Information about surgery, personalised treatment options and side effects.


Surgery is often the main treatment for earlier-stage colorectal cancers. The type of surgery carried out depends on the stage (extent) of the cancer, where it is, and the goal of the surgery.

Surgery for Colon Cancer

Local therapy: Polypectomy and local excision

Some early colorectal cancers (stage T0is and some early Stage 1 tumours) and most polyps can be removed during a colonoscopy. The procedure is called a polypectomy. It is usually done by passing a wire loop through the colonoscope to cut the polyp painlessly off the wall of the colon with an electric current.

A local excision is a slightly different procedure. Tools are used through the colonoscope to remove small cancer lesions on the inside lining of the colon along with a small amount of surrounding healthy tissue on the wall of colon.

Partial resection of the bowel with anastomosis

Tumours that cannot be removed with local therapies will need more extended surgery.

A surgeon will remove a part of the colon, also called a partial resection or hemicolectomy, removing the cancer and a small amount of healthy tissue around it. The two ends of the remaining colon are sewn or stapled back together – this is called anastomosis.

Depending on the location of the tumour these resections can be done in different ways:

  • If the tumour is located in the right side of the colon-the ascending colon-this is called
  • a right hemicolectomy
  • If the tumour is located in the left side of the colon-the descending colon-this is called
  • a left hemicolectomy
  • If the tumour is located in the sigmoid colon-this is called a sigmoid resection
  • Right and left hemicolectomies are sometimes extended to the transverse colon and are then called extended (right or left) hemicolectomy.

Lymph nodes and blood vessels

In addition the surgeon will also explore of the invasion of lymph nodes and blood vessels.

At least 12 nearby lymph nodes are also removed to perform accurate staging.

Surgery: How is it done?

Abdominal surgery can be done in 2 ways:

  • Laparotomy: The surgery is done through a single long incision (cut) in the abdomen
  • Laparoscopy: The surgery is done through many smaller incisions and with special tools. A laparoscope is a long, thin lighted tube with a small camera and light on the end that lets the surgeon see inside the abdomen. It’s put into one of the small cuts, and long, thin instruments are put in through the others to remove part of the colon and lymph nodes

Because the incisions are smaller in a laparoscopic-assisted hemicolectomy than in an open colectomy, this procedure is minimally invasive. Patients often recover faster and may be able to leave the hospital sooner than they would after an open colectomy. But this type of surgery requires special expertise, and it might not be the best approach for everyone.

You should discuss the type of surgery with your surgeon.

Surgery for Rectal Cancer

Surgery is usually the main treatment for rectal cancer often in combination with chemotherapy and radiotherapy. Again the type of surgery used depends on the stage (extent) of the cancer, where it is and the goal of the surgery.

Local therapy: Polypectomy and local excision

Some early rectal cancers (stage T0is and some early Stage I tumours) and most polyps can be removed during a colonoscopy. The procedure is called a polypectomy. It is usually done by passing a wire loop through the colonoscope to cut the polyp painless off the wall of the rectum with an electric current.

A local excision is a slightly different procedure. Tools are used through the colonoscope to remove small cancer lesions on the inside lining of the colon along with a small amount of surrounding healthy tissue on the wall of the rectum.

Transanal Excision (TAE)

This procedure can be used to remove some early Stage I rectal cancers that are relatively small and not too far from the anus.

Today, experienced colorectal cancer surgeons can often perform surgery through the anus and remove only the rectal tumors and small amounts of surrounding tissue while leaving the anus and sphincter intact.

This transanal resection is done with instruments that are put into the rectum through the anus.

Transanal endoscopic microsurgery (TEM)

This procedure can be used for early Stage I cancers that are located higher in the rectum and cannot be reached using the standard transanal resection.

Guided by a video monitor, the surgeon utilises special equipment, up through the anal canal to remove the tumour and lymph nodes.

Because both TAE and TEM do not involve cutting open the abdomen the healing time is much shorter.

Low anterior resection (LAR)

Some Stage I rectal cancers and most Stage II or III cancers in the upper part of the rectum (close to where it connects with the colon) can be removed by low anterior resection (LAR). During the operation the part of the rectum containing the tumour is removed with the surrounding lymph nodes. The colon is then attached to the remaining part of the rectum.

In selected patients the surgeon needs to create a connection between the colon and the wall of the abdomen so the colon has time to heal before stools pass again. The edges of the colon are then stitched to the skin of the abdominal wall to form an opening called an ostomy or stoma.

