Starting cancer treatment

This section has information about sex and relationships when you're starting treatment for cancer.

Young person about to start treatment

Talking to your healthcare team

When you are diagnosed with cancer, it can feel like everything happens very quickly. Your cancer doctor or specialist nurse may give you lots of information about cancer and treatments. You may have decisions to make.

It is important to get all the facts and support you need to make these decisions. This may include getting information about fertility and sex. You should also take time to think about what you want to do.

Cancer and fertility

Cancer and cancer treatments can affect your fertility (your ability to have children). Your cancer doctor or specialist nurse will talk to you about this before your treatment starts. They may offer you the chance to collect your eggs or sperm before you start cancer treatment. This is called fertility preservation. If you lose your fertility, you may be able to use the stored eggs or sperm to start a pregnancy.

You do not have to be in a relationship or know whether you want to be a parent to have fertility preservation. It just gives you options in the future. Your fertility may be something you have not thought about much before. You may come to terms with the situation quickly and feel that dealing with the cancer is more important. Or you may find you do not process what has happened until the treatment has finished.

Our website has a section on cancer and fertility for young people.  

Having sex during treatment

If you have sex during cancer treatment, it is important to prevent a pregnancy and protect yourself and any partners.

Preventing pregnancy 

Some cancer treatments can be harmful to an unborn baby. During treatment and for a time after, it is important to use contraception if you or a partner could become pregnant. Even if your cancer treatment is likely to damage your fertility, you may still be able to start a pregnancy. Your cancer doctor or specialist nurse can tell you more about this.

There are lots of different types of contraception. Ask your cancer doctor or specialist nurse which type is best for you to use. This will depend on you and the type of cancer treatment you are having. Condoms or caps (diaphragms) can be used whatever type of cancer treatment you have.

Some hormonal contraceptives (such as the pill, patch, injection or implants) may not work during cancer treatment. This can be because of:

  • the drugs you are taking
  • side effects, such as diarrhoea and vomiting.

Your doctor or nurse can tell you more about which types of contraception are safe for you to use.

Protecting partners

Small amounts of chemotherapy, or other drugs, can get into your body fluids. This includes fluid made in the vagina and the fluid that contains sperm. To protect any partners, your cancer doctor may advise that for a few days after taking certain drugs you:

  • use a condom for vaginal or anal sex
  • use a condom or a latex barrier such as a dental dam for oral sex.

Your cancer doctor or specialist nurse can give you more information about your treatment. If you use a lubricant, only use a silicon-based or water-based product with condoms or dental dams.

Protecting yourself

Using condoms and dental dams also helps protect you from sexually transmitted infections (STIs). This is especially important if your cancer treatment affects how your body fights infections. 

Again, if you use a lubricant, only use a silicon-based or water-based product with condoms or dental dams. 

You should also do the following:

  • Avoid giving oral sex if you have cuts or sores in your mouth. There is a risk these could become infected.
  • Tell your doctor if you notice any bleeding after sex. If the bleeding does not stop, contact a hospital straight away.
  • Use a condom and some silicon-based or water-based lubricant if you give or receive anal sex. This helps prevent bleeding or infection.
  • Never use the same condom for anal then vaginal or oral sex.
  • Clean sex toys, dildos or other objects before you use them, or cover them with a condom. If you use one for anal sex, clean it or change the condom before you use it for vaginal sex. If a partner uses it too, clean it or change the condom before you use it again.


Lubricants are gels or liquids that you can use before or during sex. Using lubricant can make penetration or sexual touching feel good. It can also make it feel easier and more comfortable.

Lubricants can be oil, silicon or water based. Always check the instructions to find out what type you are using. You should only use a silicon-based or water-based lubricant with a condom, dental dam, latex cap (diaphragm) and latex sex toys. Oil-based lubricant can make condoms, dental dams and latex caps tear and stop them working.

There are many brands of lubricant. Some products are available on the NHS. You can also buy lubricants from a pharmacy or other shops, or online.

Stopping periods (menstruation)

Some cancer treatments can affect the cells in the blood. This means that sometimes during or after treatment you may have:

  • a low level of red blood cells – these carry oxygen from the lungs to all the cells in the body
  • a low level of platelets – these help blood to clot and stop bleeding and bruising.

Your cancer doctor or specialist nurse may talk to you about taking tablets or injections to stop your monthly periods (menstruation). This stops you losing blood while your blood cell levels are recovering.

After your treatment and when your blood cell levels are better, you stop taking the tablets or injections. Your periods usually start again slowly.

Sex and the side effects of cancer treatment

Most people have some side effects during cancer treatment. Your cancer doctor or specialist nurse will explain what to expect.

Some side effects can change:

  • how you feel about your body
  • how you feel about sex
  • how you think other people feel about your body
  • how your body works during sex.

Side effects often get better after treatment. But some people find they have sexual problems for a longer time after treatment ends. If you find a side effect hard to cope with, try not to ignore it. You may feel embarrassed talking about it, but your healthcare team can help.

Not everyone will have the side effects we mention here. You may have side effects or questions we do not cover. You can always talk to your cancer doctor or specialist nurse about them.

