Chemotherapy for rectal cancer

Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. The drugs circulate throughout the body in the bloodstream.

This page is about chemotherapy for cancer of the back passage (rectum) that hasn’t spread to another part of the body.

When do you have chemotherapy?

You might have chemotherapy: 

  • with radiotherapy (chemoradiotherapy) before or after surgery
  • on its own after surgery
  • for advanced cancer

Chemoradiotherapy before surgery aims to shrink the cancer and make it easier to remove during surgery. It’s called neo adjuvant chemoradiotherapy (pronounced nee-oh-ad-joo-vant).

You might have chemoradiotherapy after surgery if you didn’t have it before, and the risk of your cancer coming back is higher than the surgeon previously thought.

You might have chemotherapy on its own after surgery if you have a high risk of your cancer coming back. It’s called adjuvant chemotherapy.

You usually have adjuvant chemotherapy every 2 to 3 weeks depending on what drugs you have. Each 2 to 3 week period is called a cycle. You may have up to 8 cycles of chemotherapy.

If you have advanced cancer

Advanced bowel cancer means your rectal cancer has spread to another part of your body. You might have chemotherapy if you have advanced bowel cancer.

Types of chemotherapy

The drugs used to treat rectal cancer include:

  • fluorouracil (5FU)
  • capecitabine (Xeloda)
  • oxaliplatin (Eloxatin)
  • irinotecan (Campto)

You might have a combination of several drugs. The type of drug you have depends on different factors. These include your risk of the cancer coming back and whether you have any other medical conditions.

The doctor also considers the drug side effects and how you have the chemotherapy. They will discuss this with you so you can decide on your treatment plan together.

How you have chemotherapy

Most of the chemotherapy drugs you have for bowel cancer are given into your bloodstream (intravenously). Capecitabine is a tablet.

Into your bloodstream

You have treatment through a thin short tube (a cannula) that goes into a vein in your arm each time you have treatment.

Or you might have treatment through a long line: a central line, a PICC line or a portacath. These are long plastic tubes that give the drug into a large vein in your chest. The tube stays in place throughout the course of treatment.

Diagram showing a central line

Tablets

You must take tablets and capsules according to the instructions your doctor or pharmacist gives you.

Whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream.

You should take the right dose, not more or less.

Talk to your specialist or advice line before you stop taking a cancer drug.

Where you have chemotherapy

You usually have treatment into your bloodstream at the cancer day clinic. You might sit in a chair for a few hours so it’s a good idea to take things in to do. For example, newspapers, books or electronic devices can all help to pass the time. You can usually bring a friend or family member with you.

You have some types of chemotherapy over several days. You might be able to have some drugs through a small portable pump that you take home.

For some types of chemotherapy you have to stay in a hospital ward. This could be overnight or for a couple of days.

Some hospitals may give certain chemotherapy treatments to you at home. Your doctor or nurse can tell you more about this.

Before you start chemotherapy

You need to have blood tests to make sure it’s safe to start treatment. You have these either a few days before or on the day you start treatment. You have blood tests before each round or cycle of treatment.

Side effects

Common chemotherapy side effects include:

  • feeling sick
  • loss of appetite
  • losing weight
  • feeling very tired
  • a lower resistance to infections
  • bleeding and bruising easily
  • diarrhoea or constipation
  • hair loss
Contact your advice line or your doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

Side effects depend on:

  • which drugs you have
  • how much of each drug you have
  • how you react

Tell your treatment team about any side effects that you have.

Most side effects only last for a few days or so. Your treatment team can help to manage any side effects that you have.

DPD deficiency

Between 2 and 8 out of 100 people (2 to 8%) have low levels of an enzyme called dihydropyrimidine dehydrogenase (DPD) in their bodies. A lack of DPD can mean you’re more likely to have severe side effects from capecitabine or fluorouracil. It might take you a bit longer to recover from the chemotherapy. These side effects can rarely be life threatening.

Before starting treatment with capecitabine or fluorouracil you have a blood test to check levels of DPD. So you may start treatment with a lower amount (dose) of the drug or have a different treatment. Your doctor or nurse will talk to you about this.

When you go home

Chemotherapy for bowel cancer can be difficult to cope with. Tell your doctor or nurse about any problems or side effects that you have. The nurse will give you telephone numbers to call if you have any problems at home.

Last reviewed: 
11 Feb 2022
Next review due: 
11 Feb 2025
  • Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the management of cancer of the colon, rectum and anus (2017) – diagnosis, investigations and screening
    C Cunnigham and others
    Colorectal disease, 2017. Volume 19, Pages 1-97                                                                                                                  

  • Rectal cancer: ESMO Clinical Practical Guidelines for diagnosis, treatment and follow up
    R Glynne-Jones and others
    Annals of Oncology, 2017. Volume 28, Pages 422-440

  • Colorectal cancer
    British Medical Journal (BMJ) Best Practice Online (Accessed February 2022)

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