What are late effects?

Most people have side effects during treatment for colon, rectal or anal cancer. Colon and rectal cancer are also sometimes called colorectal cancer. These are all types of bowel cancer. Usually, these side effects gradually improve over a few weeks or months after treatment has ended.

Sometimes side effects do not go away, or they start months or years after treatment has ended. These side effects are called:

  • long-term effects – if they begin during treatment, or shortly after treatment has ended, and last longer than 3 months
  • late effects – if they begin months or even years later, as a delayed response to treatment.

In this information, we use the term late effects to include both long-term and late effects of treatment.

Late effects of bowel cancer treatments

The most common late effect of bowel cancer treatment is a change in how the bowel works. Other common late effects include changes in how the bladder works or changes that may affect your sex life.

Sometimes late effects are more general, such as:

  • tiredness
  • pain
  • concentration problems.

Some late effects are more likely depending on the type of treatment and the area of bowel treated.

Related pages

Booklets and resources

Bowel changes

Most people have bowel changes after surgery or radiotherapy for bowel cancer. Your bowel habits may not go back to the way they were before treatment. But over time, bowel symptoms usually become less troublesome. Most people find they get into a new routine that becomes normal for them. This can take a year or more.

If you have ongoing bowel problems or symptoms, there are many things that can help. Your doctor or specialist nurse can give you advice about possible treatments and managing bowel problems.

Bowel changes after surgery

Different types of surgery may cause different bowel changes:

  • Surgery to remove a section of bowel

    Surgery for colon cancer or rectal cancer often involves removing a section of bowel affected by cancer. This makes the large bowel shorter than before. Bowel movements (stools) pass through more quickly. Stools may be softer and looser, or liquid (diarrhoea). You may have more frequent bowel movements and need to go to the toilet more often and more urgently. These changes often improve as your body adjusts in the 3 to 6 months after your operation.

  • Surgery to remove part of the rectum

    If part of the rectum was removed, there may be long-term changes in how your bowel works. The nerves and muscles that control bowel emptying may be affected. This may mean you cannot hold stools in your bowel as well as before. You may have less time to get to a toilet when you notice your bowel is ready to move. You may find it difficult to empty your bowel completely. Some people cannot tell the difference between wind or stool in their rectum.

  • Hernia after surgery

    Surgery may also weaken the muscles where the operation was done and increase your risk of developing a hernia in the future. A hernia is a bulge caused by a part of the inside of the body, such as the bowel, pushing through a weakness in the muscle or tissue wall.

  • Stoma

    If you had a stoma (an ileostomy or colostomy) made as part of your surgery, it can take some time to get used to it. You may have loose stools, or you may go between having loose stools (diarrhoea) and constipation. You may also be more aware of wind produced by the bowel. Some people find it difficult to tell when the stoma is going to be active. Our advice about coping with bowel control problems is usually also suitable for people with a stoma. We have included other information specific to coping with a stoma where we think this may be helpful.

  • Stoma reversal

    An operation to take away the stoma and re-join the bowel is called a stoma reversal. After this, it can take time for your bowel to get into a routine. It may take up to 2 years before your bowel is working normally again.

Bowel changes after radiotherapy

Pelvic radiotherapy often causes bowel changes. These usually get better within a few weeks of treatment ending. But some people have late effects that start months or years after treatment. Late effects caused by pelvic radiotherapy are sometimes called pelvic radiation disease (PRD). We have more information about possible late effects of pelvic radiotherapy.

Bladder changes

Treatment for bowel cancer may change the way the bladder works. It can also affect the muscles that support the bladder. Sometimes changes start during treatment and do not get better. Or they may develop months or years after treatment has finished.

Not all bladder changes are caused by cancer treatment. As you get older, the bladder and pelvic floor muscles naturally become weaker. Giving birth and going through the menopause can also affect these muscles.

If you have ongoing bladder problems or symptoms, there are many things that can help. Your doctor or specialist nurse can give you advice about possible treatments and managing bladder problems.

