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Side effects of chemoradiotherapy

Most people will have some side effects from chemoradiotherapy for cancer of the back passage (rectum). See what side effects you might have and how to cope with them.

The side effects vary from person to person. You might not have all of the effects mentioned. Side effects depend on the type of chemotherapy you have. They also depend on the radiotherapy treatment area.

The side effects gradually get worse during the treatment. They can continue to get worse after your treatment ends. But most of the effects begin to improve after 1 or 2 weeks.

Contact your advice line or your doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

Tests

You have blood tests before 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.

Common side effects

These effects happen in more than 1 out of 10 people.

Signs of an infection include headaches, aching muscles, a cough, a sore throat, pain passing urine, or feeling cold and shivery.

Contact your advice line or doctor straight away if you have any of these signs, or your temperature goes above 37.5C or below 36C. Severe infections can be life threatening.

Chemotherapy reduces the number of white blood cells in the blood. This increases your risk of infections. White blood cells help fight infections.

When the level is very low it is called neutropenia (pronounced new-troh-pee-nee-ah).

You have antibiotics if you develop an infection. You might have them as tablets or as injections into the bloodstream (intravenously). To have them into your bloodstream you need to go into hospital.

Chemotherapy makes the level of red blood cells fall (anaemia). Red blood cells contain haemoglobin, which carries oxygen around the body. When the level of red blood cells is low you have less oxygen going to your cells. This can make you breathless and look pale. Tell your doctor or nurse if you feel breathless.

You have regular blood tests to check your red blood cell levels. You might need a blood transfusion if the level is very low. After a transfusion, you will be less breathless and less pale.

You can also feel tired and depressed when your blood count is low and feel better once it is back to normal. The levels can rise and fall during your treatment. So it can feel like you are on an emotional and physical roller coaster.

You might notice you:

  • bruise more easily
  • have nosebleeds
  • have bleeding gums when you brush your teeth

This is due to a drop in the number of platelets that help clot your blood.

If your platelets get very low you may have lots of tiny red spots or bruises on your arms or legs called petechiae.

Tell your doctor or nurse straight away if you have petechiae.

You have a platelet transfusion if your platelet count is very low. It is a drip of a clear fluid containing platelets. It takes about 15 to 30 minutes. The new platelets start to work right away. 

You might feel tired during your treatment. It tends to get worse as the treatment goes on. You might also feel weak and lack energy. Rest when you need to.

Tiredness can carry on for some weeks after the treatment has ended but it usually improves gradually.

Various things can help you to reduce tiredness and cope with it, such as exercise. Some research has shown that taking gentle exercise can give you more energy. It's important to balance exercise with resting.

Feeling sick might be constant. It may be worse a few hours after chemotherapy treatment and you may be sick. Anti sickness injections and tablets can control it. Tell your doctor or nurse if you feel sick. You might need to try different anti sickness medicines to find one that works.

Tips 

  • Avoid eating or preparing food when you feel sick.
  • Avoid hot fried foods, fatty foods or foods with a strong smell.
  • Eat several small meals and snacks each day.
  • Relaxation techniques help control sickness for some people.
  • Ginger can help – try it as crystallised stem ginger, ginger tea or ginger ale.
  • Try fizzy drinks.
  • Sip high calorie drinks if you can’t eat.

Your mouth might become sore about 5 to 10 days after you start treatment. It usually clears up gradually 3 to 4 weeks after your treatment ends.

Your doctor or nurse can give you mouthwashes to help prevent infection. You have to use these regularly to get the most protection.

Tell your doctor or nurse straight away if your mouth is really sore. They can help to reduce the discomfort. Some people need strong painkillers to help control mouth pain so they can eat and drink.

