In children, the most common bone tumours seen are osteosarcoma and Ewing’s sarcoma. Both of these tumours have a male predominance and are rarely seen before puberty.
Osteosarcoma is the most prevalent primary malignant bone tumour in children. It most commonly affects the ends of long bones, for example, the femur towards the knee (50% of cases occur around the knee). Osteosarcoma most frequently occurs in older children and is rarely seen in the under-5 age group.
Ewing’s sarcoma (primitive neuroectodermal tumour) is a rare disease in which cancer cells are found in the bone or in soft tissue (sarcoma). The most common areas in which it occurs are the pelvis, the femur, the humerus, and the ribs. Ewing’s sarcoma occurs most frequently in teenagers.
Signs and Symptoms
Children are often well at presentation, even with the presence of metastases (usually of the lung). The most common presenting problem is persistent bone pain, which is often present before a mass appears. Muscles near the affected area may also become weaker. With Ewing’s sarcoma there is often a large soft tissue mass.
A detailed pre-treatment assessment of the bone and surrounding tissue must be made to establish the extent of local disease particularly if limb-saving surgery is an option. Biopsy is required for full diagnosis. A range of tests, including MRI and CT scans, x-rays, bone or blood marrow tests, and bone scans, are performed to check for disease spread.
Treatment is dependent on the size, site and spread of the disease. Surgery, chemotherapy and radiotherapy can be combined. Full amputation of the affected limb is a possibility in some cases. Replacement of the bone with either prosthesis or bone graft can also be a surgical treatment option.
Both osteosarcoma and Ewing’s sarcoma are difficult to treat but prognosis is improving and in a large number of cases amputation is not necessary as resection of the tumour and endoprosthetic replacement (requiring modification as the child grows) is often possible.