Radiotherapy for soft tissue sarcoma

Radiotherapy is a common treatment for soft tissue sarcoma. It uses high energy x-rays to destroy cancer cells. You usually have external radiotherapy. This means using radiation from a machine to destroy the cancer. 

In some situations, you might have external radiotherapy as proton beam therapy. 

Why you might have it

Your doctor might recommend you have radiotherapy for one of the following reasons:

• to shrink the cancer before surgery - often used for large or deep or high grade sarcomas
• before surgery to reduce the risk of the cancer coming back in the future
• to try to stop sarcoma coming back after surgery
• to shrink secondary cancers
• to slow the growth of advanced sarcoma, and to relieve symptoms

In the UK, radiotherapy is part of standard treatment for:

• high grade sarcoma 
• sarcoma larger than 5cm 
• sarcoma that can't be completely removed with surgery 

Usually you have radiotherapy before or after surgery, or with chemotherapy. Rarely you have radiotherapy as your only treatment for soft tissue sarcoma. 

Radiotherapy before surgery

Your doctor may suggest you have radiotherapy before surgery. It is called neoadjuvant radiotherapy.

Radiotherapy can shrink the sarcoma and make it easier to remove. You may then be able to have a smaller operation.

Radiotherapy before surgery may also reduce the risk of the cancer coming back in the future. It does this by killing off any cells close to important structures such as:

• nerves
• blood vessels
• bone

Wide clear margins are often difficult to get with limb sparing surgery alone.

Radiotherapy is also used to kill off any cells in the area around the tumour. These cells may have broken away from the main tumour.

Some research into radiotherapy before surgery has shown that it can increase the risk of wound complications after your operation. This is particularly the case for sarcomas in the leg. But it may be the best choice of treatment for sarcomas in some parts of the body. 

The dose of radiotherapy you have before surgery is smaller than when you have it after surgery.

Radiotherapy after surgery

You might have radiotherapy after surgery to kill off any sarcoma cells that may have been left behind. This is called adjuvant radiotherapy.

You usually have between 6 and 7 weeks of treatments each weekday, with a rest at weekends. The treatment begins after your wound has completely healed. This is because it could slow down the healing process.

Radiotherapy for advanced sarcomas

For advanced sarcomas, you might have radiotherapy:

• to control the growth of a sarcoma that has come back
• for sarcoma that has spread and surgery isn't possible

Radiotherapy may not get rid of it completely. But it could help to shrink the tumour, or slow its growth and control symptoms. 

This type of radiotherapy is called palliative treatment. You usually have a few treatments, rather than several weeks of treatment. For example, you might have one treatment a day for a few days. Or you may have several treatments with a few days break between each.

You might have chemotherapy at the same time.

Radiotherapy for sarcoma that has spread to the lung (metastasis)

Some people might have a type of radiotherapy called stereotactic radiotherapy (SRT). It gives radiotherapy from many different angles around the body. The beams meet at the tumour. This means the tumour receives a high dose of radiation and the tissues around it receive a much lower dose. This lowers the risk of side effects.