Introduction
Sarcomas are tumours that develop from the supporting tissues in the body which include the bones, muscles, fat, blood vessels, nerves and joints.
Sarcomas are rare. All the various types of sarcoma make up just 1% of all cancers. Because they are rare, sarcomas are often not diagnosed – however, any swelling in the soft tissues greater than 5cm in size could be a sarcoma and should be referred to a specialist centre for investigation. Even when samples of these tumours are taken for examination under a microscope, making the diagnosis can be very difficult.
The cells in sarcomas often look like cells from cartilage, fat or muscle. The treatment for different types of sarcoma varies according to the type of tumour and whether it is a fast or slowly growing type – specialist centres have the expertise to categorise these tumours and so offer the best options for treatment and the best results for patients.
Sarcomas can grow almost anywhere in the body causing a swelling and sometimes pain. Left alone, sarcomas continue to grow in size causing further symptoms by pressing on other organs, as well as spreading to other parts of the body through the lymphatic system or the blood causing secondary (or metastatic) tumours in almost any organ in the body.
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Muscle Cell Sarcomas
Muscle cell sarcomas are very rare. There are two main types of muscles in the body. The first type are the active (striated) muscles which we use to move – sarcomas which resemble cells from these muscles are called rhabdomyosarcomas.
Rhabdomyosarcomas develop most commonly in the head, neck, arms and legs but they can develop anywhere in the body.
Sarcomas which resemble cells from the second type of muscle (smooth muscle) found in the stomach or heart, are called leiomyosarcomas.
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Bone Cell Sarcomas
Most cancers found in bones are not sarcomas but lung, breast and prostate cancers that have broken off and spread to the bones causing secondary cancers. True bone cell sarcomas are of the following types:
Osteosarcoma
The most common bone cell sarcoma is an osteosarcoma. This affects mainly the young and the very old. In children, teenagers and young adults the most likely symptoms are a strange pain or a bony lump. In elderly people sarcomas can develop from Paget's disease and are often noticed following a fall.
Paget's disease of the bone affects people over the age of 40. It is more often found in men than in women and occurs more commonly in the UK than anywhere else in the world. It is not the same as Paget's disease of the breast, which is a type of skin cancer.
Paget’s disease of the bone is a condition that develops gradually over time affecting bone growth. Most commonly it affects the spine, the pelvis, the legs, the skull and the collarbone, causing the bones to become larger and deformed. Affected bones become weaker and may break.
Chondrosarcoma
Chondrosarcoma is a type of sarcoma whose cells resemble cartilage tissue cells. Chondrosarcoma is most commonly found in the femur (thigh bone), arm, pelvis, knee and spine.
Chondrosarcoma is rare and is usually found in men and women between the ages of 50 and 70.
Ewing's sarcoma
Ewing's Sarcoma is the name given to a very rare group of sarcomas that affect teenagers. Ewing's sarcoma usually starts in the bone - most commonly the pelvis, femur (thigh bone) and tibia (shin bone).
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Gastrointestinal Stromal Tumours (GIST)
Gastrointestinal Stromal Tumours (GIST) are rare tumours of the digestive system (1-3% of all gastrointestinal malignancies) and are a form of sarcoma. 70% occur in the stomach, and they can spread to the liver and elsewhere within the abdominal cavity.
Until recently, GISTs were notoriously difficult to treat. However, a new drug imatinib has been found to be effective in treating these sarcomas. Another new drug, sunitinib, has also been shown to be helpful.
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Malignant Fibrous Histiocytoma (MFH)
Malignant Fibrous Histiocytoma (MFH) is an uncommon form of sarcoma which is found in the fibrous tissue in and around the bones.
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Sarcomas arising in Fatty Tissues
Sarcomas made up of cells that resemble fat cells are called liposarcomas. Like other sarcomas they are rare. There are three main types:
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Sarcoma Risk Factors
In most cases there is no clear reason for a sarcoma to have developed, so for most patients there are no risk factors to avoid.
However, osteosarcomas may develop in patients with Paget’s disease of the bone.
