Rhabdomyosarcoma in children: symptoms, diagnosis and treatment

The Children and Young People's Cancer Association (CCLG) explains that sarcomas are rare tumours that develop in the supporting tissues of the body, such as bone, muscle or cartilage. Soft tissue sarcomas can develop in muscle, fat, blood vessels or any of the other tissues that support, surround and protect the organs. Rhabdomyosarcoma is the most common soft tissue sarcoma in children.

It has muscle-like features and can grow in any part of the body. The CCLG says that in children about 20% of rhabdomyosarcomas have a gene rearrangement involving the PAX and FOXO1 genes (fusion positive), and the remaining tumours do not have the gene fusion (fusion negative). This genetic information helps doctors decide on the best treatment.

The CCLG says the most common sign is a lump or swelling. The NHS says that for soft tissue sarcoma generally the lump is usually solid to the touch, painless and hard to move around under the skin, and that it will continue to grow and may become painful. Other symptoms depend on the part of the body affected.

The NHS says to see a GP if your child has a lump or swelling somewhere on their body. Lumps and swellings are very common and can be caused by many different conditions, so having one does not definitely mean cancer, but it is important to get it checked, because if symptoms are caused by cancer, finding it early may mean it is easier to treat.

The GP will examine the lump and may arrange blood tests and an ultrasound scan. The NHS says they may refer your child for more tests or to a specialist in hospital, which may be an urgent referral if there are certain symptoms. An urgent referral does not definitely mean cancer.

The CCLG says the causes are unknown, but research is going on all the time. Children with certain rare genetic disorders, such as Li-Fraumeni syndrome, have a higher risk of developing rhabdomyosarcoma.

The CCLG says different tests are usually needed. Your child may need a small operation, usually under general anaesthetic, to remove a sample from the tumour (a biopsy) so that it can be examined under a microscope. Tests may also check the exact size of the tumour, whether it is fusion positive or fusion negative, and whether it has spread. These may include a chest X-ray, ultrasound scan, CT, PET/CT or MRI scans, blood and bone marrow tests and molecular gene testing.

Staging describes the size of the cancer and whether it has spread. The CCLG says the staging system for rhabdomyosarcoma is based on where in the body the tumour started and whether it is in only one part of the body (localised) or has spread to another part (metastatic). Knowing the stage helps doctors choose the most effective treatment.

The CCLG says treatment depends on the size of the tumour, the type of rhabdomyosarcoma, its position in the body and whether it has spread. The three main types of treatment are chemotherapy, surgery and radiotherapy, and your child may have a combination.

The CCLG says a small number of children may develop long-term side effects many years after treatment. These may include reduced bone growth, changes in the way the heart, lungs and kidneys work, a risk of infertility, and a small increase in the risk of another cancer later in life. Not all late effects happen to all children. Your child's doctor or nurse will talk to you about possible late effects and watch for them in follow-up clinics.

Once treatment has finished, the doctors will monitor your child closely with regular appointments to check the cancer has not come back and there are no complications. After a while you will not need to visit the clinic so often.

The CCLG information applies to children aged 0 to 14 years, and points to separate information for teenagers and young adults aged 15 to 24. The NHS describes soft tissue sarcoma generally as a rare cancer that starts in soft tissue, such as muscle and fat.

A diagnosis of cancer in a child is overwhelming. Your child's specialist team can explain treatment and side effects, and the CCLG provides information for families. Ask the team about local and national support services, including those for brothers, sisters and parents.

Children with cancer are treated within NHS children's cancer services. The CCLG says that where trials are not available your child's doctors will offer the most appropriate treatment using guidelines agreed by experts across the UK, which the CCLG helps to produce. Your GP or paediatrician is usually the route into this pathway.