Risk factors and causes of soft tissue sarcoma

Although the cause of soft tissue sarcoma is unknown, research into this is ongoing. Sarcomas, like other cancers, are not infectious and can’t be passed on to other people.

Age

Sarcomas can occur at any age but are more common in people over 30.

Genetic conditions

Most sarcomas are not caused by an inherited faulty gene that can be passed on to other family members. Members of your family are not likely to have an increased risk of developing a soft tissue sarcoma just because you have.

However, people who have some rare inherited genetic conditions are more at risk of developing a sarcoma. These conditions include neurofibromatosis, Gardner syndrome, Li-Fraumeni syndrome and retinoblastoma. You would normally know if any member of your family had one of these conditions, and their doctor would check them regularly for any sign of a sarcoma.

Previous radiotherapy treatment

Very rarely, soft tissue sarcomas may occur in a part of the body that has previously been treated with radiotherapy for another type of cancer. The sarcoma will not usually develop until at least 5–10 years after the radiotherapy treatment. Improvements in giving radiotherapy treatment mean that the risk of developing a sarcoma is very small.

Exposure to chemicals

The development of some sarcomas may be linked to exposure to some types of chemicals. The chemicals include: vinyl chloride, which is used for making plastics; some types of herbicides (weedkillers); and dioxins, which are a waste product produced during the manufacture of chemicals and fertilisers.

Injury

There is no evidence that an injury can cause a soft tissue sarcoma to develop. It’s possible that an injury may draw attention to a sarcoma that was already there and not causing any symptoms, but the sarcoma will have taken many years to develop.

How common is the Soft tissue sarcoma in India?

Connective tissue and soft tissue sarcoma is one of the rare cancers diagnosed in India. It ranks lower than number 15 among all other cancers for people from the Indian subcontinent1.

In India, between the years 2001-2003, across five urban centers - Mumbai, Delhi, Chennai, Bhopal and Bangalore, – and one rural center - Barshi, a total of 678 cases of connective tissue and soft tissue sarcoma were registered (1.54% of all cancers) for males across all age groups; while 501 cases of connective tissue and soft tissue sarcoma were registered (1.12% of all cancers) for females across all age groups. Considering all men, women and children with all types of cancers together, a grand total of 1,179 cases of connective tissue and soft tissue sarcoma (1.33% of all cancers) were registered at the six centers mentioned above, between the year 2001-20032.

The TATA Memorial Hospital (T.M.H.) in Mumbai, India registered a grand-total of 19,127 cases of all types of cancer patients in the year 2006 for men, women and children combined, out of which 372 (1.94% of the total cases) were diagnosed with the soft tissue sarcoma. Out of the total 372 patients diagnosed with soft tissue sarcoma, mentioned above at the T.M.H., 251 (68%) were males and 121 (32%) were females3.

Symptoms of soft tissue sarcomas

Sarcomas often don’t cause any symptoms for a long time. They can start in any part of the body and the symptoms will depend on the part of the body that is affected.

If the sarcoma is in an arm or a leg, the most common symptom is an uncomfortable swelling in the affected limb. Occasionally, this swelling may be painful or tender, but it may also be painless.

If the sarcoma is in the central part of the body (the trunk), the symptoms will depend on which organ in the body is affected. For example:

a sarcoma in a lung may cause a cough and breathlessness
a sarcoma in the abdomen could cause abdominal pain, vomiting and constipation
a sarcoma affecting the womb may cause bleeding from the vagina and pain in the lower part of the abdomen.

Generally, soft tissue sarcomas do not cause any symptoms until they are quite large and are pressing on an organ in the body or on a nerve or muscle. Things to look out for include:

any lump, especially if it is increasing in size and is bigger than 5cm (2in)
any lump that is painful or tender
any lump that is deep in the body (ie not just under the skin)
any lump that has come back after being surgically removed.

If you notice any of the above, contact your GP; but remember that these symptoms can also be caused by other conditions.