Tips

  • Clean your mouth and teeth gently every morning and evening and after each meal.
  • Use mouthwashes as advised by your doctor or nurse. Let them know if the mouthwash stings. They can tell you to stop using it or dilute it with water.
  • Use dental floss daily but be gentle so that you don't harm your gums, and don't floss if you have very low platelets.
  • Avoid neat spirits, tobacco, hot spices, garlic, onion, vinegar and salty food.
  • Moisten meals with gravies and sauces to make swallowing easier.
  • Avoid acidic fruits such as oranges, grapefruit or lemons.

Tell your doctor or nurse if you have diarrhoea. Drink at least 2.5 litres of fluid a day to help keep you hydrated. Let your doctor or nurse know straight away if the diarrhoea is severe or getting worse.

Ask your nurse about soothing creams to apply around your back passage (anus). The skin in that area can get very sore.

Heart problems include changes to how your heart works. This can cause changes to your heart rhythm and your ankles can swell.

Tell your doctor or nurse straight away if you have any chest pain. Your doctor might ask you to have tests to check your heart, such as an electrocardiogram (ECG).

The skin on your hands and feet can become sore, red, and peel. You might also have tingling, numbness, pain and dryness. This is called hand-foot syndrome or palmar plantar syndrome.

Tell your doctor or nurse straight away if you have pain, swelling, redness or tingling of your hands or feet.

Tips

  • Take medicines that your doctor or nurse can prescribe.
  • Keep your hands and feet cool.
  • Avoid very hot water.
  • Don’t wear tight fitting gloves or socks.
  • Moisturise your skin with non perfumed creams.

Your hair may thin. It usually begins falling out gradually within 2 to 3 weeks after treatment starts.

Your hair grows back once your treatment has finished. This can take several months and your hair is likely to be softer.

Tips

  • Use gentle hair products such as baby shampoos.
  • Don't use perms or hair colours on thinning hair.
  • Use a soft baby brush and comb thinning hair gently.
  • Pat your hair dry gently rather than rubbing.
  • Avoid using hair dryers, curling tongs and curlers.

High levels of uric acid in your blood can lead to a build up of crystals in body tissues and cause inflamed joints. You’ll have regular blood tests to check your levels. Drinking plenty of fluids helps to flush out the excess uric acid. You might also have medicines to control the uric acid levels.

Occasional side effects

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

Your nails can have a blue tinge or become darker. Or they might flake, be painful and thicken where the nail starts growing (the nail bed).

Tips

  • Use nail oils or moisturising creams if your nails are flaking.
  • Don't worry about marks on your nails as they will grow out in time.
  • You can cover marked nails with nail varnish but avoid quick drying varnishes as they can make your nails even drier.

Don't use sunbeds or sit in the sun. Cover up or use sunscreen if you go out in the sun. 

Remember to put sun cream on your head or wear a hat if you have lost hair there.

Skin changes include darker skin and rashes, which may be itchy.

Tell your doctor if you have any rashes or itching. Don't go swimming if you have a rash because the chlorine in the water can make it worse.

If your skin gets dry or itchy, smoothing in unperfumed moisturising cream may help. Check with your doctor or nurse before using any creams or lotions. Wear a high factor sun block if you’re going out in the sun.

Watery eyes is also called excessive tearing or epiphora (pronounced ep-if-or-ah). It may be due to a blockage in the drainage system of the eye, caused by swelling of the nearby tissues. Or your eyes may make too many tears.

Tell your doctor or nurse if this is a problem. They can prescribe medicines to help reduce swelling.

Some irritants can make the watering worse. These can include dust, pollen or animal hairs. Try to avoid them or wear protective goggles.

Your eyes may be sore because the drugs cause a reaction on the inside of your eyelids. Or you may not be making enough tears. Your eyes can feel sore and gritty and might be red.

Tell your doctor or nurse if you have dry eyes. They can prescribe eye drops, ointments or artificial tears for you.

Warm compresses can help your eye to drain if you have an infection.

A brown marking on the skin following the line of the vein where fluorouracil has been injected can appear. This usually fades over time. Speak to your doctor or nurse if you are worried about this.

Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Men

You may be able to store sperm before starting treatment.

