Ewing's Sarcoma

Ewing sarcoma is rare, affecting in the region of 30 children per year in the UK. It occurs most frequently between the ages of 5 and 20 being most common in the adolescent years.¹ It is slightly more frequent in males than females.²

The term Ewing sarcoma was first used in 1921³ and describes a cancer which mainly occurs in the bones of the extremities and the surrounding soft tissue.² It accounts for approximately 2% of all childhood cancers and is classified as a primitive neuroectodermal tumour (PNET).¹ Although not hereditary, it is associated with reciprocal translocations at chromosomes 11 and 22.⁴ 90% of affected children will demonstrate an abnormality at two particular gene sites, a finding which helps to establish the diagnosis.

The symptoms and signs of Ewing sarcoma are not in themselves diagnostic but may include:

• Mass or swelling - most commonly in the long bones of the arms and legs, pelvis or chest, but also in the skull and flat bones of the trunk
• Pain in the area of the tumour
• Redness in the area surrounding the tumour
• Malaise
• Anorexia
• Weight loss
• Fever (poor prognostic sign)
• Paralysis and/or incontinence if affecting the spine
• Numbness or tingling as a result of nerve compression by the tumour.

• Trauma
• Benign tumours e.g. neurofibroma
• Other malignancies e.g. lymphoma.

• X-ray of the affected bone - shows bone destruction with overlying onion-skin layers of periosteal bone formation¹
• FBC and lactic dehydrogenase measurement (LDH) - anaemia and raised LDH levels at diagnosis suggest the presence of metastases and are an indication of poor prognostic outcome⁷
• CT/MRI scan to assess extent of disease and local structures involved
• Bone scintigraphy - useful in identifying metastases and assessing response to treatment
• Genetic studies- looking at chromosomes 11 and 22
• Biopsy of tumour site
• Bone marrow aspiration.

Staging of the tumour is undertaken to determine the treatment and also give some indication of the likely prognosis:

• Stage 1A - Low grade tumour found only within the hard coating of the bone
• Stage 1B - Low grade tumour extending locally into the soft tissues
• Stage 2A - High grade tumour found only within the hard coating of the bone
• Stage 2B - High grade tumour extending locally to the soft tissues
• Stage 3 - Low or high grade tumour which has metastasised.

Non-Drug

• The family of a child with Ewing sarcoma will require long term support from a number of professionals in both primary care and the hospital setting. It is important that all members of the family know where to access information, support and practical help when required, and it is vital that there is good communication between all professionals involved in the care of the child.
• Radiotherapy may be used in conjunction with surgery and/or chemotherapy. Radiotherapy may occasionally be used in place of surgery where removal of the bone is not possible e.g. in the spine.
• Peripheral blood stem cell harvest may be undertaken midway through chemotherapy. The recovered cells are stored in case of future need following further courses of chemotherapy.
• Physiotherapy ±/ prosthetic limb fitting may be required following surgery.

Drugs⁵

Chemotherapy is usually the first line of treatment and is currently initiated using a combination of vincristine,ifosamide, doxorubicin and etopiside (VIDE).The treatment usually takes the form of 6 courses of treatment at intervals of 3 weeks following which further management decisions will be based partly on the response to treatment. Further courses of chemotherapy using different combinations of drugs are generally used following surgery or radiotherapy.

Surgical

Surgery is often required to remove the tumour. Limb-sparing surgery, where only a part of the bone is removed and replaced if necessary with a segment of prosthetic bone, is increasingly carried out, although amputation of the limb may be required if the tumour is affecting one of the long bones of the arm or leg.

The overall 5 year survival rate for Ewing sarcoma is 66%. The initial response to induction chemotherapy is a good prognostic indicator, those with a good response having a 75% disease free survival at 5 years, and those with a poor response having a disease free survival rate of only 20% at 5 years. Patients with metastases at the time of diagnosis had a worse survival than those that did not, and those with lung metastases did better than those with bone metastases.