Bladder changes after surgery

Sometimes, surgery to the rectum causes long-term changes to the nerves that control the bladder. This can affect your bladder control. It may cause leaking urine (urinary incontinence). Or it may mean the bladder does not empty completely. Symptoms of bladder late effects after surgery include:

  • leaking urine (pee)
  • difficulty passing urine
  • straining to release urine
  • a delay in starting to pass urine
  • a weak stream of urine
  • repeated urine infections.

If you have any of these symptoms, it is important to get them checked. They can cause more serious problems if they are not treated.

Bladder changes after radiotherapy

Radiotherapy to the rectum often causes bladder changes. These usually get better within a few weeks. But some people have late effects that start months or years after treatment. Late effects caused by pelvic radiotherapy are sometimes called pelvic radiation disease (PRD).

We have more information about possible late effects of pelvic radiotherapy.

Effects on sex life

Bowel cancer and its treatment can affect your sex life. This can happen because of the physical, emotional and practical impacts of cancer and its treatment. Some treatments may change how your body and sex organs work during sex.

  • Changes in sexual sensation

    Radiotherapy or surgery for rectal or anal cancer can affect tissues and nerves in this area. You may find sex feels different or that it is harder to get aroused or orgasm.

  • Vaginal changes

    Surgery or radiotherapy for rectal or anal cancer may make the vagina shorter or narrower. Pelvic radiotherapy can also cause vaginal dryness and make the vagina less stretchy. The walls of the vagina may be more fragile and likely to bleed. We have more information about coping with vaginal changes.

  • Menopausal changes

    Treatments such as chemotherapy and pelvic radiotherapy can affect the ovaries and cause an earlier menopause. This can cause symptoms that make sex difficult, such as vaginal dryness or low sex drive. We have more information about coping with menopausal symptoms.

  • Erection problems

    Surgery or radiotherapy for rectal or anal cancer can affect the nerves and blood vessels that supply the penis. This can make it difficult to get and keep an erection. If erection problems develop after radiotherapy, this usually happens slowly, a few months after treatment. It may continue getting worse for up to 3 years. If you have problems getting or keeping an erection (erectile dysfunction), there are treatments that may help.

  • Low testosterone levels

    Radiotherapy for rectal or anal cancer may affect the testicles and cause low levels of the hormone testosterone. This can cause a low sex drive and erection problems. Your doctor can tell you if testosterone replacement therapy might helpful for you.

  • Anal or rectal changes

    Changes to the anus or rectum can be caused by surgery or radiotherapy for rectal or anal cancer. This may affect your sex life if you receive anal sex. It is important to ask your doctor or nurse for advice. They can explain what to expect and if it is safe for you to receive anal sex. Sometimes changes can mean anal sex is no longer possible. A sex therapist may be able to help you cope and find different ways to enjoy sex.

  • If you have a stoma

    Having a stoma can affect your confidence and the way you feel about your body. Sex will not harm the stoma, but it can make some positions uncomfortable. We have more information about coping with a stoma and sex.

Many changes caused by cancer treatment are temporary and usually get better after treatment. But if your sexual well-being is affected after treatment, try not to let embarrassment stop you from asking for help. Your healthcare team are used to talking about sex. There may be advice, support or treatments that can help. If needed, they may be able to refer you to a specialist.


Tiredness (fatigue) is a very common side effect of cancer treatment. You may get tired more quickly after less activity and find that resting often does not help.

For most people, fatigue gets better after treatment finishes. But for some it may continue for months or sometimes years.

It is important to tell your doctors and nurses about your fatigue and how it makes you feel. Be honest and do not say you feel fine if you do not. There may be things they can do to help. For example, they can help treat the causes of fatigue, such as pain or difficulty sleeping.

Concentration and memory problems

After cancer treatment, some people notice changes in memory or concentration and their ability to think clearly. This is often called cancer‑related cognitive changes (CRCC) or chemo brain. But changes in memory and concentration can also affect people who have not had chemotherapy.

Changes in memory or concentration are usually mild. They often get better within a year of finishing treatment. But they can sometimes last longer or have more of an impact on your daily life.

Common symptoms include:

  • being unusually disorganised
  • getting distracted more easily
  • finding it hard to remember things
  • feeling like you cannot think clearly.

