Sex and Cancer: Radiotherapy

There are different types of radiotherapy: external beam radiotherapy, radioisotope therapy, and brachytherapy. Radiation is also used for some types of scans.

External beam radiotherapy

External beam radiotherapy is a type of radiotherapy that uses a machine to aim high-energy rays at the cancer from outside of the body. This is most commonly x-ray (photon) radiation but may also be particle radiation, for example proton beam therapy. 

If you are having external beam radiotherapy, it is generally considered safe to continue having sex. However, if you are having radiotherapy to the pelvis or lower abdomen, you may be advised to avoid sex during treatment and for several weeks afterwards to allow any inflammation and side effects to settle.

It is not uncommon for people with a penis to have a sharp pain when reaching climax and sometimes notice a bit of blood. This is because radiotherapy can irritate the tube that runs through the penis from the bladder (urethra). This should improve after the treatment finishes. Pelvic radiotherapy can also reduce the amount of semen (cum) you produce. You can ask your treatment team for more information tailored to your specific circumstance.

Other radiation exposures

Radioisotope therapy involves being injected with a radioactive substance. You may be advised to avoid sex in the first week following the injection and to use barrier contraception (e.g. condoms) throughout the treatment period and for several months afterwards. How long you will need to do this will depend on the type of radioactive substance being used. Ask your treatment team for more information.

Brachytherapy is a type of internal radiotherapy. It is used to treat many cancers including prostate, gynaecological, skin, and rectal. You may be advised to avoid sex during treatment and for several weeks afterwards to allow any inflammation and side effects to settle. Ask your treatment team for more information.

Some nuclear medicine scans and therapies will mean that you have residual radiation in your body for a period of time after the procedure. You may be given a set of restrictions to follow for a set period afterwards, including restrictions on sex or close contact with others to keep them safe from the radiation. The nuclear medicine team will give you specific information about this, and should be able to answer any questions you may have. As some of the radiation will be excreted through your urine, it is recommended that you refrain from urine play or ‘watersports’ for some time after the procedure. This time period will depend on the type of radioactive drug you have been given, and you should ask the nuclear medicine team for more specific advice.

Sore skin

Radiotherapy treatment to the pelvis can make skin externally and internally (e.g. the vulva and vagina or anus and rectum) very sore. You may feel like it is too uncomfortable to have sex if the skin over the area being treated has become red (like sunburn) or darkened and become sore. 

You need to be gentle with the affected area of skin whilst having treatment and for a few weeks afterwards in order to preserve the health of the skin and prevent skin damage which could lead to infections.

If you enjoy dressing up as part of your sexual activity, you may want to avoid having tight or textured clothing as well as any scented products or lubes over the sore skin to avoid further damage or irritation.

Radiation cystitis

Radiation cystitis is the term used to describe inflammation and scarring of the bladder lining caused by pelvic radiotherapy. 

It can make you feel like you need to pass urine (pee) more frequently and/or urgently and can cause pain or burning when you do so. Often the symptoms can get better but sometimes they can come back months or years later. When this happens, we call it chronic radiation cystitis.

Drinking plenty of fluids can help; cranberry juice is known to help with bladder problems but it is important to check that it won’t interact with any medication you are taking. Drinking strong coffee, tea and alcohol can make the symptoms worse. Let your clinical team know if you have symptoms as there may be medication they can give to help. Having penetrative sex when you have radiation cystitis is most likely something you would not want to do due to the discomfort and it would be best to wait till the symptoms have resolved. However there are other ways to enjoy sex and intimacy.

Anal sex

In prostate cancer, Permanent Seed Brachytherapy can sometimes be used. This procedure places radioactive seeds into the prostate that slowly release a low level of radiation into the area over a several months. If you enjoy being the bottom during anal sex there is a risk your partner could be exposed to radiation following treatment. It is therefore advisable to avoid receiving anal sex for 6 months after permanent seed brachytherapy. 

Although the seeds usually stay in the prostate it is possible for them to come out in your semen when you ejaculate. These instances are rare, but to be on the safe side, avoid sex for a few days after treatment, and use a condom the first five times you ejaculate. Dispose of used condoms safely in the bin.

If you are having radiotherapy to the rectum or anal canal, anal sex would not be advisable due to soreness and risk of bleeding. The effects of the radiotherapy will guide how long you should avoid anal sex for, but you can discuss this with your medical team if you’re not sure.

Radiotherapy to the groin and pelvis may cause a narrowing of the anal canal. This can make returning to receptive anal sex (bottoming) difficult or painful. If this has occurred, you may be offered dilation therapy but this will typically not reach a thickness similar to a penis. If you choose to purchase sex toys to continue dilation past what your cancer care team or GP can offer, remember to always buy toys with flared bases that are made from high quality materials. Professional sex shops, like ‘Sh!’ (see further resources section) may be able to provide tailored advice regarding sex toys for specific difficulties.

Vaginal sex

Prior to any radiotherapy treatment the radiographers will ask if there is any chance that you may be pregnant and they will advise you to inform them immediately if you were to become pregnant during treatment. You are advised against getting pregnant during radiotherapy and for at least 6 months after it has been completed.

Radiotherapy treatment to the pelvis can lead to the formation of scar tissue (known as fibrosis). This can lead to problems in the uterus (womb) making pregnancy difficult as the ability of the uterus to expand is reduced. It can also cause shortening or narrowing of the vagina. This can make sexual intercourse painful as the ability of the vagina to stretch is reduced. The amount of natural vaginal lubrication may also be reduced, causing dryness and thinning of the vaginal walls.

A number of these side effects can be prevented with good personal hygiene and the introduction of pelvic care such as dilation therapy and the use of vaginal moisturisers, lubes, and/or HRT. Your CNS or therapeutic radiographer will discuss this with you. 

If narrowing occurs, this can make returning to penetrative sex difficult or painful. Dilators try to prevent this narrowing from happening. If they have not been offered to you and you feel that you would benefit, raise this with your CNS,  doctor or therapeutic radiographer. Some people find that the dilators provided by their cancer care team are unappealing or uncomfortable. It is possible to replace dilators with sex toys of similar shape and size as long as they are high quality and able to be cleaned effectively. Vibrating toys can also encourage blood flow into clitoral, vulval and vaginal tissues and help the vaginal lubrication response.