How soft tissue sarcomas are diagnosed

Usually you begin by seeing your GP, who will ask you about your symptoms and examine you. They may arrange for you to have any tests or x-rays that are necessary. You may need to be referred to hospital for these tests and for specialist advice and treatment. If your GP suspects that you might have a sarcoma you will usually be seen at the hospital within two weeks.

At the hospital, the specialist will ask about your general health and any previous medical problems. They will also examine you, which will include feeling the area where there is pain or swelling. You may be asked to have blood tests and a chest x- ray to check your general health.

You are also likely to be asked for your permission to take a sample of the lump to examine under the microscope. This is known as a biopsy and is the only way to tell whether the lump is a cancer or a non-cancerous (benign) tumour. You may have other tests and scans to assess the lump, before a biopsy.

A biopsy can be done in either of the following ways:

Core needle biopsy
Surgical biopsy

Core needle biopsy

A needle is put into the lump to take a sample of cells. Several samples may be taken. A local anaesthetic is injected first to numb the area. If the lump is near the surface of your body and can easily be felt, the doctor will probably just feel it to guide the needle in. If the lump is deep within the body (such as in the abdomen) or is harder to feel, the doctor will use an ultrasound scan or sometimes a CT scan to see where the needle is going and guide it into the right place.

When the cells are looked at under a microscope, the pathologist will be able to tell whether they are benign (not cancerous) or cancerous cells. If the lump is a sarcoma, further tests may be done on the sample to try to find out exactly what type of sarcoma it is.

Sometimes, particularly with children, the biopsy is done under a general anaesthetic.

For most people a needle biopsy will show whether the lump is a sarcoma. Sometimes, not enough cells are collected to give a clear answer, and then a surgical biopsy is needed.

Surgical biopsy

This will only be done if a needle biopsy can’t be used, or doesn’t give a definite result. Surgical biopsy means using a surgical knife (scalpel) to open the area and remove a tissue sample from the lump. If the lump is small enough, the whole of it may be removed.

A surgical biopsy may be done under a local or general anaesthetic, depending on the position of the lump and how deep it is within the body. If the lump turns out to be benign, you may not need to have any more treatment. If it is cancer, your doctor will discuss the treatment options with you.

In the same way as with a needle biopsy, the sample will be sent to the laboratory so that it can be tested. Often a large number of studies will be done even on a very small sample. It can take from a few days to 10 days to get all the results. This can be a worrying time for you, but it is very important that an accurate diagnosis is made so that the most appropriate treatment can be given.

It may help you to talk about your worries with a partner, close friend, relative or counsellor (see the list of useful organisations).

Further tests for soft tissue sarcomas

Your doctor may arrange for you to have one or more of the following tests to find out the size of the sarcoma, exactly where it is and whether or not it has spread to other parts of the body.

Chest x-ray
CT scan
MRI scan
Ultrasound scan of the abdomen
PET scan
Waiting for your test results

Chest x-ray

This will be done to check your general health and to look for any sign that the cancer has spread to your lungs, as this is one of the commonest places for soft tissue sarcomas to spread to.

CT scan

A CT (computerised tomography) scan takes a series of x-rays which builds up a three-dimensional picture of the inside of the body. The scan is painless but takes from 10 to 30 minutes. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.

Having a CT scan

You may be given a drink or injection of a dye which allows particular areas to be seen more clearly. For a few minutes, this may make you feel hot all over. If you are allergic to iodine or have asthma you could have a more serious reaction to the injection, so it is important to let your doctor know beforehand. You will probably be able to go home shortly after the scan is over.

MRI scan

An MRI (magnetic resonance imaging) scan is similar to a CT scan, but uses magnetism instead of X-rays to build up cross-sectional pictures of your body.

During the test you will be asked to lie very still on a couch inside a long tube for about 30 minutes. This is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It is also noisy, but you will be given earplugs or headphones. You can usually take someone with you into the room to keep you company. It is not possible for you to have an MRI scan if you have any metal in your body such as a pacemaker, or surgical clips.

Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort. You will probably be able to go home when the scan is over.

Ultrasound scan of the abdomen

This may be used if you have an abdominal lump. An ultrasound scan uses sound waves to look at internal organs such as the liver and the inside of the abdomen. You will usually be asked not to eat or to drink for a few hours before the test.

Once you are lying comfortably on your back, a gel is spread onto your abdomen. A small device like a microphone, which produces sound waves, is passed over the area. The sound waves are then converted into a picture by a computer. The test only takes a few minutes.

If the lump is in your womb, the ultrasound scan may be done by inserting an ultrasound device into your vagina. This is known as a transvaginal ultrasound scan and gives a very clear picture of the womb.

Having an ultrasound scan

PET scan

PET (positron emission tomography) scans are a newer type of scan and you may have to travel to a specialist centre to have one. They are not always necessary but you can discuss with your doctor whether one would be useful in your case. PET scans can be used to find if a sarcoma has spread to other parts of the body, or to examine any lumps that remain after treatment, to see if these are scar tissue or if cancer cells are still present.

A PET scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. A scan is then taken a couple of hours later. Areas of cancer are usually more active than surrounding tissue and show up on the scan.

Waiting for your test results

It will probably take several days for the results of your tests to be ready and this waiting period will obviously be an anxious time for you. It may help if you can talk things over with a relative or close friend. You may wish to ring Cancerbackup or another support organisation for emotional support.

Staging and grading soft tissue sarcomas

The further tests already described help to find the stage and the grade of the cancer. These help the doctors to decide on the most appropriate treatment.

Grading
Staging

Grading

Grading refers to the appearance of the cancer cells under the microscope. The grade gives an idea of how quickly the cancer may develop. Grading of soft tissue sarcomas can sometimes be difficult, especially for the less common types. There are four grades, from 1 to 4.

Grade 1 means that the cancer cells look very like the normal cells of the soft tissues (called well-differentiated). They are usually slow-growing and are less likely to spread.
Grade 2 means the cancer cells have begun to look more abnormal. They are described as being moderately differentiated.
Grade 3 soft tissue sarcomas are described as being poorly differentiated – the cancer cells look very abnormal, are likely to grow quickly, and are more likely to spread.
Grade 4 soft tissue sarcomas are either poorly differentiated or undifferentiated. Undifferentiated cancer cells are primitive and immature.

They don’t function properly and have no specific appearance. Grade 4 soft tissue sarcomas are likely to grow more quickly and are more likely to spread.

Staging

The stage of a cancer describes its size and whether it has spread beyond its original area of the body.

Several different staging systems may be used for soft tissue sarcomas. A commonly used staging system, produced by the American Joint Committee on Cancer (AJCC), is described below and includes information about the grade of the cancer as well as the stage:

There are four major stages (from 1 to 4).

Stage 1 The cancer is low-grade (grades 1 or 2) and can either be close to the surface of the body (superficial) or deep within the body. There is no sign of any spread.
Stage 2 The cancer is high grade (grades 3 or 4). It is either superficial or deep within the body, but has not spread to lymph nodes or other parts of the body.
Stage 3 The cancer is described as high-grade, large (5cm or bigger) and deep. It has not begun to spread.
Stage 4 The cancer can be any grade, but it has spread to lymph nodes in the area or to any other part of the body, such as the lungs, head or neck. This is known as secondary cancer (or metastatic cancer).

Recurrence means that a soft tissue sarcoma has come back after it was first treated. It may come back in the area where it first started, or it may come back in another part of the body.

TNM staging system

Another staging system known as the TNM system is also commonly used. This can give your doctors more precise information about the extent of the cancer.

T describes the size of the tumour.
N describes whether the cancer has spread to the lymph nodes.
M describes whether the cancer has spread to another part of the body (secondary or metastatic cancer).