CMF
CMF is used to treat breast cancer.
What is CMF?
CMF is used to treat breast cancer. It is best to read this information with our general information about chemotherapy and the type of cancer you have.
CMF comes from the initials of the drugs used:
Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.
More information about this treatment
This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.
You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.
DPD testing before treatment
Before starting this treatment, you should have a blood test. This test checks for gene changes that affect how your body produces DPD. DPD is an enzyme that helps the body break down 5FU.
If you have low DPD levels or no DPD (DPD deficiency), you have more risk of serious or life-threatening side effects from 5FU. To reduce your risk, your doctor may give you:
- a lower dose of 5FU to start with
- a different type of chemotherapy.
Having low DPD levels does not usually cause any symptoms. Without a test, you will not know whether your DPD levels are low. Testing finds most people who are affected, but not all. Your doctor, nurse or pharmacist can give you more information about your risk of DPD deficiency, before you start treatment.
How CMF is given
You will be given CMF in the chemotherapy day unit or during a stay in hospital. A chemotherapy nurse will give it to you.
During treatment you usually see a cancer doctor, a chemotherapy nurse or a specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.
Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that your blood cells are at a safe level to have chemotherapy.
You will see a doctor or nurse before you have chemotherapy. They will talk to you about your blood results and ask you how you have been feeling. If your blood results are okay, the pharmacist will prepare your chemotherapy. Your nurse will tell you when your treatment is likely to be ready.
Your nurse usually gives you anti-sickness (anti-emetic) drugs before the chemotherapy. You may have the chemotherapy drugs through:
- a cannula – a short, thin tube the nurse puts into a vein in your arm or hand
- a central line – a fine tube that goes under the skin of your chest and into a vein close by
- a PICC line – a fine tube that is put into a vein in your arm and goes up into a vein in your chest
- an implantable port (portacath) – a disc that is put under the skin on your chest or arm and goes into a vein in your chest
- as tablets that you swallow.
Your course of chemotherapy
You usually have a course of several cycles of treatment over a few months. Your nurse or doctor will talk to you about how the treatment will be given. They may give you a copy of a treatment plan to take home with you.
Usually, your nurse gives you cyclophosphamide, methotrexate and 5 FU on the first day. This is day 1 of treatment. You will then have the same treatment a week later (day 8). You then have a rest period before starting another cycle. Each cycle usually takes 28 days (4 weeks).
Sometimes the cyclophosphamide is given as tablets instead of an injection. You take the tablets every day, starting on day 1, for 2 weeks.
Your doctors will tell you how many cycles of treatment you will have.
CMF is sometimes given as a 21day cycle. Your doctors will explain your treatment plan to you.
Taking cyclophosphamide tablets
The nurse or pharmacist will give you the tablets to take home. Always take them exactly as explained. This is important to make sure they work as well as possible for you.
Your nurse or pharmacist may also give you anti-sickness drugs and other medicines to take home. Take all your capsules or tablets exactly as they have been explained to you.
The tablets must be swallowed whole with a glass of water. They should not be chewed or crushed.
Take them early in the day and drink plenty of fluid. Take them at the same time every day. Try to take the tablets on an empty stomach. But if this causes you to feel sick (nausea), then take them with or after food.
If you forget to take the tablets, you should take the missed dose as soon as possible within the same day. If a full day has gone by, let your doctor or nurse know. Do not take a double dose unless your doctor tells you to.
Other things to remember about your tablets:
- Wash your hands after taking your tablets.
- Other people should avoid direct contact with the chemotherapy drugs.
- Keep them in the original package and at room temperature, away from heat and direct sunlight..
- Keep them safe and out of sight and reach of children.
- If you are sick just after taking the tablets, contact the hospital. Do not take another dose.
- If your treatment is stopped return any unused tablets to the pharmacist.
Folinic acid tablets
Your doctor may give you folinic acid tablets to take 24 hours after having the methotrexate. They may do this if you have severe side effects from methotrexate, such as:
- a very sore mouth or eyes
- severe diarrhoea.
About side effects
We explain the most common side effects of this treatment here. We also include some that are less common.
