Risks and causes of soft tissue sarcomas
This page tells you about the possible risk factors for soft tissue sarcoma. You can find information about
Risks and causes of soft tissue sarcomas
Soft tissue sarcomas are rare cancers. We don’t know exactly what causes them, but there are a number of risk factors that we do know about. As people get older they are more likely to develop sarcoma. Around 40 in 100 soft tissue sarcomas (40%) are diagnosed in people aged 65 or older. But sarcoma can occur in children and young people and almost 1 in 10 (9%) are diagnosed in people younger than 30.
Factors that can increase the risk of sarcoma include
- Radiotherapy treatment for other cancers
- Radiation in the environment (such as after nuclear accidents)
- Having had another type of cancer
- Swelling of a limb due to poor lymphatic drainage (lymphoedema)
- Some rare genetic conditions, including neurofibromatosis, Li Fraumeni syndrome and retinoblastoma
- Some chemicals such as vinyl chloride, dioxins and chlorophenols
- Human Herpes Virus-8 infection (HHV-8) in people with lowered immunity (increases Kaposi's sarcoma risk)
- HIV and AIDS
- Medicines to lower immunity after an organ transplant (can increase Kaposi's sarcoma risk)
- Epstein Barr virus (EBV) infection in children and young people with HIV or AIDS (can increase leiomyosarcoma risk)
- Being born with an umbilical or inguinal hernia
- Being very overweight as a woman (increases the risk of sarcoma of the womb)
Injury and sarcoma risk
Sometimes people think that an injury has caused a cancer. But there is no evidence that an injury of any kind can cause a sarcoma.
You can view and print the quick guides for all the pages in the about soft tissue sarcoma cancer section.
Soft tissue sarcomas are rare cancers. Around 3,300 people are diagnosed with soft tissue sarcoma each year in the UK.
We don’t know exactly what causes soft tissue sarcoma. But there are a number of risk factors associated with this condition. A risk factor is anything that may increase your risk of developing a particular type of cancer. If you have a risk factor it does not mean that you will definitely develop cancer. You can develop a cancer even if you have no known risk factors.
It is difficult to gather reliable information about what causes soft tissue sarcomas because they are a rare type of cancer. There are also many different sub types and each may have different risk factors and causes.
Soft tissue sarcoma can be diagnosed at any age, but as people get older they are more likely to develop it. Around 40 in 100 soft tissue sarcomas (40%) are diagnosed in people aged 65 or older.
Sarcoma can occur in children and young people though and almost 10 in 100 (10%) are diagnosed in people younger than 30. Just over half of these are a specific type called rhabdomyosarcoma, which occurs most often in children aged 4 or younger.
Radiation can increase the risk of sarcoma. Radiation comes from sources such as
Radiotherapy treatment for other cancers can sometimes cause a sarcoma in the treatment area years later. This is because the radiation can affect healthy tissue in the treated area. The amount of increase in risk depends on the age of the person and the dose of the radiotherapy. People treated as children with high doses of radiotherapy have the biggest increase in risk although different studies give different levels. Combining chemotherapy with radiotherapy may increase the risk further.
Radioactive iodine treatment is a type of internal radiotherapy. It uses a radioactive form of iodine called iodine 131 (I-131) to treat hyperthyroidism and thyroid cancer. The radioactive iodine circulates throughout the body in the bloodstream and thyroid cells pick up the iodine. There is limited evidence that radioactive iodine can increase the risk of soft tissue sarcoma.
Only 3 out of every 100 soft tissue sarcomas (3%) are due to previous radiotherapy. They most commonly develop around 10 years after the original treatment. In some people it may be more than 15 years later. If you are having radiotherapy for cancer, it is important to keep in mind how much good the treatment is doing you. Treating the cancer is essential and doctors balance this against the small risk of getting a sarcoma in the future. Radiotherapy treatment is planned very precisely and very little healthy tissue is included in the radiation field. Recent improvements in radiotherapy planning may reduce the number of sarcomas that radiotherapy causes.
Radiation in the environment can also slightly increase the risk of sarcoma. People exposed to the atomic bomb explosions in Japan at the end of World War 2 had higher rates of developing these cancers.
People who have had a previous cancer have a small increase in their risk of developing a soft tissue sarcoma. Some of this can be explained by treatments such as radiotherapy or by swelling (lymphoedema) after breast cancer treatment. But some of these tumours may be caused by other factors such as gene changes linked to sarcoma as well as other cancers. People with breast cancer, kidney cancer, bladder cancer, skin cancer, womb cancer or ovarian cancer are most likely to go on to develop soft tissue sarcoma.
People who had cancer as a child have a higher risk of developing soft tissue sarcoma than the general population. The risk is highest in people who had brain tumours, spinal cord tumours, Hodgkin lymphoma, Wilm's tumour, soft tissue sarcoma or bone sarcoma.
Some types of rare genetic conditions can increase your risk of getting a sarcoma. These are
If any of these conditions run in your family you are likely to know. A genetic condition can crop up in a family that has not had it before but this is very rare.
