

Abdominal or pelvic radiotherapy side effects: pain

Nurse and patients talking about cancer

This page tells you about pain in the lower abdomen (pelvic area) after radiotherapy to the pelvis and what can treat the pain. There is information about


Why pain happens

After radiotherapy to the lower part of the abdomen (pelvis), you might get pain some time afterwards. Pain can occur for various reasons. It is important to see your doctor quickly if you have pain. The type of pain that happens with each cause, along with other symptoms, is described below. There is information about coping with pain in the cancer and pain control section.



Bladder infections can cause pain and are more common after pelvic radiotherapy. The pain is usually worse when the bladder is full. It may be at its worst when you are passing urine or just afterwards. Your urine may be cloudy or smelly or have small amounts of blood. You may also feel ill, have a high temperature or feel sick (nauseated). Your urine will need to be tested to find out which type of infection you have. Your doctor can then prescribe the correct antibiotic.


Bowel changes

Cramps (spasm) of the muscles lining the bowel can cause pain. This type of pain is made worse when you have your bowels open. The pain is cramp like and may come in waves. Constipation or a narrowing of the back passage (an anal stricture) can cause pain. Sometimes the pain may be due to a split in the skin of the anus known as a fissure. A fissure causes a very sharp and intense pain when you have your bowels open. 

Your doctor may ask you to have an examination of the bowel to find out whether there are any changes. This examination is done by putting a flexible tube into the bowel (a flexible sigmoidoscopy). A specialist in bowel problems (gastroenterologist) usually does this test.


Pelvic bone changes

Unfortunately radiotherapy treatment for cancer in the pelvic area can sometimes lead to hip and pelvic bone problems later in life. Radiotherapy can damage our bones in different ways. Problems after pelvic radiotherapy may include 

Weaker pelvic bones

Radiotherapy can damage the bone cells themselves, and also the supply of blood to the bones. The blood supply delivers nutrients (food) to the bones. Without these nutrients the bones become weaker. When bones are damaged because of a loss of blood supply, this is called avascular necrosis. Damage to the bones can cause pain and sometimes makes it hard to walk or climb stairs.

Your doctor may monitor you carefully after pelvic radiotherapy, including checking your bone strength with a DEXA scan. They may suggest treatment with painkillers and walking aids to help you get around, such as a stick. You might also take drugs to strengthen the bones called bisphosphonates. These drugs can help to control pain and reduce the risk of fractures.

Tiny cracks in the bones

Sometimes, tiny cracks can appear in the pelvic bones some years after radiotherapy. They are called pelvic insufficiency fractures. This is more likely to happen in people who have general weakening of their bones as they get older (osteoporosis). It is also more likely in people who are taking hormone therapies or steroids

The pain in this case can be quite bad. It usually gets worse if you move around or do exercise and gets better when you sit still or rest. This type of pain normally goes away overnight. It does not stop you from sleeping well. Your doctor may ask you to have X-rays, a CT scan or an MRI scan (or a combination of these) to see if there are any fractures in the pelvic bones.

If there is a high risk of fracture your doctor may recommend a hip replacement or surgery to strengthen the bone. Your doctor will ask you to see an orthopaedic surgeon (a specialist in bone disease and repair). Surgery for a hip replacement means a stay of about a week in hospital, as well as several weeks recovery time afterwards.


If the cancer comes back

Pain can also be caused if the cancer has come back. This is what many people who get pain after radiotherapy worry about most. You can talk to your doctor about the chance of your cancer coming back.

If the pain is caused by cancer, it may be there constantly, but for some people it comes and goes. It tends not to go away when you rest. Or it may get worse when you exercise or move around. The pain may also be there at night and keep you awake. The pain may not be very bad and may go away if you take mild painkillers. However, if you have this type of pain, your doctor should examine you and should arrange for you to have X-rays, a CT scan or an MRI scan or a combination of these to find the cause.


Getting more information

We have detailed information about external radiotherapy and internal radiotherapy in this section. There is also detailed information about the side effects of radiotherapy.

We have pages about the other side effects of abdominal or pelvic radiotherapy, including


Our general organisations page gives details of people who can provide information about radiotherapy. Some organisations can put you in touch with a cancer support group. Our cancer and treatments reading list has information about books, leaflets and other resources about radiotherapy treatment.


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Updated: 14 May 2014