Colon cancer

An ESCP Guide for Patients

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What is colon cancer?

Colon cancer starts in the large intestine (colon), part of your digestive system. It often begins as small, non-cancerous growths called polyps on the inside of the colon. Over time, some types of polyps - especially adenomas - can turn into cancer.

Catching colon cancer early gives you the best chance for a full recovery, as the cancer can grow and spread if not treated in time.

Role of the colon and rectum

The colon has four sections ascending, transverse, descending, and sigmoid. Its purpose is to:

• Absorb water and nutrients (mainly electrolytes) from food
• Processes and moves waste to the rectum

The rectum acts as a reservoir where stool is stored before a bowel movement.

Anatomy of the colon

Types of polyps and their cancer risk

Different types of polyps can be found in the colon:

Risk factors for colon cancer

You can't change:

• Age: most cases occur after age 50
• Family history/genetics: inherited conditions like Lynch syndrome or FAP increase risk
• Other health issues: such as inflammatory bowel disease or type 2 diabetes

You can change:

• Diet: high-fibre foods help; red and processed meats increase risk
• Exercise: staying active protects your digestive system
• Weight: being overweight increases inflammation in the body
• Smoking and alcohol: both raise the risk of colon cancer

Symptoms of colon cancer

Colon cancer may not cause symptoms early on, so screening is important. If symptoms do appear, they might include:

• Changes in bowel habits: ongoing diarrhoea or constipation
• Blood in your stool: may look red or very dark
• Stomach discomfort: cramps, bloating, or pain
• Tiredness and weakness: often caused by anemia (low red blood cells)
• Unexplained weight loss

How is colon cancer diagnosed?

Doctors use several tests to diagnose colon cancer:

• Faecal occult blood test (FOBT): a stool sample is tested for hidden blood. This non-invasive test detects hidden (occult) blood in the stool, which might be a sign of cancer or polyps. A small stool sample is tested for traces of blood not visible to the eye.
• Colonoscopy: a colonoscopy is the most reliable way to check for colon cancer. It allows doctors to look directly inside your colon and rectum using a small camera. If something unusual is found, it can often be removed or tested right away - sometimes preventing cancer before it starts.
  • Colonoscopy is the gold standard for diagnosing colon cancer because it allows direct visualisation and immediate tissue sampling. The importance of timely colonoscopy cannot be overstated, as early detection is extremely important and polyp removal might render further treatment unnecessary.
• Biopsy: a small tissue sample is taken for microscopic analysis to confirm cancer
• Imaging tests:
  • CT Colonography (virtual colonoscopy): a scan that creates images of the colon when colonoscopy is not possible
  • CT scan: is mainly used to check if the cancer has spread to other organs
• Blood tests: these check for anemia and may include a tumour marker test (CEA test)

Treatment options for colon cancer

• Endoscopic treatment: early-stage cancers may be removed during colonoscopy
• Surgery: includes polypectomy, partial colectomy, or total colectomy
• Targeted therapy and immunotherapy: used in advanced cancer to attack cancer cells
• Chemotherapy: used before or after surgery to kill cancer cells

Your treatment plan depends on the stage of the cancer, your overall health, and your preferences. A team of specialists - including surgeons, oncologists, and radiologists - will work with you to find the best approach. You’ll be involved in every decision.

Surgery

Surgery is the main treatment for rectal cancer.

• Endoscopic removal: for very early cancers during a colonoscopy
• Colonic resection: larger tumours may require removal of part of the colon and nearby lymph nodes. Colonic resection is a surgery to remove part (or sometime) all of the colon where the cancer is located. The main goal is to take out the tumour and nearby tissues to help prevent the cancer from coming back. It's one of the most common and effective treatments for colon cancer.

What happens during surgery?

The surgeon removes the section of the colon where the cancer is located, along with some nearby healthy tissue and lymph nodes. The healthy ends of the colon are then joined back together (this is called an anastomosis).

In some cases, a temporary or permanent stoma may be needed - your team will let you know if this applies to you.

What is a stoma?

A stoma is a surgically created opening in the abdomen that allows stool to leave the body. Depending on the type of surgery and how your body heals, this may be:

• Temporary: often used to allow the bowel to heal after surgery or when complications occur to allow inflammation to disappear; it may be reversed after a few months
• Permanent: needed if reconnection of the colon is not possible

Immunotherapy or targeted therapy

In some cases of advanced rectal cancer, doctors may use targeted therapy or immunotherapy to help fight the disease. These treatments don’t work for everyone, but for some people they can help slow the cancer down or shrink tumours, especially when other treatments haven’t worked. If you are a candidate for these treatments, your cancer team will explain the risks, benefits, and whether they're right for you.

Targeted therapy

Targeted therapy uses special drugs that focus on specific changes or weaknesses in cancer cells. Unlike regular chemotherapy, it tries to attack only the cancer cells while doing less harm to healthy ones. It’s often used when:

• The cancer has spread (metastatic)
• The cancer has certain gene changes (like KRAS or BRAF mutations)

Immunotherapy

Immunotherapy helps your own immune system recognise and attack cancer cells. Some cancers 'hide' from the immune system - this treatment helps unmask them. It may be used in patients with a specific gene condition called MSI-high or dMMR (your doctor may test for this first).

Chemotherapy

Chemotherapy uses special cancer-fighting drugs to slow or stop cancer growth. It may be given:

• Before surgery to shrink the tumour
• After surgery to reduce the risk of cancer coming back
• If the cancer has spread, as a main treatment to control it

Post-treatment care and recovery

Recovery after surgery may include:

• Pain relief and rest
• Wound care: keeping surgery sites clean
• Gradual return to eating normal food
• Colostomy care: if a stoma (opening on the abdomen) was created
• Follow-up checks: long-term follow-ups, including scans, colonoscopies and blood tests to catch any return

Prevention and healthy lifestyle choices

You can reduce your risk by:

1. Limiting processed meats and red meat
2. Maintaining a healthy weight
3. Limiting alcohol
4. Exercising regularly
5. Eating more fibre (vegetables, fruits, whole grains)
6. Quitting smoking

Support for patients and families

A cancer diagnosis can be overwhelming. Support groups, counselling, and medical resources can provide emotional and practical support for patients and families.

Ask your care team for local references both in and outside of the hospital.

Final thoughts

Colon cancer is one of the most treatable cancers - especially when caught early. Screening, healthy habits, and good communication with your healthcare team can make a big difference.

For more information, talk to your healthcare provider today!

Disclaimer

The information provided here is general and hopes to correctly inform the patient to the extent possible. However, this document cannot discuss all aspects of a specific condition or procedure, or of the individual patient.

The decision on which procedure will give you the best result is made by your doctor or colorectal surgeon during consultation and based on shared and informed decision-making with the patient.