It can take a few months or sometimes years for fertility to return to normal. You can have sperm counts to check your fertility when your treatment is over. Ask your doctor about it.

Women

Chemotherapy can cause an early menopause. This stops you from being able to become pregnant in the future. Talk to your doctor about this before your treatment. It’s sometimes possible to store eggs or embryos before treatment.

Constipation is easier to sort out if you treat it early. Drink plenty of fluids and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking.

Tell your doctor or nurse if you are constipated for more than 3 days. They can prescribe a laxative.

Let your doctor or nurse know if you have headaches. They can give you painkillers. Don’t drive or operate machinery if you feel dizzy.

Tell your doctor or nurse if you have this.

You might lose your appetite for various reasons when you are having cancer treatment. Sickness, taste changes or tiredness can all put you off food and drinks.

Tips

  • Eating several small meals and snacks throughout the day can be easier to manage.
  • Ask your doctor or nurse to recommend high calorie drinks to sip between treatments, if you are worried about losing weight.
  • You can make up calories between treatments for the days when you really don’t feel like eating.
  • Drink plenty of fluids even if you can't eat.
  • Don't fill your stomach with a large amount of liquid before eating.
  • Try to eat high calorie foods to keep your weight up.

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.

Women might stop having periods (amenorrhoea) but this may be temporary. This is a side effect from the chemotherapy only. 

Rare side effects

Fewer than 1 in 100 people have these effects.

You could lose all your hair. This includes your eyelashes, eyebrows, underarm, leg and sometimes pubic hair. It usually starts gradually within 2 to 3 weeks after treatment begins.

Your hair will grow back once your chemotherapy treatment has finished. This can take several months and your hair is likely to be softer. It can also grow back a different colour or be curlier than before.

Tips

  • Ask about getting a wig before you start treatment so you can match the colour and texture of your real hair.
  • You could choose a wig for a whole new look.
  • Think about having your hair cut short before your treatment starts.
  • Some people shave their hair off completely so they don't have to cope with their hair falling out.
  • Wear a hairnet at night so you won't wake up with hair all over your pillow.

You might feel confused or unsteady. This usually stops when you finish treatment.

Changes to your eyes get better when you stop treatment.

Make sure you drink at least 2 litres of fluid a day and let your doctor or nurse know if you feel dizzy or faint.

It can help to warn your family that you might get this. You or your family members should let your doctor or nurse know if you have it. 

Numbness or tingling in fingers and toes can make it difficult to do fiddly things such as doing up buttons. This starts within a few days or weeks and can last for a few months. Rarely, the numbness may be permanent.

Tips

  • Keep your hands and feet warm.
  • Wear well fitting, protective shoes.
  • Take care when using hot water as you may not be able to feel how hot it is and could burn yourself.
  • Use oven gloves when cooking and protective gloves when gardening.
  • Moisturise your skin at least a couple of times a day.
  • Take care when cutting your nails.

Your skin may become lighter or darker when you are having treatment but this goes back to normal when you finish.

A severe skin reaction that may start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish and your eyes may be more sensitive to light. This is serious and could be life threatening

DPD deficiency

Between 2 and 8 out of 100 people (2 to 8%) have low levels of an enzyme called 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.

Low DPD levels don’t cause symptoms so you won’t know if you have a deficiency. You should have a test before you start this treatment to check if you have a DPD deficiency. 

Some people have severe side effects from capecitabine or fluorouracil even if they don't have low DPD levels. Contact your doctor or nurse if your side effects are severe.

Long term side effects

Most side effects gradually go away in the weeks or months after treatment. However, some side effects can continue or might start some months or years later. 

Last reviewed: 
15 Oct 2018
  • Electronic Medicines Compendium
    Accessed October 2018

  • Rectal cancer: ESMO Clinical Practical Guidelines for diagnosis, treatment and follow up
    R Glynne-Jones and others
    Annals of Oncology, 2017. Volume 28, Pages 422-440