Colorectal Cancer

Understanding treatment for colorectal cancer and how it is delivered.

Last modified: March 1, 2022

What are the treatment options for colorectal cancer? Treatment options

The primary treatment options for colorectal cancer include surgery, radiation therapy, chemotherapy, targeted therapy and immunotherapy. The type of treatment you receive will depend on a number of different considerations, such as if you have colon cancer or rectal cancer, the cancer’s stage, your overall health and your treatment preferences. This page aims to give you a comprehensive overview of how colorectal cancer treatment works.

Types of colorectal cancer treatmentTypes of treatment

Colonoscopy for colorectal cancerColonoscopy

A colonoscopy can both diagnose and treat colorectal cancer. The procedure involves inserting a colonoscope (a tube with a camera attached) into the anus, through to the rectum and colon.

Colonoscopies are used for many different purposes.


  • Assess for abnormalities – Look at the lining of the bowel for tumours or areas of inflammation or bleeding.
  • Biopsy – Collect a sample of tissue for analysis.


  • Polypectomy – Remove small growths (called polyps) in the bowel’s lining.
  • Stent insertion – Placement of a plastic tube to relieve an obstruction inside the bowel.
  • Haemostasis –  To stop bleeding.
  • Local Excision – To remove cancerous tissue.

Local excisions are commonly used for early-stage rectal cancer. Methods include:

  • Transanal excision (TAE) – This procedure involves the removal of cancer from the lower rectal wall, including any surrounding rectal tissue. This is done through making minor incisions into the rectum.
  • Transanal endoscopic microsurgery (TEMS) – Specialised equipment is inserted into the anus to remove cancers in the upper rectum which may not be accessible through a transanal excision.
  • Transanal minimally invasive surgery (TAMIS) – Specialised equipment is inserted into the anus to remove the rectal cancer with minimal invasion.

Surgery for colorectal cancerSurgery

Surgery for colorectal cancer is performed to remove cancerous tissue and relieve symptoms when the cancer has advanced. Most people with colorectal cancer will receive surgery as their primary form of treatment. The two approaches for surgery, performed under general anaesthesia, include:

  • Open colectomy – where a long incision is made through the skin and abdominal wall to access your colon or rectum cancer. Typically, half of the colon on the side of your tumour is removed e.g. left sided colon cancers have a left colectomy
  • Keyhole (laparoscopic) colectomy – a minimally invasive procedure that uses three to four small incisions to access the colon or rectum cancer. Keyhole procedures result in less postoperative pain and complications, shorter hospital stay, and faster recovery compared to open colectomy.

Even though they both fall under colorectal cancer, colon cancer and rectal cancer are unique and are treated differently.


A colectomy (also known as a colorectal resection) is a major surgery that involves the removal of all or part of the colon and/or rectum, including nearby lymph nodes.

Colectomies used for colon cancer


The right or left section of the colon is removed.

Sigmoid colectomy

The sigmoid is removed.


Subtotal or total colectomy

All of the colon is removed.



All of the colon and rectum is removed.

High anterior resection

The upper rectum and part of the colon is removed, alongside nearby lymph nodes and fatty tissue.

Colectomies used for rectal cancer

High anterior resection

The lower part of the colon and upper part of the rectum are removed, including nearby lymph nodes.

Abdominoperineal resection or excision (APR or APE)

The sigmoid colon, rectum and the anus are removed. This requires a permanent stoma.

Ultra-low anterior resection

The lower colon and all the rectum are removed. This includes nearby lymph nodes and tissue.

Colonic J-pouch

An internal j-pouch is made from the bowel’s lining to work as the rectum.

Depending on the type of colectomy you receive, your surgeon may make a cut between both ends of your cancer and reconnect them back together (called an anastomosis). Sometimes, the ends of the bowel may not be able to be joined together. In these cases, a new opening will be made in your abdomen. An opening in the large bowel is known as a colostomy, whereas an opening in the small bowel is referred to as an ileostomy. The opening itself is called a stoma.

