Fluorouracil (5FU) and mitomycin C | Cancer Research UK
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Fluorouracil (5FU) and mitomycin C


What fluorouracil and mitomycin is

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

The chemotherapy drugs used are

  • Mitomycin
  • Fluorouracil (also called FU or 5FU)

The links above take you to information about the side effects of these individual chemotherapy drugs.


How you have fluorouracil and mitomycin

You have mitomycin and fluorouracil into your bloodstream (intravenously). You can have them through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have them through a central line, a portacath or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. The tube can stay in place throughout the course of treatment.

On the first day of your treatment, you have an injection of mitomycin. You will also start 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.

You can read about radiotherapy for anal cancer.

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

The side effects associated with this chemotherapy combination are listed below. The underlined links take you to information about each side effect. For more information on general side effects see our cancer drugs side effects section.


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

  • An increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C. You will have regular blood tests to check your blood cell levels
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Bruising more easily due to a drop in platelets – you may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechia)
  • Tiredness and weakness (fatigue) during and after treatment – most people find their energy levels are back to normal within 6 months to a year
  • Loss of appetite
  • Feeling or being sick – this is usually mild and can be well controlled with anti sickness medicines
  • A sore mouth
  • Diarrhoeatell your doctor or nurse if this becomes severe, if you cannot drink to replace the lost fluid, or if it carries on for more than 3 days. You can have medicines to stop the diarrhoea
  • Women may stop having periods (amenorrhoea) – this may be temporary
  • Loss of fertility – you may not be able to become pregnant or father a child after this treatment. 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

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these effects.


Rare side effects

Fewer than 1 in 100 people have these effects.

  • Total hair loss but the hair will grow back once the treatment ends
  • Damage to heart muscle, which is usually temporary but for a small number of people may be permanent. Your doctor or nurse will check your heart before and after your treatment
  • Confusion or unsteadiness

Radiotherapy side effects

Radiotherapy also has side effects and you can find information about side effects of radiotherapy for anal cancer and possible long term radiotherapy side effects.

Having radiotherapy as well as chemotherapy can make side effects more severe.


Important points to remember

You may have a few of the side effects mentioned on this page. They may be mild or more severe. A side effect may get worse through your course of treatment. Or you may have more side effects as the course goes on. This depends on

  • How many times you've had a drug before
  • Your general health
  • How much of the drug you have (the dose)
  • Other drugs you are having

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.

Pregnancy and contraception

These drugs may 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.


Do not breastfeed during this treatment because the drugs may come through in the breast milk.


Immunisations and chemotherapy

You should not have immunisations with live vaccines while you are having chemotherapy or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your chemotherapy. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


Related information


More information about this treatment

This information does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information about these drugs look at the Electronic Medicines Compendium website at www.medicines.org.uk.

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at www.mhra.gov.uk.

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Updated: 30 December 2014