You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here.
Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you:
- drugs to help control some side effects
- advice about managing side effects.
It is important to take any drugs exactly as explained. This means they will be more likely to work for you.
Serious and life-threatening side effects
Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.
If your body does not produce enough of an enzyme called DPD, you may have a higher risk of severe or life-threatening side effects.
Contact the hospital
Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.
Side effects while treatment is being given
Allergic reaction
Some people have an allergic reaction while having this treatment. Before treatment, you will have medicines to help prevent or reduce any reaction.
Signs of a reaction can include:
- feeling hot or flushed
- shivering
- itching
- a skin rash
- feeling dizzy or sick
- a headache
- feeling breathless or wheezy
- swelling of your face or mouth
- pain in your back, tummy or chest.
Your nurse will check you for signs of a reaction during your treatment. If you feel unwell or have any of these signs, tell them straight away. If you do have a reaction, they can treat it quickly.
Sometimes a reaction happens a few hours after treatment. If you develop any of these signs or feel unwell after you get home, contact the hospital straight away on the 24-hour number.
Always call 999 if swelling happens suddenly or you are struggling to breathe.
The drug leaks outside the vein
If the drug leaks outside the vein, it can damage the surrounding tissue. This is called extravasation. Extravasation is not common but if it happens it is important to treat it quickly. Tell your nurse straight away if you have any stinging, pain, redness or swelling around the vein.
If you get any of these symptoms after you get home, contact the doctor or nurse straight away on the contact telephone number they gave you.
Pain along the vein
You may get pain at the place where the injection is given or along the vein. If you feel pain, tell your nurse or doctor straight away so that they can check the site. They may give the drug more slowly or flush it through with more fluid to reduce pain.
Common side effects
Risk of infection
This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If your white blood cell count is low, you may be more likely to get an infection. A low white blood cell count is called neutropenia.
An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. If you have any of the following symptoms, contact the hospital straight away on the 24-hour number:
- a temperature above 37.5°C
- a temperature below 36°C
- you feel unwell, even with a normal temperature
- you have symptoms of an infection.
Symptoms of an infection include:
- feeling shivery and shaking
- a sore throat
- a cough
- breathlessness
- diarrhoea
- needing to pass urine (pee) often, or discomfort when you pass urine.
It is important to follow any specific advice your cancer treatment team gives you.
Your white blood cell count will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time, until your cell count increases.
Bruising and bleeding
This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.
If the number of platelets is low, you may bruise or bleed easily. You may have:
- nosebleeds
- bleeding gums
- heavy periods
- blood in your urine (pee) or stools (poo)
- tiny red, brown or purple spots that may look like a rash – these spots can be harder to see if you have black or brown skin.
If you have any unexplained bruising or bleeding, contact the hospital straight away on the 24-hour number. You may need a drip to give you extra platelets. This is called a platelet transfusion.
Anaemia (low number of red blood cells)
This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may feel:
- very low in energy
- breathless
- dizzy and light-headed.
If you have these symptoms, contact the hospital straight away on the 24-hour number. You may need treatment for anaemia. If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.
Bladder problems
Cyclophosphamide may irritate your bladder and cause discomfort when you pass urine (pee). Drink at least 2 litres (3½ pints) of fluids during the 24 hours following chemotherapy. It is also important to empty your bladder regularly and to try to pass urine as soon as you feel the need to go.
If you feel any discomfort or stinging when you pass urine, or if you notice any blood in it, contact the hospital straight away.
Feeling sick
Your doctor, nurse or pharmacist will prescribe anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you to, even if you do not feel sick. It is easier to prevent sickness than to treat it after it has started.
If you feel sick, take small sips of fluid often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or if you are sick (vomit) 1 to 2 times in 24 hours, contact the hospital on the 24-hour number as soon as possible. They will give you advice. They may change your anti-sickness treatment. Let them know if you still feel sick.
Loss of appetite
This treatment can affect your appetite. Don’t worry if you do not eat much for 1 or 2 days. But if your appetite does not come back after a few days, or if you are losing weight, tell your doctor, nurse or pharmacist. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.