Tiredness (fatigue)

During and after treatment, you might have less energy, need more rest or get tired more easily. When you are tired, you may be less interested in sex or even in spending time with other people.

If are with a partner, it might help to just spend time being close and intimate without planning to have sex. Sometimes this can lead to sex. But it is also a way to build trust and confidence together.

If you want to have sex or masturbate, choose a comfortable, relaxed position. You may want to plan for a time of day when you have more energy. Do not put pressure on yourself to make it last a long time or to orgasm (come).

Feeling sick

Some cancer treatments are more likely to cause sickness and nausea. This includes chemotherapy and some types of radiotherapy. Your cancer team will give you drugs to prevent sickness. Tell your doctor or nurse if you still feel sick, so they can help.

Your treatment may only make you feel sick at certain times. For example, chemotherapy is most likely to make you feel sick in the hours or days after you have it. If you can work out
a pattern, plan for times you are likely to feel more interested in sex.


Any type of pain can make you feel less interested in sex. You might not want to have sex because you feel uncomfortable. Or you might be worried that sex or masturbation will be painful. It can help to experiment. You may want to do this with a partner or by yourself first. Find out which positions or type of touching feels comfortable for you.

If you have a partner, it can help to talk about how you are feeling. They may not want to have sex if they are worried about hurting you. Try to find a position that feels comfortable and relaxed for you both.

You can also ask your cancer team or GP for advice about painkillers and ways to reduce the pain.

Problems with erections

Sometimes cancer treatment can cause problems with getting or keeping an erection. This is often a common response to what you are going through. It may happen because you are feeling tired or sick. Or it can happen because you are worried or coping with difficult feelings. It is often temporary and usually goes back to normal after treatment ends.

Some cancer treatments may also cause physical changes that make it difficult to get an erection. Your cancer doctor will explain if this is likely with your treatment. These changes include:

  • low levels of the hormone needed for erections (testosterone)
  • damage to the nerves or blood supply needed for erections.

Low testosterone

Some cancer treatments can affect your testosterone hormone levels. Hormones are chemicals in the body that help control how the body works. Low testosterone levels mean you are less likely to have erections or be interested in sex. If your testosterone level is low for a long time, this can also cause thinning of the bones (osteoporosis), tiredness and a low mood.

If your testosterone levels do not recover, you can take testosterone replacement therapy (TRT). You usually take this as a gel on your skin or as an injection. TRT can improve sex drive, erections, mood and tiredness. It also helps prevent long‑term problems, such as thinning of the bones.

Damage to the nerves and blood supply

Sometimes cancer, or cancer treatment to the pelvic area, can damage the nerves and blood supply to the penis and testicles. The pelvic area is the area between the hips and below the belly button. Damage to this area can cause problems with getting an erection or how you ejaculate.

There are treatments that may help if you are having erection problems. The treatment you can have will depend on exactly what is causing the problem. It is always best to ask your healthcare team for expert advice.

Early menopause

Some cancer treatments can affect female hormone levels. Your cancer doctor will explain if your treatment is likely to do this. Female hormones help control periods, fertility (being able to get pregnant and give birth) and how your body works during sex.

These hormone levels change naturally during the menopause (this usually happens between your mid‑40s and mid‑50s). When this happens, your periods slowly stop and you cannot get pregnant any more. You may also have symptoms such as:

  • hot flushes and sweats
  • vaginal dryness
  • loss of interest in sex
  • difficulty sleeping
  • weight gain
  • mood swings or loss of confidence.

If cancer treatment affects your hormone levels, you might have some of these symptoms. They may improve as your hormone levels recover after treatment.

If your hormone levels do not recover, you will have an early menopause. This is also called premature ovarian insufficiency (POI). You will not be able to get pregnant and you may keep having menopausal symptoms. Your cancer doctor or specialist nurse can talk to you about treatments that can help with these symptoms. They may also talk to you about treatment to replace the hormones that are at a low level. This also helps prevent long‑term problems such as thinning of the bones (osteoporosis) or heart disease.

It can be hard to cope with this when you are already coping with cancer. As well as coping with the symptoms, you may be dealing with some difficult feelings about losing your fertility.

Vaginal dryness

During sex, the vagina usually produces some natural fluid. Without this, sex may feel uncomfortable or painful. Vaginal dryness can happen during cancer treatment because you are tired, stressed or less interested in sex. It may also happen if your treatment has caused menopausal symptoms.

If you want to have sex, a lubricant may help with dryness. It can help make sex more comfortable. Lubricant is a gel or liquid that you can use inside the vagina. Your GP or cancer team can prescribe these products. You can also buy lubricants and moisturisers from a pharmacy or other shop, or online.

Vaginal changes

Cancer of the cervix or vagina may be treated with surgery or radiotherapy. Sometimes these treatments cause scarring or nerve damage. They can also make the vagina narrower and less stretchy. If this happens, you might find sex less comfortable, or find it harder to orgasm (come).

There are treatments that may help if you are having sexual problems, but it can depend on what is causing the problem. It is best to ask your healthcare team for advice if you are worried about any vaginal changes.