Colon cancer treatment usually depends on the stage of the cancer. Surgery is the main treatment for most cases, and often removes only the affected part of the colon rather than all of it. Chemotherapy may be added before or after surgery, mainly when the cancer has spread to lymph nodes or beyond.

If you or a loved one has recently been diagnosed with colon cancer, you’re likely facing a flood of questions. What happens next? Will you need an operation? Do you also need chemotherapy? It’s a lot to take in, especially when you’re still coming to terms with the diagnosis.

This post — the next in our series on colon cancer — walks you through the main treatment options, with a particular focus on surgery. We’ll explain what a surgeon actually does during the operation, whether they remove part or all of the colon, and how they decide on the best approach for you.

By the end, you should feel more confident about what to expect and better prepared to talk things through with your medical team.

How do doctors decide which treatment you need?

No two cases of colon cancer are exactly alike, so treatment is always tailored to the individual. Your medical team considers several factors before recommending a plan:

• The stage of the cancer — how large the tumour is and whether it has spread.
• The location of the tumour within the colon.
• Your general health and fitness for surgery.
• Your personal preferences and goals for treatment.

For many people, the two main treatments are surgery and chemotherapy. Some patients need only one; others need a combination. Radiotherapy is used less often for colon cancer than for rectal cancer, so surgery tends to take centre stage.

Why is surgery the main treatment for colon cancer?

Surgery is the most common and most effective treatment for colon cancer, especially when it’s caught early. The goal is straightforward: remove the cancer completely, along with a margin of healthy tissue around it, to reduce the chance of it coming back.

For early-stage cancers that haven’t spread, surgery alone may be enough to cure the disease. That’s one of the reasons early diagnosis matters so much — the sooner the cancer is found, the more likely surgery will be successful.

What does the surgeon do during the operation?

This is one of the questions patients ask most often, and understandably so. The idea of colon surgery can sound daunting, but knowing what happens can make it feel far less frightening.

The main operation for colon cancer is called a colectomy. During a colectomy, the surgeon removes the section of the colon that contains the cancer.

Does the surgeon remove all of the colon or just part of it?

In most cases, the surgeon removes only the affected part of the colon — not the whole thing. This is called a partial colectomy (sometimes known as a hemicolectomy, depending on which side is removed).

Here’s roughly how it works:

• The surgeon takes out the portion of colon containing the tumour, along with a margin of healthy tissue on either side.
• Nearby lymph nodes are usually removed too, so they can be checked for cancer cells.
• The two healthy ends of the bowel are then joined back together in a step called an anastomosis.

Removing the entire colon (a total colectomy) is far less common. It’s usually only needed in specific situations — for example, if there are multiple tumours, or if an underlying condition affects the whole colon.

What happens if the two ends of the bowel can’t be joined?

Sometimes the surgeon can’t safely reconnect the bowel straight away. In these cases, they may create a stoma — an opening on the tummy where waste passes into a bag. A stoma can be temporary, giving the bowel time to heal before it’s reversed later, or permanent, depending on the situation. Your surgeon will always discuss this with you beforehand if it’s a possibility.

How does the surgeon decide how to perform the operation?

Surgeons weigh up several things when planning your operation. Their aim is to remove the cancer completely while keeping you as safe and comfortable as possible.

Key factors include:

• The size and position of the tumour. This determines how much of the colon needs to be removed and which surgical approach suits you best.
• Whether the cancer has spread. If it’s reached nearby organs, surgery may be more extensive.
• Your overall health. Fitness, age and other medical conditions all play a part.
• Whether the surgery is planned or an emergency. An urgent operation (for example, if the bowel is blocked) may be handled differently from a planned one.

Open surgery or keyhole surgery — what’s the difference?

Surgeons can perform a colectomy in two main ways:

• Open surgery: a single larger cut is made in the tummy to reach the colon.
• Keyhole (laparoscopic) surgery: several small cuts are made, and the surgeon uses a tiny camera and specialised instruments to carry out the operation.

Keyhole surgery often means less pain, smaller scars and a quicker recovery. However, it isn’t suitable for everyone. Larger or more complex tumours may still need open surgery. Your surgeon will recommend the approach that’s safest and most effective for your particular case.

When is chemotherapy needed for colon cancer?

Chemotherapy uses medicines to destroy cancer cells. Not everyone with colon cancer needs it, but it can be an important part of treatment in certain situations.

Chemotherapy may be recommended:

• After surgery (called adjuvant chemotherapy) to kill any remaining cancer cells and lower the risk of the cancer returning. This is common when the cancer has spread to the lymph nodes.
• Before surgery (neoadjuvant chemotherapy) to shrink a tumour and make it easier to remove.
• For advanced cancer that has spread to other parts of the body, to help control the disease and ease symptoms.

Your oncologist will explain whether chemotherapy is likely to benefit you, along with what to expect from the treatment.

Which treatment is right for you?

There’s no one-size-fits-all answer. As a general guide:

• Early-stage colon cancer is often treated with surgery alone.
• Cancer that has spread to lymph nodes usually calls for surgery followed by chemotherapy.
• Advanced colon cancer may be managed with chemotherapy, sometimes alongside surgery, to control the disease and improve quality of life.

The most important step is an open conversation with your medical team. They’ll base their recommendations on your specific diagnosis and what matters most to you.

Taking the next step in your treatment journey

A colon cancer diagnosis can feel overwhelming, but understanding your treatment options puts some of the control back in your hands. Surgery — usually removing only the affected part of the colon — is the cornerstone of treatment for most people, with chemotherapy added when there’s a higher risk of the cancer spreading or returning.

If you have questions about your diagnosis or treatment plan, write them down and bring them to your next appointment. Your medical team is there to guide you every step of the way. And do keep an eye out for the next post in our colon cancer series, where we’ll continue to help you make sense of your journey.

Frequently asked questions

Does colon cancer surgery always remove the whole colon?

No. In most cases, surgeons remove only the section of colon containing the tumour, along with a small margin of healthy tissue and nearby lymph nodes. This is called a partial colectomy. Removing the entire colon is far less common and reserved for specific situations.

Will I need a stoma after colon cancer surgery?

Not always. Many people have the two ends of their bowel joined back together during surgery. A stoma is only needed when the bowel can’t be safely reconnected straight away. When it is required, it may be temporary or permanent, and your surgeon will discuss this with you in advance.

Do I need chemotherapy if I have surgery for colon cancer?

Not necessarily. Early-stage colon cancer can often be cured with surgery alone. Chemotherapy is usually recommended when the cancer has spread to the lymph nodes or beyond, either to reduce the risk of it returning or to help control advanced disease.

How long does it take to recover from colon cancer surgery?

Recovery varies from person to person. Keyhole (laparoscopic) surgery generally allows a quicker recovery than open surgery, with less pain and smaller scars. Your medical team will give you personalised advice based on the type of operation you have and your overall health.