Colorectal Cancer Health Center

By Medically reviewed by hellodoktor

Know the basics

What is colorectal cancer?

Colorectal cancer occurs when there are cancerous cells affecting the colon or rectum. Your colon, also known as your large bowel, is the final part of your large intestine of the digestive system. It can be as long as 1.5 meters. When you digest food, the food is moved from your stomach and small intestine into the colon. The colon is responsible for absorbing all the essential nutrients removes waste (stools) from your body. The rectum is the final part of the large intestine where waste is removed.

Colorectal cancer can begin as a growth called a polyp that is formed on the inner wall of the colon or rectum. It is important to monitor and remove these polyps to prevent colorectal cancer.

Colorectal cancer is the third most common cancer in the world, affecting nearly 1.4 million new cases every year.


What are the causes of colorectal cancer?

Like many cancer, colorectal cancer occurs when the cells in the colon and rectal grow at an abnormal rate, leading to a tumor. In colorectal cancer, the cells in the lining of the large intestine are affected and creating a polyp in the colon or rectum. Some polyps become cancerous over time. Colorectal cancer can also occur from cancer from other parts of the body spreading to the colon or rectal.

Colorectal cancer that origins from the colon or rectum is called primary cancer, while cancer that spread from other parts is called metastasis cancer.

Most colorectal cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids). Adenocarcinomas make up more than 95% of colorectal cancers. These cancers start in cells that form glands that make mucus to lubricate the inside of the colon and rectum. When doctors talk about colorectal cancer, they are almost always talking about this type.

Risk factors

Who is at risk of colorectal cancer?

It is recommended that people older than 50 years old should get screening for cancer. There are several risk factors that can increase your chance of getting colorectal cancer. If you have these factors, you should begin screening earlier from a young age.

  • You have had colorectal cancer or polyps in the past.
  • You have a family history of colorectal cancer or polyps.
  • You have ulcerative colitis or Crohn’s disease.
  • You have a hereditary colon cancer syndrome.

Signs and symptoms

What are the symptoms of colorectal cancer?

In the early stage, a polyp might be undetected and cause no symptoms. But as it develops into a large cancer tumor, you might experience some symptoms. Symptoms of colorectal cancer include:

  • Diarrhea or constipation;
  • A feeling that your bowel does not empty completely;
  • Blood (either bright red or very dark) in your stool;
  • Stools are narrower than usual;
  • Frequent gas pains or cramps, or feeling full or bloated;
  • Weight loss with no known reason;
  • Fatigue;
  • Nausea or vomiting.

As these symptoms might also indicate other conditions, you should get checkup at the doctor if you have:

  • Bleeding from your rectum;
  • Blood in your stool or in the toilet after you have a bowel movement;
  • A change in the shape or consistency of your stool (such as diarrhea or constipation lasting several weeks);
  • Cramping pain in your lower stomach;
  • A feeling of discomfort or an urge to have a bowel movement when there is no need to have one;
  • Weakness or fatigue;
  • Unintended weight loss.

Every patient might experience cancer differently. You might not have any symptoms at all or have symptoms to varying degree. One common symptom that people with colorectal cancer have is feeling sick generally and have difficulty in bowel movements.


What are the complications may happen?

The most common complication of colorectal cancer is cancer spreading (metastasize) to other parts of the body. Treatments of colorectal cancer also may lead to some complications such as:

  • Urinary retention;
  • Leakage from the surgical site;
  • Pain;
  • Skin reactions or burns;
  • Mechanical blockages (strictures);
  • Bleeding and radionecrosis (tissue destruction due to the radiation energy);
  • Nausea and vomiting;
  • Diarrhea;
  • Inability to fight infection;
  • Allergic reactions.

Talk to your doctor to find ways to minimize your risk for complications.

Diagnosis and tests

How is colorectal cancer diagnosed?

Most people only get a diagnosis when symptoms appear. However, early colorectal cancer often has no symptoms. Therefore most patients only get a diagnosis when the cancer is advanced. This is why you should get these recommended screening tests routinely to check your condition.

Digital rectal exam

Your doctor will feel for a polyp or growth in your colon by inserting a gloved finger into your rectum.

Barium enema

The doctor will inject a fluid into your rectum (enema) to make the colon show up clearer on x-ray. Your doctor will look at the x-ray to find any abnormality.

Fecal occult blood test

Your doctor will give you a kit to take a stool sample at home. Afterwards, you can bring it to the doctor to check for blood in the stool. You might need to fast certain foods and medications to make the test effective.

Stool DNA test

This is another stool test to check for cancer cells in your stool. If the previous blood test shows positive results, your doctor might request this test.


This test uses a thin, flexible tube and inserts it into your rectum to look at your entire colon. Colonoscopy may be uncomfortable, but it is usually not painful.

Virtual colonoscopy

This new test uses CT scan to make a model of your colon in the computer. If your doctor finds polyps or other abnormalities in your colon, you will need to have a traditional colonoscopy to examine them in more detail or to remove them.

Treatment and management

What are the treatments for colorectal cancer?

If you have cancer of the colon or rectum, your doctor will talk to you about various treatment options.


Surgery is usually the main treatment for colon and rectal cancer. Your doctor will use this method to remove the tumor.


This treatment uses drugs to kill cancer cells. Chemotherapy can lower your body’s immune system, thus you will need to take immunotherapy to prevent infection during treatments. This combined treatment show to lower the spread of cancer more effectively than just chemotherapy alone.

Sometimes your doctor will recommend chemotherapy after surgery to kill off cancer cells that cannot be removed completely. It is also often used when there is a chance of recurrence

Many different drugs are available for chemotherapy and immunotherapy treatments. Your doctor will help you decide which drugs are right for your treatment needs.


This treatment uses radiation to kill cancer cells. It can be used before surgery to reduce the size of the cancer tumor. Sometimes both radiotherapy and chemotherapy are used after surgery.

How can I manage my colorectal cancer?

While there is no guaranteed way that you will not have colorectal cancer, you can develop a healthy lifestyle to lower your risk of cancer as well as coping better if you have colorectal cancer. You can start by working on the basic first:

Regular tests

Having regular checkup can identify colorectal cancer early and increase the chance of successful treatment. If you are currently having colorectal cancer, you need regular checkups to check if there is any new growth or metastasis to other areas. Some common tests are CEA (carcinoembryonic antigen) blood test, CT (computed tomographic) scans.

Eating better

Cancer treatment can be exhausting and eating might be the last thing on your mind. You might have symptoms that make eating difficult such as nausea and vomiting. These side effects of treatment can make you lose weight frequently. You may find it helps to eat small portions every 2 to 3 hours until you feel better. You may also want to ask your cancer team about seeing a dietitian, an expert in nutrition who can give you ideas on how to deal with these treatment side effects.

Rest and exercise

Fatigue in cancer treatment can lead to the reduction of levels of activity. But physical activity can help reduce fatigue. If you are not very active during treatment, it is normal for your fitness, endurance, and muscle strength to decline. Any plan for physical activity should fit your own situation. If you haven’t exercised in a few years, you will have to start slowly, maybe just by taking short walks.

If you are very tired, you will need to balance activity with rest. It is OK to rest when you need to. Sometimes it’s really hard for people to allow themselves to rest when they are used to working all day or taking care of a household, but this is not the time to push yourself too hard. Listen to your body and rest when you need to.

Hello Health Group does not provide medical advice, diagnosis or treatment.

You might also like