Managing Chemotherapy Side Effects: A Practical Guide

Why chemotherapy causes side effects

Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. According to the NHS, these drugs work by targeting cells that are dividing quickly. The problem is that some healthy parts of the body also have fast-dividing cells, such as the lining of the mouth and gut, the hair follicles and the bone marrow that makes blood cells. When chemotherapy affects these healthy cells too, it causes side effects.

The good news is that most side effects are temporary and gradually improve once treatment ends, as the healthy cells recover. Everyone reacts differently. The drugs used for breast cancer vary, so two people on different regimens may have very different experiences. Cancer Research UK explains that your team will tell you which side effects are most likely with your particular treatment.

This guide gives general, educational information. It is not personal medical advice, and your own treatment plan may be different. Always follow the advice of your chemotherapy team, and use the contact numbers they give you if you are worried.

Feeling sick and being sick (nausea)

Feeling sick (nausea) or being sick (vomiting) is one of the most common worries about chemotherapy. The reassuring news, according to the NHS, is that anti-sickness medicines (called anti-emetics) have become very effective. Your team will usually give you these to take before and after treatment to prevent sickness, rather than waiting for it to start.

It is important to take anti-sickness medicines exactly as prescribed, even on days when you feel well, because they work best when taken regularly to stop sickness building up. Cancer Research UK advises telling your team if the medicines are not controlling the sickness, as there are several different types and they can change or add to them.

Practical steps that many people find helpful include:

• Eat small amounts often rather than large meals, and eat slowly.
• Choose plain, bland foods such as toast, crackers or rice when you feel queasy.
• Sip cold or fizzy drinks slowly through the day to stay hydrated.
• Try ginger, for example in ginger tea or ginger biscuits, which some people find soothing.
• Avoid strong smells, very greasy or spicy food, and cooking when you feel sick.
• Get plenty of fresh air and rest, and loosen tight clothing around your waist.

Contact your team if you are sick more than once or twice in a day, cannot keep fluids or medicines down, or are unable to drink for several hours, as you may need a different anti-sickness medicine or fluids to stop you becoming dehydrated.

Hair loss and scalp cooling

Hair loss (alopecia) is a common and often distressing side effect, although not all chemotherapy drugs cause it. The NHS explains that whether you lose your hair, and how much, depends on the specific drugs you are given. Where it does happen, hair usually begins to fall out within two to three weeks of starting treatment, and this can include eyebrows, eyelashes and body hair.

Hair loss from chemotherapy is almost always temporary. Cancer Research UK notes that hair usually starts to grow back within a few weeks to months of treatment finishing, though it may come back a slightly different colour or texture at first.

Some people are offered scalp cooling (a cold cap) to try to reduce hair loss. The NHS explains that it works by cooling the scalp during treatment, which reduces blood flow and the amount of chemotherapy reaching the hair follicles. It does not work for everyone or with every drug, and you may still lose some hair, so ask your team whether it is suitable for you.

Ways to cope with hair loss include:

• Some people choose to cut their hair short, or shave it, before it falls out, to feel more in control.
• Use gentle, mild shampoo and avoid dyes, perms and heat styling while hair is fragile.
• Protect your scalp from the sun with a hat or sunscreen, and keep it warm in cold weather.
• Wigs are available, and the NHS may provide one free of charge in some circumstances, so ask your nurse.
• Scarves, headwraps and soft hats are comfortable alternatives many people prefer.

Sore mouth and mouth ulcers

Chemotherapy can affect the lining of your mouth, causing soreness, ulcers, a dry mouth or changes to how food tastes. Cancer Research UK explains that a sore mouth (mucositis) usually starts a few days after treatment and gets better as your blood counts recover. Looking after your mouth carefully can reduce the soreness and lower the risk of infection.

• Brush your teeth gently with a soft toothbrush, two to three times a day.
• Use any mouthwash your team recommends, but avoid mouthwashes containing alcohol, which can sting and dry the mouth.
• Rinse your mouth regularly, for example with a salt-water rinse if your team advises it.
• Sip water often and keep your lips moist with a lip balm to ease dryness.
• Choose soft, moist foods and avoid rough, salty, spicy or very hot foods that can irritate.
• Tell your team if you wear dentures, as a sore mouth may mean they need adjusting.

Let your team know if your mouth becomes very sore, if ulcers stop you eating or drinking, or if you notice white patches, which can be a sign of a treatable infection such as thrush. They can prescribe medicines to soothe the pain and clear infection.