Sore mouth and throat
This treatment may cause a sore mouth and throat. You may also get mouth ulcers. This can make you more likely to get a mouth or throat infection. Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.
Contact the hospital straight away on the 24-hour number, if:
- a sore mouth or throat affects how much you can drink or eat
- your mouth, tongue, throat or lips have any blisters, ulcers or white patches.
They can give you advice, and mouthwash or medicines to help with the pain or to treat any infection. Follow their advice and make sure you:
- drink plenty of fluids
- avoid alcohol and tobacco
- avoid food or drinks that irritate your mouth and throat.
Diarrhoea
This treatment may cause severe diarrhoea. Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.
Your doctor, nurse or pharmacist may give you anti-diarrhoea drugs to take at home.
If you have diarrhoea or a mild increase in stoma activity, follow their advice about:
- taking anti-diarrhoea drugs
- how much and what type of fluids to drink
- any changes to your diet that might help.
Contact the hospital straight away on the 24-hour number if:
- you have diarrhoea at night
- you have uncomfortable stomach cramps
- you have diarrhoea 4 or more times in a day
- you have a moderate increase in stoma activity
- the anti-diarrhoea drugs do not work within 24 hours.
You may need to give a stool sample, or go to hospital to have fluids through a drip or antibiotics.
Constipation
This treatment can cause constipation. Constipation means that you are not able to pass stools (poo) as often as you normally do. It can become difficult or painful. Here are some tips that may help:
- Drink at least 2 litres (3½ pints) of fluids each day.
- Eat high-fibre foods, such as fruit, vegetables and wholemeal bread.
- Do regular gentle exercise, like going for short walks.
If you have constipation, contact the hospital on the 24-hour number for advice. They can give you drugs called laxatives to help.
If you have not been able to pass stools for over 2 days and are being sick, contact the 24-hour number straight away.
Indigestion
Hair loss
Your hair will get thinner. Or you may lose all the hair from your head. You may also lose your eyelashes and eyebrows, as well as other body hair. Hair loss usually starts after your first or second treatment.
If you want to cover up hair loss, there are different ways you can do this. Your nurse will give you information about coping with hair loss.
Remember to protect your skin from the sun. Use suncream with a sun protection factor (SPF) of at least 30 on your scalp. Or cover up with a hat or scarf.
Hair loss is almost always temporary. Your hair will usually grow back after treatment ends.
Feeling tired
Feeling tired is a common side effect of this treatment. It is often worse towards the end of treatment and for some weeks after it ends. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can help you feel less tired.
If you feel sleepy, do not drive or use machinery.
Eye problems
This treatment may make your eyes feel sore, red and itchy (conjunctivitis). Your doctor can prescribe eye drops to help treat this. Your pharmacist will tell you how to use your eye drops. It is important to follow their advice.
It may also make your eyes more sensitive to light and cause blurry vision. If you have pain or notice any change in your vision, always tell your doctor or nurse.
Headaches
This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.
Less common side effects
Skin changes
CMF may affect your skin. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day. CMF can cause a rash, which may be itchy.
During treatment and for several months afterwards, you will be more sensitive to the sun and your skin may burn more easily than usual. If you are out in the sun, use a suncream with a high sun protection factor (at least SPF 30) to protect your skin. You should also cover up with clothing and a hat.
If you have ever had radiotherapy, the area that was treated may become red or sore. Your skin may darken. People with darker skin may develop noticeable light patches on their skin.
Always tell your doctor or nurse about any skin changes. They can give you advice and may give you creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.
Very rarely, a much more serious skin condition can occur. You may have a skin rash which then blisters and your skin can peel. You may also feel unwell with flu-like symptoms such as a high temperature and joint pain. If you have any of these symptoms, contact your doctors straight away.
Nail changes
This treatment can affect your nails. They may grow more slowly or break more easily. You might notice ridges or white or dark lines across your nails. These changes usually disappear as the nails grow out after treatment. Sometimes nails can become loose or fall out.
If the skin around your nails becomes sore and swollen, contact the hospital straight away on the 24-hour number. These might be signs of an infection.
Tips to look after your nails:
- Keep your nails clipped short and clean.
