Biological therapy for soft tissue sarcoma

Biological therapies are treatments that use natural substances from the body, or that change the way cells signal to each other. They can stimulate the body to attack or control the growth of cancer cells. There are many different types of biological therapy and some work well for particular types of soft tissue sarcoma.

Imatinib (Glivec) is a type of biological therapy called a tyrosine kinase inhibitor. This means it blocks a receptor on the cell which stops a chemical (an enzyme) that a cancer needs in order to grow. Glivec is used to treat a very particular type of soft tissue sarcoma called a gastro-intestinal stromal tumour (GIST). About 6 out of 10 cases of GIST are found in the stomach. The rest are found in other parts of the digestive system, including the small and large bowel.

Glivec may also be given to treat a rare, superficial, low grade type of sarcoma known as dermatofibrosarcoma protruberans (DFSP).

The National Institute for Health and Clinical Excellence (NICE) recommend Glivec as the first choice of treatment for people with GIST that can't be completely removed with surgery. They say that the GIST cells should be tested to see if they have a protein on the cell surface called CD117. Nearly all GIST tumours are CD117 positive. Doctors also call this 'c-kit positive' because it is a fault in the c-kit gene that causes the cells to make too much of the CD117 protein.

You usually have this test on tumour tissue removed during surgery. Glivec works best on sarcoma that is CD117 positive. Even if your GIST tests negative for CD117, your specialist may still recommend Glivec. GISTs that test negative for CD117 can still respond to this type of treatment.

Researchers have been looking at whether Glivec can reduce the risk of GIST coming back after surgery. People in one trial took Glivec for one year after surgery. This is called an adjuvant treatment. The trial found that people who had taken Glivec were at less risk of the GIST coming back during the first year but after 6 months of stopping treatment their risk was the same as those people who hadn't taken it. There is further research going on looking at taking Glivec for 2 and 3 years after surgery. The results won't be available until between 2011 and 2015. In England, The National Institute for Health and Clinical Excellence (NICE) decided not to recommend it as an adjuvant treatment for use within the NHS but say they will re-look at it once the results of a European trial are available in late 2011.In August 2010, the Scottish Medicines Consortium (SMC) recommended Glivec should be available within the NHS in Scotland as an adjuvant treatment for people who have CD117 positive GIST. It is only for people who have a high risk of their tumour coming back after surgery.  

Glivec is a tablet. So you can have treatment at home. The most common side effects are tiredness (fatigue) and sickness. Some people also have water retention, causing swelling of the hands and feet and around the eyes. About half the people treated are sick or have diarrhoea. You may also have a rash or headaches. There is detailed information about glivec in our section about cancer drugs.

Sunitinib (also called Sutent) is another type of tyrosine kinase inhibitor. It blocks receptors on the surface of the cancer cells. This stops particular chemical processes that tell the cell to grow and divide. Sunitinib works on several different receptors on the cell at the same time and so is called a multi kinase inhibitor. It starves the tumour of nutrients by

• Blocking the receptors
• Stopping the tyrosine kinase from telling the cell to grow
• Stopping the tumour developing blood vessels

Sunitinib has been approved by the National Institute for Health and Clinical Excellence (NICE) in England and Wales and by the Scottish Medicines Consortium (SMC) in Scotland as a possible treatment for people with GIST who have had imatinib (Glivec) treatment that has not worked or has caused bad side effects. Side effects reported with sunitinib include tiredness, diarrhoea, skin discolouration, a sore mouth, taste changes, sore hands and feet, raised blood pressure and loss of appetite. There is information about coping with the side effects of sunitinib in the cancer drugs section of CancerHelp UK.