People with some rare inherited genetic conditions (such as neurofibromatosis, Gardner syndrome, and retinoblastoma) are also at greater risk. Anyone with a family history of these conditions should seek medical advice and have regular checks to ensure that any tumour that develops is detected early. However, most sarcomas are not inherited.
Sarcomas can occur at any age. In general they are more common in people over 30, but some, for example Ewing’s sarcoma, are more common in the teenage years.
Sarcomas can very rarely occur following radiotherapy for another type of cancer. There is usually a gap of at least 5–10 years before a sarcoma develops and improvements in radiotherapy mean that the risk of developing a sarcoma is getting less.
Some types of chemical (such as vinyl chloride, some types of herbicides and dioxins) are linked to the development of sarcomas and exposure to these chemicals should be avoided by using alternatives or ensuring that all recommended safety procedures are followed.
There is no evidence that injuries cause sarcomas to develop, even though it is often some form of accident which draws attention to a lump which is in fact a sarcoma that has not previously caused any symptoms.
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Preventing Sarcoma and Early Detection
In most cases there is no clear reason for a sarcoma to have developed, so for most patients there are no risk factors to avoid.
As with almost all forms of cancer, the earlier the diagnosis is made the better. Smaller tumours that have not spread to other parts of the body will require simpler treatments involving less hospital care and a higher chance of returning completely to normal.
Awareness is critically important to early diagnosis. Any swelling in the soft tissues greater than 5cm in size could be a sarcoma and should be referred to a specialist centre for investigation. In practice, as many as 10% of all swellings of this size are sarcomas.
People exposed to chemical agents known to be associated with the development of sarcomas should, if possible, switch to less toxic agents. However, if this cannot be done they should ensure that all recommended safety procedures are followed.
Patients with some rare inherited genetic conditions (such as neurofibromatosis, Gardner syndrome and retinoblastoma) are also at greater risk and so should undergo regular check-ups with their doctor.
Patients who have previously been treated with radiotherapy should be aware that a sarcoma in the same site is unlikely but possible and so should seek medical advice as soon as possible if there is a lump or pain that does not quickly disappear.
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Treatment of Sarcomas
Successful treatment of sarcomas requires a specialist team of health professionals, each with their own expertise. The multidisciplinary team will usually include surgeons, pathologists, medical oncologists, radiation oncologists and their support teams.
Together, they will analyse all the information about the exact type of sarcoma, how fast the tumour is growing, and whether there has been any spread to other areas of the body. They will also consider the patient’s general health and their own preferences with regard to treatment. Ultimately, the choice of treatment rests with the patient based on the advice of all the specialists involved.
Surgery, radiotherapy, chemotherapy and, less commonly, the newer targeted therapies (monoclonal antibodies) are all used to treat sarcomas. Usually more than one form of treatment is required. Using the combined knowledge of all the multidisciplinary team members these different treatments can be combined to produce better results than any one treatment given on its own.
The recommended treatment will depend on the type of tumour, where it is, whether it has spread to other areas and the patient’s own preferences once the options for treatment have been explained.
As there are so many different forms of sarcoma that can develop in any part of the body, this section on treatment options can only provide a very broad overview of the treatments available.
Before any treatment can be recommended, a definite diagnosis is required. This usually involves taking a small sample of the tumour through a small needle so that cells from the tumour can be analysed. CT or MRI scans will show the size of the tumour, exactly where it is and whether it is extending in any particular direction.
Surgery
Surgery is an important treatment for many forms of sarcoma, often combined with radiotherapy, chemotherapy and other treatments.
The aim of surgery is to remove the tumour or as much of the tumour as possible. Usually, the cancer is removed with a margin of normal tissue around it so that there is the maximum chance of removing all the malignant cells. This reduces the risk of the sarcoma coming back in the same place.
Using radiotherapy, chemotherapy or both (chemoradiation) before surgery can in some cases reduce the size of the tumour and make surgery easier. Radiotherapy is often used after surgery to destroy cancer cells that may not have been removed from the cancer site and chemotherapy can be used to destroy cancer cells that have spread to more distant areas of the body.
