Soft-tissue sarcoma (paediatric)

A soft-tissue sarcoma is a tumour that develops from muscle or soft tissue. These are sometimes called malignant mesenchymal tumours.

In this section

Rhabdomyosarcoma is the most common type of soft-tissue sarcoma in childhood. This is a cancer of primitive muscle cells and can develop anywhere in the body. The most common sites are around the head and neck, bladder, or testes in boys.

Who gets soft-tissue sarcoma?

About 60 children develop a soft-tissue sarcoma in the UK each year. It is slightly more common in boys than girls. About two-thirds of rhabdomyosarcomas occur in children under six years of age.

The cause of soft-tissue sarcomas is unknown. There may be genetic factors in some children, for example, those with Li Fraumeni syndrome, have an increased risk of developing rhabdomyosarcoma.

Signs and symptoms

The signs and symptoms will depend on where the tumour develops. The most usual sign is a swelling or lump. Other symptoms may include:

  • Blocked nose or discharge
  • Swollen or protruding eye
  • Tummy (abdomen) swelling, discomfort or difficulty going to the toilet (constipation)
  • Blood in the urine or difficulty passing urine

Tests / investigations

We will need to carry out some tests to find out as much as possible about the type position and size of the tumour. These tests include:

  • Chest X-ray – to see whether the tumour has spread to the lungs.
  • Ultrasound scan – this will tell us the position and size of the tumour.
  • CT scan or MRI scan – a scan of the affected tissue and chest will be carried out. This will give us more information about the tumour and whether it has spread.
  • Biopsy – this is a small operation, usually under general anaesthetic, to remove some tissue.
  • Bone marrow aspirate and trephine – these tests will tell us whether the tumour has spread to the bone marrow.
  • PET/CT scan – this will tell us whether there is spread to other parts of the body


Staging refers to the size of the tumour and whether it has spread. Knowing the stage of the cancer helps the doctors decide on the most appropriate treatment for your child. We use TNM (tumour, node, metastases) staging for soft-tissue tumours with a simplified version as follows:

  • Stage I: Tumour confined to the organ or tissue of origin with no evidence of lymph node involvement or distant spread (metastases).
  • Stage II: Tumour involving one or more adjacent organs or tissues, a collection of fluid (malignant effusion) or multiple tumours in the same organ, with no evidence of lymph node involvement or distant metastases.
  • Stage III: Any of the above with lymph node involvement.
  • Stage IV: Evidence of distant metastases.

Treatment of soft-tissue sarcoma

The treatment for soft-tissue sarcoma involves chemotherapy, surgery and radiotherapy. This depends on the site, stage, appearance down the microscope (histology) and response to treatment.


A combination of anti-cancer drugs is used to destroy the cancer cells. The treatment is normally given every one to three weeks. The exact combination and number of courses depends on the response of the tumour and the risk group. The risk group takes into account the stage, type of tumour, where it is and the age of your child. Some children will need high-dose chemotherapy with a stem cell transplant.

If your child takes part in a clinical trial, the treatment is explained in more detail in the specific trial information sheet. An outline of the treatment will be provided in the form of a ‘road map’.


An operation may be needed to remove residual tumour following chemotherapy, if the tumour can be removed easily without damaging other tissues.


Radiotherapy may be needed if surgery is not possible, where there is tumour left behind after surgery, in some limb tumours and those which show certain histological features. See the Children’s Unit booklet Radiotherapy treatment for more details on this type of treatment.

Clinical trials

Clinical trials are medical research trials involving patients that are carried out to try and find new and better treatments. In cancer, clinical trials are most commonly used to try and improve different forms of treatment such as surgery, radiotherapy or chemotherapy.

The treatment being tested may be aimed at:

  • improving the number of people cured (for example, trying new types of surgery or chemotherapy)
  • improving survival
  • relieving symptoms of the cancer
  • relieving the side effects of treatment
  • improving the quality of life or sense of well-being for people with cancer.

Clinical trials may also involve research aimed at understanding more about the tumour’s biology. You may be asked to allow us to do research on the tumour sample removed at surgery, or on blood samples.

Well-run clinical trials have led to a significant improvement in the treatment of children with cancer. If you are asked to consider entering your child into a clinical trial you will be given specific information about the trial before deciding whether to take part.

Effects of treatment

About two thirds of children with soft-tissue sarcomas are cured, however for the individual child this depends on the risk group and whether the tumour has spread.

General side effects of chemotherapy

Bone marrow suppression (myelosuppression)

Chemotherapy drugs decrease the production of blood cells by the bone marrow for a variable period of time. This results in low red blood cells (anaemia), low white blood cells (neutropenia) and platelets (thrombocytopenia). Your child may need blood or platelet transfusions and will be at increased risk of infections. The doctors and nurses caring for your child will tell you more about these side effects.

Nausea and vomiting

Some of the chemotherapy drugs used may make your child feel sick or vomit. We will give anti-sickness drugs at the same time to stop nausea and vomiting. These are usually very effective.

Hair loss

Temporary hair loss is common.

Specific drugs

For details of the side effects of individual drugs please see Macmillan specific drug information leaflets.

What are the possible long-term effects of treatment?

A small number of children develop side effects many years later because of the treatment they have received. These include growth problems, impaired heart and kidney function, impaired fertility and a small risk of developing a second cancer later in life. Teenage boys have the option to store sperm for use in later years.

About five years after treatment finishes we will transfer your child’s care to our long-term follow-up clinic. Your child will be seen at regular intervals in this clinic, indefinitely, so that we can help with any long-term effects of the treatment.