Stomas divert faecal waste out of the body. This waste is collected through a colostomy or ileostomy bag that is fixed around the stoma. A stoma can be temporary or permanent.

Radiation therapy for colorectal cancerRadiation therapy

Radiation is a common treatment option for rectal cancer but is not generally used for colon cancer. It is typically delivered over the pelvic area in combination with chemotherapy. Types of radiation therapy commonly used for people with colorectal cancer include:

Chemotherapy for colorectal cancerChemotherapy

Chemotherapy uses a range of drugs to destroy and slow the growth of colorectal cancer. These drugs may be delivered at any stage of your colorectal cancer treatment.

Learn more about chemotherapy and how it is delivered.

Chemotherapy for colorectal cancer is delivered in multiple sessions called cycles. This means you will have one to three weeks of rest between receiving an injection or infusion. Your care team will walk you through how many cycles you may need for your course of treatment, with most people completing chemotherapy in a period of four to six months.

Targeted therapies for colorectal cancerTargeted therapies

Targeted therapies use specialised drugs to destroy specific proteins or genes in colorectal cancer cells.

Targeted therapies are only effective for certain colon and rectal cancers, and are generally used to treat advanced colorectal cancers. Your care team will examine the make-up of your cancer cells to determine if targeted therapies are suitable for you.

Immunotherapy for colorectal cancerImmunotherapy

Immunotherapy trains the immune system to recognise and fight colorectal cancer cells that are hiding behind your body’s natural defences. It is commonly used when your colorectal cancer has come back after initial treatment or has spread to other areas in the body.

Treatment by stage of colorectal cancerTreatment by stage

When you are diagnosed with colorectal cancer, your oncologist will develop your treatment plan as part of a multidisciplinary team based on the stage of your cancer and whether you have colon cancer or rectal cancer.

Colon cancerColon cancer

  • Early (Stage I or II) colon cancer

    Surgery is typically used as the first step in treatment for early-stage colon cancer. You may have a local excision, your polyps removed or a partial colectomy in advanced cases to remove a portion of your colon. If the cancer has grown into the wall of the colon, your doctor may also recommend chemotherapy.

  • Locally advanced (Stage III) colon cancer

    Treatment for locally advanced colon cancer will usually involve surgery (colorectal resection) and chemotherapy. If you can’t have surgery or have an advanced cancer that can’t be completely removed through surgery, you may receive chemotherapy and radiation therapy treatment.

  • Advanced (Stage IV) colon cancer

    Treatment for advanced colon cancer usually focuses on palliative care rather than curing the disease. Your care will be tailored to you and your preferences so that you can live as comfortably as possible. Some options include surgery, chemotherapy, targeted therapies, immunotherapy and radiation therapy. Clinical trials can also play an important role in treatment for advanced colon cancer.

Rectal cancerRectal cancer

  • Early (Stage I) rectal cancer

    Like colon cancer, early-stage rectal cancer is usually treated with either a polypectomy, local excision or transanal endoscopic microsurgery (TEM). Alternatively, a more invasive treatment may be needed, such as a low anterior resection or abdominoperineal resection.

  • Locally advanced (Stage II or III) rectal cancer

    Treatment for locally advanced rectal cancer will typically involve both chemotherapy and radiation therapy, followed by surgery. Depending on where your cancer is, the surgical procedure you have can vary. The most common surgeries are a low anterior resection, abdominoperineal resection or proctectomy with colo-anal anastomosis (where the colon is connected to the anus). After surgery, you may receive more chemotherapy depending on your needs.

  • Advanced (Stage IV) rectal cancer

    Depending on the spread of cancer, treatment for advanced rectal cancer may include surgery and chemotherapy. Most commonly chemotherapy and targeted therapy are used as part of systemic treatment. In some cases, radiation therapy is used as a palliative treatment.


For a full list of references, click here.
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