Infection and cancer

If you are on cancer treatment, you'll be advised to look out for signs of infection.

Infection can be a serious side effect of cancer treatment. Treatments designed to destroy cancer cells can also lower the level of infection-fighting white blood cells (neutrophils) in your body. This means you are more at risk of picking up a bug (viral or bacterial infection).

During and after cancer treatment, an infection can become serious and even life threatening very quickly.  A less serious infection may still require medical treatment and cause delays with your treatment plan.

It's important to recognise the signs of infection and report them promptly to your healthcare team, so that you can be assessed quickly, and treatment started.

Cancer and infections - what’s the connection?

Neutrophils (a type of white blood cell) are made in the body by the bone marrow. Chemotherapy drugs and some radiotherapy treatments can damage your bone marrow. 

Your risk of infection increases if your neutrophil count falls below normal. Neutrophils in the blood are measured as part of a full blood count test (FBC).

When neutrophils are low this is called neutropenia.

The type or dose of chemotherapy you are having may increase your risk of developing neutropenia. You're more at risk if you:

• already have low white blood counts
• have another condition that affects the immune system
• are over 65
• have previously received chemotherapy or radiotherapy.

There are certain times during each cycle of a course of treatment where the bone marrow, which produces the white blood cells, is most affected .

This usually starts around a week after treatment. It lasts until the bone marrow gradually recovers - about 3-4 weeks after treatment . Your specialist nurse/doctor will let you know about the effects of your particular treatment.

How you are monitored during treatment

You'll be at risk of infection for as long as your neutrophil count is low. You may feel particularly tired, and also low in mood, during this time as well.

Your blood count is checked regularly throughout your course of treatment. If your neutrophil count is low your chemotherapy may be delayed to allow neutrophil counts to recover.

Often a week's delay is enough but sometimes the dose of chemotherapy is reduced to allow treatments to continue safely.

If you do develop an infection you'll usually have a blood test and be treated with antibiotics. In some cases admission to hospital for stronger intravenous (via a drip or a syringe into a vein) antibiotics may be necessary.

Not all infections can be prevented. However, reporting any signs of infection early to your healthcare team will allow you to have prompt treatment and will reduce the risk of serious problems.

Managing infections

There are three main things to remember:

• Recognise signs of infection
• Report any promptly
• Prevent infections occurring where you can.

 Recognise the symptoms (signs) of infection

Knowing what to look out for can be reassuring for you and also those around you. Ask your specialist nurse/doctor what to expect after each course of treatment.

• Fever (high temperature): This is the body’s natural response against invaders such as viruses, bacteria and fungus and is often one the first symptoms of infection.
• Take your temperature if you feel unwell. Your healthcare team will give you instructions about the level your temperature should reach. Generally, if it's higher than 38⁰C (100.4F) you should call your healthcare team immediately (day or night) because it could mean you have an infection.  

Whilst fever is a common sign of infection it is not always present. Some medication can mask or hide a fever. Other signs of infection which you should also report straight away include:

• Chills, shivers, shaking, sweating
• Cough, sore throat, shortness of breath, chest pain
• Redness, warm skin, pain, swelling or oozing around any wounds or catheter sites (where a cannula, PICC line, Hickman line or other central line has been used)
• Loose bowels or diarrhoea for more than 24 hours
• Pain in the back above the waist or burning sensation when passing urine
• Mouth ulcers, furry tongue
• Unusual vaginal discharge or itching.

Report signs of infection promptly. Whilst you are on cancer treatment, you'll have detailed instructions of symptoms to look out for by your medical team.  You'll be given the number to call out of hours if you develop them and you should follow these instructions carefully. 

Remember infections can get worse much quicker than normal and can become serious if you delay.

It's far better to phone and check your symptoms with your hospital team,  day or night, rather than waiting to see if symptoms improve. 

If you are telling a different doctor or team, or are having to go to an emergency department you should emphasise that you are having treatment for cancer -  this will highlight the need for you to be treated quickly.

Preventing infection where you can

Many infections during or after cancer treatment are not caught from other people but are from normal bacteria (flora) within your gut or skin. 

• Wash your hands and get those around you to wash theirs.  This is the most important way to avoid the spread of infection causing bacteria.
• Wash your hands often and with extra care before eating, and before and after bathroom use or stroking pets.
• Take the time to scrub your hands thoroughly with soap and warm water.  It’s the friction that kills bacteria.
• Take your temperature as recommended by your healthcare team and call your healthcare team immediately (day or night) if your temperature is higher than 100.40F or 38 ⁰C.
• To avoid getting a urinary tract infection, wipe your bottom thoroughly after each bowel movement. Wipe gently from front to back.
• Have a warm bath or shower every day and pat your skin dry.
• Use a water based lotion if your skin becomes dry.
• Use an electric shaver instead of a razor.
• Warm soapy water and antiseptic will clean cuts and scrapes. (Seek specific skincare advice if you are having radiotherapy.) 
• Mouth care: follow any specific mouth care advice you are given by your healthcare team but, in general, brush your teeth twice a day with a soft toothbrush. Check with your healthcare team if it is ok to floss.
• Food: make sure that all foods are properly handled, stored, used within expiry dates and thoroughly cooked. Wash fresh fruit and vegetables before eating. Ask your healthcare team if there are any specific foods you should to avoid.
• Wear protective gloves when gardening or cleaning up after pets.
• If you have any dressings/bandages over surgical wounds make sure they are clean and dry. 

If your chemotherapy treatment is known to cause neutropenia your healthcare team may recommend treatment with medicine called growth factors. These stimulate the bone marrow to produce white blood cells and help prevent infection.

They're not used routinely for all people receiving cancer treatment. They're not suitable for all treatments and can have side effects of their own (bone pain, fatigue, fever and appetite loss).

Things to avoid when your counts are low

• Crowds and people with infections, infectious illnesses eg chickenpox or heavy colds.
• Eating soft cheeses, pate, pro- biotic drinks or pro-biotic yoghurts.
• Vaccinations unless you check first with you healthcare team.
• Aspirin or other medication to reduce fever unless you check first with your healthcare team.
• Dusty areas or places where there is digging/building work taking place.
• Situations where you may bruise or break your skin.

Having an infection or a low neutrophil count may mean your treatment may be delayed. You may have your chemotherapy dose reduced.

Not all infections can be prevented. However, looking after yourself, and reporting problems early is helpful. It means you can have an infection treated promptly, and help avoid delays in treatment.

What now?

Talk to your specialist nurse/doctor. Find out whether your cancer treatment is likely to raise your risk of infection and any special precautions you need to take. Tell them promptly about any side effects you have following treatment. 

Have a read through the links to blogs and information we have suggested on this page.

Drop into your nearest Maggie's centre to talk things over with other visitors and our cancer support specialists. Ask about our courses and workshops which can help you through your treatment and beyond.

Last review: Feb 2022 | Next review: Feb 2023