Soft tissue sarcomas are a group of rare cancers affecting the tissues that connect, support and surround other body structures and organs.
Tissues that can be affected by soft tissue sarcomas include fat, muscle, blood vessels, deep skin tissues, tendons and ligaments.
Soft tissue sarcomas can develop in almost any part of the body, including the legs, arms and the trunk (torso).
There are many different types of soft tissue sarcoma, depending on where in the body they are located. For example:
- leiomyosarcomas – which develop in muscle tissue
- liposarcomas – which develop in fat tissue
- angiosarcomas – which develop in the cells of the blood or lymph vessels
- gastrointestinal stromal tumours (GISTs) - which can develop in the connective tissues that support the organs of the digestive system
Soft tissue sarcomas account for around 1 in every 100 cancers diagnosed in the UK.
What causes soft tissue sarcomas?
Cancer develops when cells multiply uncontrollably, forming tumours.
In the vast majority of soft tissue sarcomas it's unclear what causes this to happen but there are a number of factors known to increase the risk, including:
- age – soft tissue sarcomas can occur at any age, including in children, but they are more common in middle-aged or elderly people and your risk increases as you get older
- certain genetic conditions – some genetic conditions, such as neurofibromatosis type 1 and retinoblastoma, are associated with an increased risk of soft tissue sarcomas
- previous radiotherapy – some people who have previously had radiotherapy for another type of cancer develop a soft tissue sarcoma, often many years after their previous treatment
- exposure to certain chemicals – exposure to some chemicals, including vinyl chloride, dioxins and phenoxyacetic herbicides, has been associated with increased rates of soft tissue sarcomas
One particular type of soft tissue sarcoma called Kaposi’s sarcoma – which develops in skin cells – is caused by a virus known as the human herpesvirus type 8 (HHV-8) infecting someone with a weakened immune system (such as people with HIV).
Signs and symptoms
As soft tissue sarcomas can develop in most parts of the body, they can cause a wide range of symptoms.
For example, a tumour near the stomach may cause abdominal (tummy) pain, a feeling of fullness and constipation, whereas a tumour near the lungs may cause a cough or breathlessness.
There are often no obvious symptoms in the early stages of soft tissue sarcomas, although you may notice a soft, painless lump under your skin or deeper, that can't easily be moved around and gets bigger over time.
You should speak to your GP if you have a worrying lump or any other troublesome symptoms. A lump the size of a golf ball or larger should be regarded as suspicious and needs to be investigated urgently.
Although it is much more likely you have a benign (non-cancerous) condition, it is important to get your symptoms checked out.
Diagnosing soft tissue sarcomas
If your GP feels there is a possibility you do have cancer, they will refer you for a number of hospital tests to confirm whether you have a soft tissue sarcoma.
In 2015, the National Institute for Health and Care Excellence (NICE) published guidelines to help GPs recognise the signs and symptoms of soft tissue sarcoma and refer people for the right tests faster. To find out if you should be referred for further tests for suspected soft tissue sarcoma, read the NICE 2015 guidelines on Suspected Cancer: Recognition and Referral.
A diagnosis of a soft tissue sarcoma will usually be made by a hospital specialist and will be based on your symptoms, a physical examination, and the results of:
- a biopsy – where a sample of suspected cancerous tissue is removed using a needle or during an operation so it can be tested and analysed in a laboratory
- imaging tests – a magnetic resonance imaging (MRI) scan is the main type of scan carried out to assess soft tissue sarcomas, although other scans may also be carried out
If a diagnosis of a soft tissue sarcoma is confirmed, these tests will also help determine how far the cancer has spread (known as the 'stage') and how aggressive the cancer is (known as the 'grade').
Treating soft tissue sarcomas
If you're diagnosed with a soft tissue sarcoma your care team of specialist doctors and nurses will help you decide on the most appropriate treatment.
Treatment depends on factors such as the stage and grade of the cancer, the location of any tumours, and your age and general health.
The main treatments used are:
- surgery – to remove any tumours
- radiotherapy – where high-energy radiation is used to kill cancer cells
- chemotherapy – where medication is used to kill cancer cells
Surgery is the main treatment for soft tissue sarcomas that are detected at an early stage.
It involves removing the cancerous tumour along with a section of surrounding healthy tissue. This will help ensure no cancer cells are left behind.
Every effort will be made to reduce the impact of surgery on the appearance and functionality of the affected body part.
But there is a possibility you'll have some difficulty using the part of the body that is operated on after surgery and sometimes reconstructive plastic surgery may be needed to repair significant damage.
In a small number of cases, there may be no option but to amputate the part of the body where the cancer is located, such as part of the leg.
Radiotherapy is often used after surgery to destroy any remaining cancer cells. This is carried out using an external machine that directs beams of radiation at a defined treatment area.
Radiotherapy may also sometimes be used before surgery to make a tumour easier to remove, or as part of your treatment to reduce your symptoms if surgery is not possible.
Common side effects of radiotherapy include sore skin, tiredness and hair loss in the treatment area. These tend to get better within a few days or weeks of treatment finishing.
Read more about the side effects of radiotherapy
Like radiotherapy, chemotherapy is sometimes used before surgery to shrink a tumour and make it easier to remove. This involves being given anti-cancer medication directly into a vein (intravenously).
Chemotherapy may also be used alone or alongside radiotherapy for soft tissue sarcomas that cannot be surgically removed.
Chemotherapy medications have a poisonous effect on the body's cells, and can cause a number of temporary but unpleasant side effects, such as feeling tired and weak all the time, feeling and being sick, and hair loss from several parts of the body.
Read more about the side effects of chemotherapy
As with most types of cancer, the outlook for a soft tissues sarcoma depends largely on how far the cancer has advanced when it is diagnosed.
If the cancer is detected at an early stage and can be removed during surgery, there is a possibility it can be cured.
But you'll need regular check-ups following treatment to check for any signs the cancer has come back. You may also need long-term physiotherapy and occupational therapy to help you manage any physical difficulties resulting from surgery.
A cure is not usually possible if a soft tissue sarcoma is only detected at a late stage when it has already spread to other parts of the body, although treatment can help slow the spread of the cancer and control your symptoms.
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