Effects of pelvic radiotherapy treatment on hip bones
Pelvic radiotherapy means radiotherapy to the pelvic area (pelvis). The pelvis is the lower cavity of the body within the area between the hip bones. It contains the pelvic organs, including the bladder and lower bowel and the reproductive organs.
Unfortunately treatment for cancer in the pelvic area can sometimes lead to hip and bone problems later in life. Radiotherapy can damage our bones in different ways. It 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. Sometimes, tiny little cracks can appear in the bones some years after radiotherapy. They are called pelvic insufficiency fractures and need to be diagnosed by a combination of X-rays and scans.
But remember that radiotherapy works well at treating cancer and many people are cured because of this treatment. You may have pelvic radiotherapy to treat
Doctors treating people with cancer have researched the effects of radiotherapy on the bones. They know that people treated with radiotherapy to the pelvic area may be more likely to develop a fracture. But because these studies were small, they don’t tell us the exact risk of bone fracture.
Doctors in America reported on a large study that looked at the risk of pelvic fractures after pelvic radiotherapy. The study looked at over 6,000 women who'd had treatment for either anal, rectal or cervical cancer. Their average age was 74. The women who had radiotherapy were found to be at higher risk of pelvic and hip fractures. They were also at higher risk of fractures of the base of the spine (the sacrum). Women treated with radiotherapy for anal cancer seemed to be at particular risk of fracturing their hip.
To understand these figures, we need to compare them to normal risk. In the general population, 17 out of 100 women (17%) will fracture their hip at some point between the age of 65 and the end of their life. The researchers in the American study mentioned above have worked out that this lifetime risk could be as high as 27 people out of every 100 (27%) who’d had pelvic radiotherapy. Because this study only involved older women, we don’t know if younger women would have the same risk of fractures. This study showed that people treated for anal cancer were at the greatest risk. But people with rectal and cervical cancer also had an increased risk of hip fracture.
There is very little information about how other cancer treatments affect the bones. Chemotherapy in younger women can cause an early menopause. This means that the ovaries stop producing oestrogen, which can increase women’s risk of bone thinning and so fracture. For this reason, young women who’ve had intensive cancer treatment may be advised to take hormone replacement therapy (HRT) by their doctors afterwards. Hormone therapies can block or stop oestrogen production and long term, this may also cause problems with bones.
Treatments for men that lower testosterone levels, such as hormone treatment for prostate cancer, also increase the risk of bone thinning.
People who have had a bone marrow transplant or stem cell transplant have high doses of steroids, as well as chemotherapy and often radiotherapy. These treatments may cause problems with bone loss. All these treatments can cause bone problems over time, including the risk of developing avascular necrosis.
Treatment will depend on
- Why your hip is damaged
- Your age
- Whether you are fit enough to have an operation
Your doctor 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.
If surgery is an option, your doctor will ask you to see a doctor who specialises in bone disease and repair (an orthopaedic surgeon). Surgery for a hip replacement means a stay of about a week in hospital, as well as several weeks recovery time afterwards.
The American research into pelvic fractures recommends that doctors should closely monitor women who have had pelvic radiotherapy, including checking their bone density. It also suggests that we need further research to look at ways of reducing fracture risk after cancer treatment.
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