Neurofibromatosis is a genetic disease in which non cancerous (benign) tumours form in the nerves under the skin and in other parts of the body. This increases the risk of getting a very rare type of sarcoma called a malignant peripheral nerve sheath tumour (MPNST). Less than 5 in 100 people with neurofibromatosis (5%) will have a MPNST at some point in their life. Neurofibromatosis is also called von Recklinghausen disease.
Li Fraumeni syndrome is a genetic syndrome that causes several different types of cancer to occur in affected families. It is sometimes called family cancer syndrome. Families with Li Fraumeni syndrome have a higher risk of breast cancer, brain tumours, leukaemias and other cancers. They also have a higher risk of developing soft tissue sarcoma. Around 18 out of 100 tumours (18%) in people with Li Fraumeni syndrome are soft tissue sarcomas, most commonly rhabdomyosarcoma, leiomyosarcoma, liposarcoma and histiosarcoma.
Retinoblastoma is a type of inherited eye cancer. It is nearly always diagnosed in childhood. Children who have had retinoblastoma have an increased risk of developing a soft tissue sarcoma in the future. Around 13 out of 100 children who have retinoblastoma (13%) develop a soft tissue sarcoma within 50 years. The most common types are leiomyosarcoma, fibrosarcoma and rhabdomyosarcoma. The radiotherapy given as treatment for retinoblastoma may partly account for the increased risk. These children also have an increased risk of getting a type of bone cancer called osteosarcoma.
We don't have clear evidence for whether exposure to certain chemicals can cause soft tissue sarcoma. It is often hard to tell how much people have been exposed to particular chemicals. The number of cases of sarcoma in the studies is also usually very small. Several chemicals are thought to increase the risk of some types of sarcoma and these include
There is no evidence that weed killers (herbicides) or insect killers (insecticides) cause sarcomas at levels that the general public come into contact with.
Vinyl chloride is a chemical used in making some plastics. It is thought that exposure to vinyl chloride at work may increase the risk of sarcoma of the liver. But a large study which looked at cancer risk of people exposed to vinyl chloride at work, did not find an increase in risk of cancer at other sites. So it is not clear whether this chemical can cause sarcomas elsewhere in the body.
Dioxins, including tetra chloro dibenzo dioxin (TCDD) are produced in industries related to paper bleaching and pesticide making. People who work in these industries may be at a slightly increased risk.
Chlorophenols are found in pesticides and antiseptics. Several recent studies found no increased risk through exposure to these chemicals at work or in the general environment. But these chemicals were linked to an increased risk of sarcoma in Swedish studies in the 1990s.
In the UK, Kaposi’s sarcoma is a very rare type of soft tissue sarcoma that develops from cells in the blood vessels. Kaposi's sarcoma is caused by Human Herpes Virus-8 infection (HHV-8), which is also known as Kaposi's sarcoma associated herpes virus (KSHV). Many people have HHV-8 and most do not develop Kaposis sarcoma. But this virus is sometimes able to cause Kaposi's sarcoma in people with lowered immunity.
HIV and AIDS cause lowered immunity and around 80 out of 100 people who get Kaposi's sarcoma (80%) have HIV or AIDS. People taking medicines to suppress their immunity (usually after an organ transplant) also have an increased risk of developing Kaposi’s sarcoma.
An infection called Epstein Barr virus (EBV) has been linked with leiomyosarcomas in children and young people with HIV or AIDS. It has also been linked to leiomyosarcoma in adults taking medicines to lower immunity after a transplant. But only a small number of cases have been recorded in medical journals. There are also a small number of reports of people developing angiosarcoma after kidney transplant.
Radiotherapy and surgery for breast cancer can cause long term swelling (lymphoedema) of the arm. Radiotherapy or surgery to the pelvic area or genital area can cause swelling of the leg. Less than 1 in every 3,000 women who have breast removal (mastectomy) and get chronic lymphoedema develop a type of sarcoma in the arm called angiosarcoma. This is also known as Stewart-Treves syndrome. It takes many years to develop.
More rarely, angiosarcoma may occur in the leg in people who have chronic lymphoedema of the leg.
Children born with a hernia of the tummy button (a congenital umbilical hernia) or a hernia at the top of the leg (an inguinal hernia) are around 3 times more likely to have a Ewing’s sarcoma. An umbilical hernia is caused by a weakness of the muscle around the belly button. An inguinal hernia is a weakness of the muscle in the groin area. It is not clear why hernias increase the risk of sarcoma.
One study found that women who are very overweight (obese) have a higher risk of sarcomas of the womb compared with women who are not overweight.
Some factors have been looked at to see if they can increase the risk of developing sarcoma but the situation is unclear at the moment. These factors include
Sometimes people think that an injury has caused a cancer. There is no evidence that an injury of any kind can cause a sarcoma. But an injury may draw attention to a sarcoma that was already there if the person has X-rays or scans. Cancers take many years to develop. In most cases where people think an injury is responsible, the injury has only happened recently and so is unlikely to be linked to the cancer.
It is not clear whether smoking affects the risk of developing soft tissue sarcoma. One large American study showed that smokers have a higher risk of dying from soft tissue sarcoma than non smokers. But an Italian study showed no increase in risk.
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