Late effects of bowel cancer treatment
You may have side effects that start or last some time after you finish treatment for bowel cancer (this includes colon, rectal and anal cancer).
What are late effects?
Most people have side effects during treatment for colon, rectal or anal cancer (bowel cancer). Usually, these side effects 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 mean both long term and late effects.
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 (colon, rectal or anal cancer). Your bowel habits may not go back to the way they were before treatment. But over time, bowel symptoms usually become easier to live with. Many people find they get into a new routine that becomes normal for them. This can take 1 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.
Changes after surgery
Different types of surgery may cause different bowel changes:
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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 (stool) will pass through more quickly. Stool (poo) may be softer and looser, or liquid. You may go to the toilet more often and need to go more urgently.
These changes often improve as your body adjusts in the 3 to 6 months after your operation.
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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 and stool in their rectum.
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Hernia after surgery
Surgery may also weaken the muscles where you had the operation. This may 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 the muscle or tissue wall.
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Stoma
A stoma (colostomy or ileostomy) is an opening made during surgery. It connects the bowel to the surface of the tummy.
If you had a stoma made as part of your surgery, it can take some time to get used to it. You may have loose stools, or you may switch between having loose stools and constipation. You may also be more aware of wind produced by the bowel.
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.
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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.
We have more information about managing bowel problems.
Changes after radiotherapy
Pelvic radiotherapy often causes bowel symptoms. These usually get better within a few weeks after treatment ends. 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 the late effects of pelvic radiotherapy.
Bladder changes
Treatment for bowel cancer may change how 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 (late effects).
Not all bladder symptoms 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, certain things can help. Your GP or cancer team can give you advice about possible treatments and managing bladder problems.
Changes after surgery
Sometimes surgery to the rectum (back passage) causes long term changes to the nerves that control the bladder. This can affect your bladder control and make it difficult to hold in urine (pee). This is called urinary incontinence. Or you may find the bladder does not empty completely after surgery.
Symptoms of bladder late effects after surgery include:
- urinary incontinence (leakage)
- difficulty passing urine (peeing)
- 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.
Changes after radiotherapy
Radiotherapy to the rectum often causes bladder side effects. These usually get better within a few weeks. But some people have side 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 your sex life
Bowel cancer and its treatment can affect your sex life. This can happen because of the physical, emotional and practical effects of cancer and its treatment.
Some treatments may change how your body and sex organs work during sex.
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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.
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Vaginal changes
Surgery or radiotherapy for rectal or anal cancer may make the vagina shorter or narrower. Pelvic radiotherapy can also make the vagina drier and less stretchy. The walls of the vagina may be more fragile and likely to bleed.
We have more information about coping with vaginal changes.
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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 a dry vagina or low libido (sex drive).
We have more information about coping with menopausal symptoms.
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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. Erection problems may develop after radiotherapy. But this usually happens slowly, a few months after treatment. It may continue getting worse for up to 3 years.
f you have problems getting or keeping an erection, there are treatments that may help.
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Low testosterone levels
Radiotherapy for rectal or anal cancer may affect the testicles and cause low levels of the male hormone testosterone. This can cause a low libido and erection problems.
Your doctor can tell you whether testosterone replacement therapy might be helpful for you.
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Anal or rectal changes
Surgery or radiotherapy for rectal or anal cancer may affect your sex life if you receive anal sex. It is important to ask your doctor or nurse for advice. Sometimes changes can mean anal sex is no longer possible.
A sex therapist may be able to help you cope with any of these changes and help you find different ways to enjoy sex.
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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. Choose positions that avoid putting weight on the stoma.
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 treatment affects your sexual wellbeing, 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 specialists.
If you identify as LGBTQ+, your healthcare team are there to support you and treat you in a way you feel comfortable with. The impact of cancer and cancer treatment are often the same whatever your sexual orientation or gender. But you may have some specific questions about any effects on your sexual well-being.
Tiredness
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 tell them you feel fine if you are not feeling well. 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 1 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 specialist nurse if you have any of these symptoms. The symptoms often improve as you find ways of coping with the changes. But some people may need drugs or other treatments to help.
Getting help with late effects
At your hospital follow-up appointments, your specialist will assess your late effects and how they are being managed. They will also check that there are no signs of the cancer coming back.
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 appointments if needed. You can also contact your GP.
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 sex therapist – someone who gives information and support to people with sexual 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.
Work and money
If you have late effects after cancer treatment, you may find 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 may need support with money. Or you may need help with extra costs because of late effects. We have more information about work and money that you may find helpful.
Our expert money advisers can help you deal with money worries, provide information about benefits and recommend other useful organisations that can help. Call us for free on 0808 808 00 00.
Other ways to support
After cancer or cancer treatment, it is normal 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.
- Join the radiotherapy and side effects forum or another forum on our Online Community.
- Chat to your specialist nurse for details of cancer support groups and counselling services in your area.
- Call the Macmillan Support Line for free on 0808 808 00 00 to speak to one of our cancer support specialists.
About our information
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.
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References
Below is a sample of the sources used in our late effects of pelvic radiotherapy information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
National Institute for Health and Care Excellence (NICE). Clinical Knowledge Summary Faecal incontinence in adults: Faecal incontinence. Last revised in September 2022. Available from https://cks.nice.org.uk/topics/faecal-incontinence-in-adults/management/faecal-incontinence/[accessed March 2026]
S Haas, A Højer Mikkelsen, C Jensenius Skovhus Kronborg et al. Management of treatment-related sequelae following colorectal cancer. PubMed Colorectal Disease Journal.15 August 2022. Available at https://pubmed.ncbi.nlm.nih.gov/35969031/ [accessed March 2026]
V Sun, C Wendal, W Demark-Wahnefried et al. Diet and Behaviour Modifications by Long-Term Rectal Cancer Survivors to Manage Bowel Dysfunction-Associated Symptoms. PubMed. Nutrition and Cancer. 2020 January/ Available at www.ncbi.nlm.nih.gov/pmc/articles/PMC6456395/ [accessed March 2026]
R Dalsania, K Shah, E Stotsky-Himelfarb, S Hoffe et al. Management of Long-Term Toxicity from Pelvic Radiation Therapy. Gastrointestinal cancer- Colorectal and anal. Ascopubs April 2021. Available at https://ascopubs.org/doi/pdf/10.1200/EDBK_323525 [accessed March 2026]
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