Treatment for bowel (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.
Read about chemotherapy for bowel cancer that has spread (metastatic bowel cancer)
You might have different chemotherapy drugs for cancer of the large bowel (colon cancer).
Find out about chemotherapy for cancer of the large bowel (colon)
You might have chemotherapy:
with radiotherapy before or after surgery - this is called chemoradiotherapy
before or after radiotherapy and before you have surgery
on its own after surgery
for rectal cancer that has spread
Treatment before surgery aims to shrink the cancer and make it easier to remove during surgery. It’s called neo adjuvant treatment (pronounced nee-oh-ad-joo-vant).
Which treatment you have before surgery will depend on the results of your scans. And how fit and well you are.
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.
Find out more about chemoradiotherapy treatment for rectal cancer
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. So it usually takes around 3 to 6 months.
Metastatic bowel cancer means your rectal cancer has spread to another part of your body. It is also called advanced bowel cancer. You might have chemotherapy if you have bowel cancer that has spread. You might also have some different chemotherapy drugs to the ones listed on this page.
Read about chemotherapy for metastatic bowel cancer
The drugs used to treat rectal cancer include:
fluorouracil (5FU)
capecitabine (Xeloda)
oxaliplatin (Eloxatin)
irinotecan (Campto)
You might have a combination of several drugs. For example, you might have a combination of fluorouracil, oxaliplatin and irinotecan. This is called FOLFOXIRI.
The type of drug, or drugs, that 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.
Most of the chemotherapy drugs you have for bowel cancer are given into your bloodstream (intravenously). Capecitabine is a tablet.
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. This means your doctor or nurse won't have to put in a cannula every time you have treatment.
Find out more about central lines
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 healthcare team before you stop taking a cancer drug, or if you have missed a dose.
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.
Watch the video below about what happens when you have chemotherapy. It is almost 3 minutes long.
You need to have blood tests to make sure it’s safe to start treatment. You usually have these a few days before or on the day you start treatment. You have blood tests before each round or cycle of treatment.
Your blood cells need to recover from your last treatment before you have more chemotherapy. Sometimes your blood counts are not high enough to have chemotherapy. If this happens, your doctor usually delays your next treatment. They will tell you when to repeat the blood test.
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.
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
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.
Read more about chemotherapy in the general treatment section
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.
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: 28 Apr 2025
Next review due: 24 Apr 2028
This section is about treatment for cancer that starts in the back passage (rectal cancer). The main treatments are chemotherapy, surgery, radiotherapy and chemoradiotherapy.
The stage of a cancer tells you how far it has grown through the bowel wall and whether it has spread to nearby lymph nodes or other organs. It helps your doctor to know which treatment you need.
Living with bowel (colorectal) cancer may mean you have changes to your diet, sex life or body image. There is support to help you cope.
Bowel cancer means cancer that starts in the colon (large bowel) or back passage (rectum). It is also known as colorectal cancer.
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