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Fluorouracil (5FU) and mitomycin C

Fluorouracil (5FU) and mitomycin C is a treatment for anal cancer, find out how you have it and other important information. 

Having chemotherapy alongside a course of radiotherapy is a standard treatment for anal cancer. This combined treatment is called chemoradiotherapy.

The chemotherapy drugs used are:

  • mitomycin C
  • fluorouracil (5FU or FU)

How it works

These chemotherapy drugs destroy quickly dividing cells, such as cancer cells.

How you have it

You have mitomycin and fluorouracil into your bloodstream.

Into your bloodstream

You have the treatment through a drip into your arm. A nurse puts a small tube (a cannula) into one of your veins and connects the drip to it.

You might need a central line. This is a long plastic tube that gives the drugs into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment, which may be for a few months.

When you have it

On the first day of your treatment, you have:

  • an injection of mitomycin
  • a drip (infusion) of fluorouracil that lasts for 4 days

You may stay in hospital while having your chemotherapy.

You start radiotherapy to the anal area on the same day as you begin chemotherapy. You then continue having radiotherapy every weekday (Monday to Friday) for approximately 5 weeks. You have between 25 and 28 sessions (fractions). You can usually go home once your 4 days of chemotherapy are finished if you feel well enough. And you carry on having radiotherapy as an outpatient.

At the beginning of the fifth week of your radiotherapy treatment you have another 4 day drip of fluorouracil.

Tests during treatment

You have blood tests before starting treatment and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Side effects

Important information

Other medicines, food and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment and for a few months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


You may not be able to become pregnant or father a child after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future. Men may be able to store sperm before starting treatment. Women may be able to store eggs or ovarian tissue but this is rare.


Don’t breastfeed during this treatment because the drugs may come through in your breast milk.

Treatment for other conditions

Always tell other doctors, nurses or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.


Don’t have immunisations with live vaccines while you’re having treatment and for at least 6 months afterwards.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and Zostavax (shingles vaccine).

You can:

  • have other vaccines, but they might not give you as much protection as usual
  • have the flu vaccine
  • be in contact with other people who've had live vaccines as injections

Avoid contact with people who’ve had live vaccines taken by mouth (oral vaccines). This includes the rotavirus vaccine given to babies. The virus is in the baby’s urine for up to 2 weeks and can make you ill. So, you mustn't change their nappies for 2 weeks after their vaccination.

You also need to avoid anyone who has had oral polio or typhoid vaccination recently.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Information and help

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About Cancer generously supported by Dangoor Education since 2010.