Tell your doctor or nurse if you notice changes in your memory or ability to concentrate. They can give you more information and support.

Damage to nerves after chemotherapy

Damage to nerves that supply the hands, legs and feet is called peripheral neuropathy. The chemotherapy drug oxaliplatin is the most common cause of peripheral neuropathy in people who have had treatment for bowel cancer.

Nerves carry messages between the brain, the spinal cord and the rest of the body. Nerve damage affecting the hands and feet causes symptoms such as:

  • pins and needles
  • numbness
  • weakness
  • pain.

For a few people, this may cause problems with balance and walking.

After chemotherapy, symptoms often improve as the nerves slowly recover. This usually takes several months. For some people, the nerves do not completely recover and some nerve damage never goes away.

It is important to tell your doctor or nurse if you have any of these symptoms. The symptoms often become less troublesome over time as you find ways of coping with the changes. But some people may need drugs or other treatments.

Getting help with late effects

Some late effects may not affect your daily life very much. Others can be more difficult to live with and they may affect your quality of life. Help and support is available, and there are usually things that can help you cope.

Talk to your cancer doctor or specialist nurse if you have:

  • side effects that do not go away
  • new symptoms or problems after treatment has ended.

You can arrange to see your cancer doctor or specialist nurse in between follow up appointments if needed. You can also contact your GP.

The more you tell your healthcare team, the more they may be able to help you. Some problems may feel embarrassing to talk about. But try not to let that stop you getting advice. Doctors and nurses are used to speaking about these issues and it is important that you get the right information and support.

Other types of expert help

Some people with late effects need help from other specialists. Your doctor or nurse can refer you to a specialist if needed. For example:

  • A gastroenterologist – a doctor who treats problems with the digestive system.
  • A colorectal surgeon – a doctor who does operations (surgery) on the large bowel.
  • A urologist – a doctor who treats problems with the kidneys, bladder and male reproductive system.
  • A gynaecologist – a doctor who treats problems with the female reproductive system.
  • A continence adviser – a specialist nurse or physiotherapist who gives advice and support to people with continence problems.
  • A doctor or nurse who treats late effects.

A few hospitals have clinics for people with late effects. Ask your healthcare team whether there are any near you. The Pelvic Radiation Disease Association may also be able to help you contact specialists.

Other support

After having cancer, it is natural for your body to feel different, and for you to feel differently about your body. If you are worried about symptoms or are struggling with your emotions , tell your doctor or specialist nurse as soon as possible. You do not have to wait until your next check-up to contact your doctor or any other health professional.

You can talk to other people facing similar challenges by joining a support group or by using social networking sites. You could join the radiotherapy and side effects forum or another forum on our Online Community. Your specialist nurse will have details of cancer support groups and counselling services in your area. Or you can call us on 0808 808 00 00 to speak to one of our cancer support specialists. They will be able to help you find support, or they can just listen.

Work and money

If you have late effects after cancer treatment, this may make working more difficult. Some people may decide to change the type of work they do or the way they work. Others may not be able to work anymore because of the effects of cancer on their health.

If you have to stop working you might need financial support. Or you might have extra costs because you have late effects.

We have more information about work and money that you may find helpful. Or call our financial guides on 0808 808 00 00.

About our information

  • References

    Below is a sample of the sources used in our late effects of bowel cancer treatment information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Andreyev HJN, Muls AC, Norton C, et al. Guidance: The practical management of the gastrointestinal symptoms of pelvic radiation disease. Frontline Gastroenterology, 2015; 6, 53-72. 

    NICE. Faecal incontinence in adults: management (CG49). (Internet), 2007. Available from www.nice.org.uk/guidance/CG49 (accessed January 2021).

    NICE. Lower urinary tract symptoms in men: management (CG97). (Internet), 2015. Available from www.nice.org.uk/guidance/cg97 (accessed January 2021).

    NICE. Urinary incontinence and pelvic organ prolapse in women: management (NG123). (Internet), 2019. Available from www.nice.org.uk/guidance/ng123 (accessed January 2021).

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 July 2021
Next review: 01 July 2024
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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