- Avoid using very hot water when washing your hands or bathing.
- Moisturise your nails and cuticles regularly.
- It is okay to use water-based nail polish - but ask your cancer team if you want to use false nails, gels or other acrylics during treatment.
- Wear gloves to protect your nails when working in the house or garden.
- If your toenails are affected, wear well-fitting shoes, or shoes with open toes to cushion them.
Tell your doctor or nurse about any changes to your nails. They can give you advice or arrange for you to see a podiatrist. They are a foot care specialist.
Changes to your taste
Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. You may also get a bitter or metallic taste in your mouth. Your doctor, nurse or pharmacist can give you advice. It might help to try:
- sucking sugar-free sour or boiled sweets
- eating cold foods
- eating sharp-tasting fresh fruit.
Taste changes usually get better after treatment ends. We have more information about coping with changes to taste.
Effects on the heart
5FU can affect how the heart works. You may have tests to check how well your heart is working. These may be done before, during and after treatment.
You may develop heart problems even if these test results are normal. Very rarely, 5FU causes heart failure or a heart attack. The risk of this happening is very low. It happens to less than 1 in 100 (1%) of people who have 5FU. But it is important that you know about it.
Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:
- breathlessness
- dizziness
- changes to your heartbeat (palpitations)
- swollen feet and ankles.
Always call 999 if you have:
- chest pain, pressure, heaviness, tightness or squeezing across the chest
- difficulty breathing.
Effects on the lungs
This treatment can cause changes to the lungs. Tell your doctor, nurse or pharmacist if you develop:
- a cough that does not go away
- wheezing
- breathlessness.
You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs.
Effects on the kidneys and liver
This treatment can affect how your kidneys and liver work. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your kidneys and liver are working.
It is important to drink at least 2 litres (3½ pints) of fluids each day to help protect your kidneys.
Second cancer
Cyclophosphamide can increase the risk of developing a second cancer, years later. If a second cancer develops it is usually leukaemia.
But the benefits of treatment outweigh this risk. Your doctor can talk to you about this.
Other information
Blood clot risk
Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:
- throbbing pain or swelling in a leg or arm
- reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
- suddenly feeling breathless or coughing.
Always call 999 if you have:
- chest pain
- difficulty breathing.
A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.
Other medicines and food
Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:
- medicines you have been prescribed
- medicines you buy in a shop or chemist
- vitamins, herbal drugs and complementary therapies.
Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.
You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.
During treatment with cyclophosphamide you should avoid grapefruit and grapefruit juice as it may make side effects worse.
Vaccinations
Doctors usually recommend that people with cancer have vaccinations for flu and for coronavirus (covid). These help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.
If your immune system is weak, you should not have live vaccinations. Live vaccines can make you unwell because they contain a very weak version of the illness they will protect you against. Live vaccines include Zostavax®, which is a shingles vaccine, and the yellow fever vaccine.
It is important to ask your doctor, nurse or pharmacist for advice about having vaccinations. They can explain what vaccines are right for you and when it is best to have them.
Contraception
Your doctor, nurse or pharmacist will advise you not to get pregnant or make someone pregnant while having this treatment and for some time afterwards. The drugs may harm a developing baby. It is important to use contraception to prevent pregnancy. Follow their advice about:
- what types of contraception to use
- how long after treatment you should continue to use contraception.
Breastfeeding
You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk.
Your doctor, nurse or pharmacist can give you more information.
Fertility
Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.
Sex
It is possible that small amounts of chemotherapy may be passed on through vaginal fluids or semen. If you have sex during this treatment, your cancer team will usually advise using condoms or a dental dam to protect your partner.
Changes to periods
If you have a period, these may become irregular or stop while you are having this treatment. This may be temporary, but it can sometimes be permanent. Your menopause may start sooner than it would have done. Your doctor or nurse can give you more information.
Medical and dental treatment
If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.
If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.
About our information
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References
Visit the electronic Medicines Compendium (eMC) to download a Patient Information Leaflet (PIL) for more detailed information. The leaflet lists all known side effects.
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Reviewers
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.
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Date reviewed
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