only required in higher stage rectal cancer. However I would talk to your colorectal surgeon about screening for family members and whether you may have hereditary rectal cancer as you are very young.

Question by chengseah

Dr Choo,

In my most recent health screening, I was diagnosed with a high level of Helicobacter pylori.

At the time if i do not have a bowel movement for at least 2 days, i will also 100% certain to expect to a blood in my stool and it will take couple of days before the bleed ceased.

I just want to assess on my risk of the colorectal cancer.

Also, is there any cancer screening package that specifically on colongraphy ct scan?

Would that be better than a conventional colonscopy scan?

What are the choice of hospistal provide a colongraphy ct scan?


Answered by Dr.Choo Su Pin Registrar Medical Oncology National Cancer Centre Singapore

Helicobacter pylori infection is not related to colorectal cancer. If you do not have a family history of colorectal cancer nor a personal history of colonic polyps or inflammatory bowel disease ( average risk individual), you should be screened for colon cancer when you reach the age of 50years old.

Colonoscopy is the primary mode of screening. Alternatives include CT colonography and faecal occult blood test. If the latter 2 tests are done and an abnormal lesion is found, you will still need a colonoscopy to obtain a biopsy.

CT colonography is more expensive than the other tests and the rectum needs to be inflated with air during the procedure so this can cause a bit of discomfort. The feacal occult blood test is cheap, simple and non-invasive and it detects blood in stools which can be due to other causes.

SGH has CT colonography.

If you are high risk for colorectal cancer, then screening may have to start earlier and this can be discussed with your GP.

Ref: U11