In the past, sarcomas of the arms and legs were treated by amputation. However, it is now usually possible to just remove the cancer and a safe margin of tissue around it, particularly if further chemotherapy or radiotherapy is used.
Radiotherapy
Radiotherapy is used in the treatment of sarcomas both before and after surgery. It is less common to use radiotherapy before surgery, but when it is used at this stage the aim is to shrink the size of the tumour and so make it easier to remove. After surgery, radiotherapy is used to destroy any remaining cells and prevent recurrences. Radiotherapy is also used in combination with chemotherapy and is carefully planned to meet the needs of each individual patient.
Radiation from a range of different sources is delivered in a variety of ways to maximise the killing effect of radiation on cancer cells whilst protecting, as far as possible, normal cells from its effects.
Radiation works by damaging the genetic material in the cell nucleus making it impossible for the cell to grow and divide, thereby shrinking the tumour as a whole.
External radiation sources are like X-ray machines that produce a beam or radiation into the cancer. By directing the beam from different angles, the maximum effect of radiation can be targeted at the cancerous tumour with the surrounding tissues receiving much smaller doses.
Radiotherapy may be used after operations for sarcomas in the chest or abdomen to try to make sure that any remaining cancer cells are destroyed.
Chemotherapy
Chemotherapy – the use of anti-cancer drugs - is used to destroy cancer cells, often in combination with surgery and radiotherapy and is effective in treating many forms of sarcoma. Chemotherapy is often given before surgery to shrink larger tumours. In the treatment of sarcomas of the limbs, and especially with Ewing’s sarcoma, chemotherapy may avoid the need for amputation. Chemotherapy is frequently continued after surgery to destroy any remaining cancer cells and prevent the sarcoma from spreading elsewhere in the body.
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Looking after Yourself
There are many different types of sarcoma, with different forms of treatment, some of which include radiotherapy. When radiotherapy is used, either as the sole treatment or in combination with surgery, it is effective in many cases but can cause a number of side effects. Some patients will not experience any side effects, whilst others may find several troublesome. Fortunately, many of these side effects disappear soon after the treatment ends and the symptoms can usually be treated, so if you do experience any problems it is important to mention them to your doctor or nurse, so they can give you the treatment you need.
Skin irritation can be a problem particularly towards the end of treatment. If this occurs keeping the skin dry, and using a weak hydrocortisone cream if needed will help.
If the bowel is included in the treatment area diarrhoea may be a problem and can be treated with medication if necessary. Many clinicians suggest that a low-residue diet is helpful but not everyone agrees with this approach. Diarrhoea quickly clears up once treatment is finished.
If the joints are in the treatment area they can become stiff, and the muscle around them can develop scar tissue. To prevent this physiotherapy during treatment and for some months afterwards is often recommended.
Whatever the problem, do not assume that nothing can be done about it – ask your doctor or nurse: do not just grin and bear it.
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Questions for your Doctor
Before making up your mind about the best treatment option for you, you will need information about your cancer, the treatments available in your area and what they will involve, what to expect from the treatment, what side effects you might experience and how these may change over time as well as what your doctors believe would be most effective in combating your cancer.
For different patients the answers will be different, so it is important to discuss all these issues with your doctor so that you make the right choice for you.
You will have your own questions but some issues you might want to raise are:
- What does the treatment involve?
- What are the benefits I might get?
- How good are my chances of getting those benefits?
- Could having the treatment make me feel worse? If so, in what way?
- Are there alternative treatments?
- What are the risks of the treatment?
- Are the risks minor or serious? How likely are they to happen?
- What care will I need after treatment?
- What happens if something goes wrong?
- What may happen if I don’t have the treatment?
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Conclusion
There are many different types of sarcoma. They are all rare and require specialist assessment and treatment. A particular problem with all rare tumours is awareness - any swelling in the soft tissues greater than 5cm in size could be a sarcoma and should be referred to a specialist centre for investigation.
Treatments for sarcoma are tailored to the patient’s needs taking into account clinical and personal factors.
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