Chemotherapy Side Effects


Chemotherapy is the most common treatment for a range of cancers and can significantly improve your chances of recovery. However despite this it is still an important decision to make and one that isn’t entirely straightforward as chemotherapy can in many cases have some unwanted side effects. It is not possible to predict precisely the side effects that you personally will experience as these differ from case to case. For some people there will be very few or even no side effects – but this is very rare.

How Does Chemotherapy Work?

To more fully understand the side effects of chemotherapy and why they occur it can be helpful to have a basic grasp of how the treatment works. To understand this it helps to understand how a cell reproduces. To reproduce a cell will go through ‘mitosis’ in which is splits in half to create two unique copies, however this process only lasts 30-60 minutes. The majority of a cell’s life cycle will be spent in the ‘G0 Phase’ which can also be referred to as the ‘resting phase’. This can last anywhere from a few hours to several years. After this the cell will move into the G1, S and G2 phase wherein it makes proteins, copies and checks the DNA ready to split. Chemotherapy drugs will then work by attacking cells that are in these various stages – generally the M phase and those building up to it. Different drugs will attack cells at different phases of their cycle and this is how doctors choose the best ones to use; but generally those in the resting phase will be left unharmed. Cancer is caused by the spread of damaged cells that have mutated DNA, and so to fight cancer it is a matter of destroying these cells before they take over too much of the body.

However in some cases of course there are casualties of war and healthy reproducing cells will also be attacked causing the vast range of symptoms that are associated with chemotherapy. It is up to doctors and patients to find a balance between the destruction of the cancer cells and the preservation of other healthy cells. This means that the areas that are affected are those with cells that naturally are intended to rapidly reproduce. This includes the hair follicles which explains hair loss, as well as the cells lining the stomach wall which explains why nausea, vomiting and fecal problems are also common.

Here we will list the common side effects of chemotherapy in more detail so that you may make an informed decision about whether you wish to go ahead with the treatment.

Note: While most of the side effects of chemotherapy are merely unpleasant or distressing, others can be potentially very dangerous if left unseen to. These include: shivering, breathing difficulties, high temperature, flu symptoms, bleeding from parts of the body that will not stop, mouth ulcers or diarrhea. If you suffer any of these symptoms then you should get immediate medical attention.

Likely Side Effects of Chemotherapy


This is a highly common effect of chemotherapy and occurs in the vast majority of cases. This can be general lethargy – consistent tiredness – or just difficulty continuing with regular tasks. When you are receiving chemotherapy it is important to ensure that you rest a lot and that you avoid strenuous activity that you don’t feel able to perform. It may be worth taking time off work. However that said, light moderate activity such as walking may help to increase energy levels.


This is another very common side effect that occurs in roughly 60% of cases. Fortunately if this is the case then you can be prescribed ‘anti-enemics’ which will help to prevent these symptoms. You should continue to take these even once the problem has cleared up to avoid the symptoms reoccurring. If the anti-enemics do not prevent the nausea then this may be a serious cause for concern and you should contact your doctors immediately.

Hair Loss

This is another common side effect and one that is best known – though it is not guaranteed. In some cases rather than losing hair you will simply find your hair becomes thin and brittle. When it does occur it tends to do so within the first few weeks of chemotherapy. It won’t necessarily effect the head though either and can also focus on the arms, legs, face, pubic area etc. This can be a very traumatic experience, but there are several ways you can manage it. Speak to your care team if you are struggling with hair loss and consider using wigs or other ways to counter the problem. You may also be able to limit your hair loss by using a ‘cold cap’ during treatment. This cold cap limits blood flow to the scalp and so reduces the amount of the dose that reaches the head. This will be effective in some but not all cases.


Chemotherapy decreases the number of white blood cells in the blood. The main role of these white blood cells is to fight infection, and so that will weaken your immune system and make you more prone to infection. It is important then to make sure that you take extra care in avoiding infection by maintaining good hygiene, avoiding those with infections such as the flu, and by trying not to cut or graze your skin – sterilize and protect the wound if you do.


Chemotherapy does not just lower white blood cells – it lowers red blood cell count too. These blood cells are responsible for carrying oxygen through the blood and so that means you end up feeling more lethargic still. You are also likely to find that your skin appears paler than usual. In severe cases you can feel shortness of breath and experience an irregular heartbeat. As the red blood cells are composed largely of iron, increasing the iron in your diet with supplementation or by eating nuts, beans, fruits, red meat and spinach etc can help combat this.


Chemotherapy additionally lowers platelets. These are the blood cells which normally clot excessive bleeding both external and internal. This means that wounds and cuts may not stop bleeding and that you might bruise very easily. If this becomes dangerous you may require a blood transfusion. It is of course important to avoid damaging your skin too.

Oral Mucositis

This is pain caused to the inside of the mouth alongside ulcers and tends to occur as a result of high-dose therapy usually after 10 days of chemotherapy. There are medications designed to reduce this symptom and fortunately it should clear up shortly after you finish your course.

Lack of Appetite

A reduced appetite is also a side effect of chemotherapy and this can of course be exacerbated by other symptoms such as nausea and ulcers. It is very important that you continue to eat and drink to give your body the energy, minerals and protein it needs to stay healthy. In serious cases you may need a nasogastric tube which can feed you while bypassing the mouth and throat by going through the nose.


You may find that your skin becomes dry and sore as a result of chemotherapy and this is worst in the extremities (the hands and feet). Your nails may also become flaky and brittle and you may be sensitive to sunlight. Avoid the sun to reduce this problem, make sure to use sun block, and moisturize regularly.


Chemotherapy can in some cases cause memory loss as well as difficulties with concentration. Often this is as a result of the fear and anxiety caused by other symptoms along with the fatigue.


Libido and fertility are often affected by chemotherapy. Apart from anything else your interest in sex can be diminished as a result of the other symptoms. In some cases depending on the type of therapy, chemotherapy may come with a risk of permanent infertility. If this possibility exists however, then your doctor will bring it to your attention before you undergo the treatment and it is then your decision to make – and you may still be able to conceive using other methods such as IVF (where women would have embryos frozen prior to the treatment and men would have a sperm sample taken). In most cases any loss of fertility will be temporary.


This tends to happen a few days after chemotherapy if it occurs. It is important that you inform your doctor in cases of diarrhea as this can lead to dehydration and malnutrition. There are medications which are able to prevent this problem.


Depression is a common side effect of chemotherapy – both directly as a result of the symptoms (lethargy and anemia) as well as a result of the stress caused by those symptoms. If you experience depression then this can exacerbate these symptoms too – leading to more tiredness and weakening the immune system. If you have depression as a result of your chemotherapy you should consider therapy or support groups.

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Gary Wickman

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Gary Wickman