Infection risk and neutropenia

This is the most important section to understand. Chemotherapy reduces the number of white blood cells your body makes, which are the cells that fight infection. When the level of a type of white cell called neutrophils is low, it is known as neutropenia. The NHS explains that this makes you more likely to pick up infections, and that an infection during this time can become serious very quickly.

A severe infection while your white cells are low is called neutropenic sepsis, and it is a medical emergency. The good news is that it is treatable when caught early, which is why acting fast really matters. Your team will give you a 24-hour contact number when you start chemotherapy. Keep it somewhere you can find it quickly, day or night.

Contact your chemotherapy team or 24-hour helpline straight away if you have any sign of infection, including:

• A high temperature. NHS and NICE guidance commonly advise calling urgently if your temperature goes above 37.5°C, and certainly if it reaches 38°C or higher, but always follow the exact threshold your own team gives you.
• A temperature below 36°C, or suddenly feeling cold, shivery or shaky.
• Feeling generally unwell, even with a normal temperature.
• Symptoms of infection such as a cough, sore throat, burning when you pass urine, or diarrhoea.
• Redness, swelling or pain anywhere, including around a line or port if you have one.

Do not wait to see if you feel better, and do not take paracetamol to bring a temperature down before you have spoken to your team, as it can mask a fever. Cancer Research UK advises keeping a thermometer at home so you can check your temperature if you feel unwell.

You can also lower your risk of infection between treatments. The NHS suggests washing your hands often, avoiding close contact with people who are unwell, keeping cuts clean and covered, and being careful with food hygiene. Ask your team about vaccinations, such as the flu jab, as their advice on timing during chemotherapy is important.

Tiredness and fatigue

Fatigue is one of the most common side effects of chemotherapy. It is more than ordinary tiredness: Cancer Research UK describes it as an overwhelming exhaustion that does not always go away with rest or sleep. It can build up over a course of treatment and may continue for some weeks or months after it ends, then gradually improve.

Fatigue can have several causes during chemotherapy, including the treatment itself, a low red blood cell count (anaemia), disturbed sleep, or low mood. Tell your team if you feel very tired, as some causes, such as anaemia, can be treated.

Practical ways to manage fatigue include:

• Plan your day around the times you usually have the most energy, and rest before you become exhausted.
• Break jobs into smaller steps, and accept offers of help with shopping, cooking or childcare.
• Stay gently active where you can. The NHS notes that light activity, such as a short walk, can actually boost energy.
• Eat well and drink enough fluids to support your energy levels.
• Keep a simple diary to spot patterns, so you can pace yourself across the week.

Balancing activity with rest is the key idea. Doing a little, often, tends to help more than long periods of complete rest. If fatigue is severe or stopping you doing everyday things, tell your team so they can check for treatable causes and arrange support.

Red-flag symptoms: when to get help urgently

While many side effects can be managed at home, some symptoms need urgent attention. Contact your chemotherapy team or 24-hour helpline straight away, day or night, if you have any of the following. If you cannot reach your team and feel very unwell, the NHS advises calling 111, or 999 in an emergency.

• A high temperature, or feeling cold, shivery and shaky, which may be a sign of infection.
• Feeling generally unwell or very weak, even without a temperature.
• Bleeding or bruising that does not stop, such as nosebleeds, bleeding gums or blood in your urine or stools.
• Severe or non-stop sickness or diarrhoea, or being unable to keep fluids down.
• Breathlessness, chest pain, a fast heartbeat or feeling dizzy.
• A very sore mouth or throat that stops you eating or drinking.
• A new rash, or sudden swelling, redness or pain, especially around a drip line or port.

Trust your instincts. Cancer Research UK and the NHS both stress that it is always better to call and check than to wait. Your team would far rather hear from you early than have you delay. Keep your 24-hour number, a thermometer and a list of your medicines somewhere easy to find.

Looking after yourself and getting support

Going through chemotherapy is demanding, both physically and emotionally. As well as managing the physical side effects, it is normal to feel anxious, low or overwhelmed at times. Talking to your team, your GP, or a support organisation can make a real difference. Free support lines, such as Macmillan Cancer Support on 0808 808 00 00, can offer information and a listening ear.

Remember that side effects are usually temporary, and your team has many ways to help you cope. Keeping a simple symptom diary, writing down questions before appointments, and accepting practical help from those around you can all ease the journey.

Good, clear information about treatment matters for everyone. Our charity works to improve early detection and access to support in underserved communities, where people may have less access to trusted guidance about what to expect from treatment and when to seek help. Spotting breast cancer early can sometimes mean less intensive treatment, which in turn can reduce the burden of side effects. If you have any concerns about your own treatment, your GP or chemotherapy team is always the right place to start.