The stool can then pass through this opening in your abdomen. There are  different types of colostomies based on where they are located on the colon.

Temporary or permanent stoma?

The stoma is usually temporary meaning that – when the tumour is resected and the colon has had time to heal – a second operation is performed to join the two ends of the colon together (anastomosis) and to close the stoma.
The stoma may be permanent in some patients (e.g. those with very low position of a tumour in the rectum).

Proctectomy with colo-anal anastomosis

Some Stage I and most Stage II and III rectal cancers in the middle and lower third of the rectum, require removing the entire rectum (called a proctectomy). All the lymph nodes near the rectum also have to be removed. The colon is then connected to the anus (called a colo-anal anastomosis) so that the patient will pass the stool in the usual way.

Sometimes the patient may need a short-term, temporary ileostomy (where the end of the ileum, the last part of the small intestine, is connected to a hole in the abdominal skin) while the bowel heals. A second operation is then done to reconnect the intestines and close the ileostomy opening.

Abdominoperineal resection (APR)

This type of surgery can be used to treat some Stage 1 cancers and many Stage II or cancers in the lower part of the rectum when the tumour is growing into the sphincter muscle (the muscle that keeps the anus closed and prevents stool leakage) or the nearby muscles that help control urine flow.

This operation is more invasive than a low anterior resection because the anus is removed a permanent colostomy is created to allow stool to leave the body.

Risk Factors and Side Effects of Surgery

  • Risk factors: Some risks are common for every surgical intervention performed under general anaesthesia. These complications are unusual and include deep vein thrombosis, heart or breathing problems, bleeding, infection or reaction to the anaesthesia. These can be prevented by thorough medical evaluation before surgery.
  • Side effects: A side effect is a secondary, typically undesirable one from a drug or medical treatment. These effects are unplanned and can cause physical or emotional reactions. Not all side effects will occur.

After a surgical intervention on the colon it can be quite normal to experience problems of intestinal motility. These can include colicky pain, diarrhoea, constipation and nausea.

There might be other side effects so always ask your treatment team for a complete list and mention side effects if they bother you as there are ways to help you feel better.

After surgery

Following surgery, no other treatment may be required. However, to reduce the chances of any cancer cells remaining in the area, after surgery the patient may undergo chemotherapy, known as ‘adjuvant chemotherapy’.

Our immune system produces immune cells that help us fight infections and ‘foreign’ cells, including cancer cells. To fight cancer cells, immune cells infiltrate the tumour, meaning that they penetrate the tumour and sit among cancer cells. Recent studies have uncovered that some immune cells, which have infiltrated into the tumour, hold key information about the ability of our body to fight the tumour cells. This information can help us understand how the cancer will evolve.

It is now possible to analyse the tumour obtained after surgery to assess the density and type of immune cells that are present in the tumour. These infiltrating immune cells, known as T-lymphocytes, can be used as biomarkers, allowing to predict how likely it is that an early stage colorectal cancer will return (or relapse) after surgery. The more immune cells infiltrate into the tumour, the lower the risk of the cancer to relapse. The amount of these immune cells can be now calculated producing a score linked to a clinical outcome, which when added to the traditional tumour staging system gives a clearer picture about the patient’s risk profile and, therefore, guides the physician to adjust his treatment decision.

The test results can indicate a higher or lower likelihood of relapse and help to manage the patient accordingly, while maintaining the quality of life at the best possible level. Depending on the test results, the treatment may be increased, decreased or even completely avoided. The treating clinician, guided by the patient’s results, would be the one making that decision.

The procedure for the test is fairly simple. With the patient’s consent, tumour tissue is sent to central certified labs; a specialised software dedicated to this test is used for digital pathology analysis. The result of the test allows the doctor to have reliable, complete, and timely information on the patient’s cancer and, thus, better adapt the appropriate treatment for each patient.

We encourage patients to participate in the decision-making discussion with their physician and understand how their own immune system can help their treatment in this highly innovative framework of personalized medicine. With such a refinement in diagnostic information, over-treatment or under-treatment with adjuvant chemotherapy is prevented. However, testing for these specific biomarkers is not currently reimbursed by the national health systems. In the meantime, insurers and the provider company have set up plans to offer solutions to cover costs case by case for this post-surgery diagnostic tool.

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