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Dr Zee Ying Kiat, a Senior Consultant in Medical Oncology at Parkway Cancer Centre, explains what to look out for and the arsenal of treatments for the disease.

Colorectal cancer is the most common cancer among men and second most common cancer among women¹ in Singapore. Also known as colon cancer or large intestine cancer, the disease is one of the top three causes of cancer-related deaths in Singapore.

However, there has been an increase in the survival rate of individuals with colorectal cancer thanks to new forms of therapy and improvements in treatment procedures. Here are 6 things to know about the disease and its treatment:

1. Age is the largest risk factor of colorectal cancer

   The likelihood of developing colorectal cancer increases as one gets older. About 90 per cent of cases are diagnosed in individuals aged 50 or over, compared to 0.5 per cent of cases in individuals below the age of 30, with slight male predominance.

   Other risk factors for colorectal cancer include a strong family history of colorectal cancer, certain inherited conditions such as hereditary non-polyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP), and polyps in the colon.

2. Symptoms do not show in early stages of the disease

   Colorectal cancer does not usually produce symptoms in early stages of the disease.

   When symptoms do appear, they vary based on the size and location of the cancer. The common symptoms are:

   • A change in bowel habits, including diarrhoea or constipation
   • Presence of blood in the stool
   • Persistent abdominal discomfort, such as cramps, bloating or pain
   • A feeling of incomplete bowel emptying
   • Unexplained weight loss

   Screening and early detection can increase the likelihood of treating the cancer effectively.

3. Treatments are becoming more precise and personalised

   More precise treatment procedures and personalised treatment plans have contributed to the increase in survival rates for colorectal cancer over the years.

   The type of treatment recommended will depend on several factors, including the stage of the cancer and the patient’s overall health. Here are some broad strategies for treating colorectal cancer:
   
   Surgery: The most common and effective treatment for colorectal cancer, surgery removes the section of the colon with cancerous growth. Over the years, surgery has evolved from open surgery into more precise procedures such as laparoscopic surgery to minimise the size of the incisions needed. With smaller incisions, patients experience less pain and recover more quickly.
   
   Chemotherapy: Chemotherapy uses chemicals to kill fast-growing cancer cells in the body. It can be used with curative intent, or for symptom control and prolongation of life.
   
   Radiation therapy: Radiation treatment uses machines known as linear accelerators to deliver high doses of radiation to kill cancer cells and shrink tumours. 
   
   Immunotherapy: In a way similar to vaccination against viruses, immunotherapy harnesses the body’s immune system to seek and destroy cancer cells, offering long-term control of the disease.
   
   Targeted therapy: Targeted therapy involves the use of drugs designed to block molecules that promote cancer cell growth and spread. Compared to traditional therapies, targeted therapy offers more precise treatment that reduces damage to healthy surrounding cells.  

4.  Early stages of colorectal cancer are often treatable

   Generally, colorectal cancer is highly treatable in its early stages, before it has had a chance to spread. 
   
   Surgery is the foundation of curative therapy in patients with early stage colorectal cancer. Additional treatment with chemotherapy and radiotherapy may sometimes be needed to improve the chance of cure. 
   
   At more advanced stages where the cancer has spread, the mainstay of treatment would be with chemotherapy, targeted therapy and sometimes, immunotherapy. Surgery may be considered in certain situations to relieve symptoms. In a selected group of patients where the spread of colorectal cancer is limited to the liver, aggressive surgery to remove the primary cancer and affected area(s) of the liver may still offer the prospect of cure.
   
   Doctors often combine different treatments for greater effect, depending on the patient’s symptoms and overall health. 

5. Genomic profiling can help in treatment 

   Genomic profiling has been useful in tailoring treatment to the characteristics of the cancer and genetic make-up of the individual. 
   
   It involves studying the genes in the individual or specific cell type in a laboratory setting, to observe how these genes interact with each other and the environment. Genomic profiling may be used to find out why certain individuals get certain diseases while others do not, or why different individuals react in different ways to the same drug. This information can be used to develop new ways of diagnosing, treating, and preventing diseases.
   
   

6. Colorectal cancer can be passed down to family members

    It is estimated that about 5 per cent of all colorectal cancers may be hereditary. 
   
   Individuals with a strong family history of colorectal cancer are at increased risk of developing the disease by nearly two times. Those with inherited conditions such as FAP and HNPCC also have increased risk. 
   
   If you have a strong family history of colorectal cancer, you should see your doctor. You may be referred to a genetics clinic, where your family history will be analysed to help work out the likely risk of developing the disease. 

¹Singapore Cancer Registry, 2011–2015