Radiation-induced sarcoma of bone: clinical and radiographic findings in 43 patients irradiated for soft tissue neoplasms.

Sarcomas rarely follow irradiation of benign lesions of bone as the dangers of this form of therapy is well recognised. Forty-three patients with soft tissue neoplasms - mainly carcinoma - were irradiated and developed sarcomas in the radiation field. Twenty-four of these patients were seen at this centre in the last decade, a considerable increase compared to earlier years. Radiation osteitis may indicate the nature of the tumour but was only present in 50%. A purely lytic or purely sclerotic pattern was commoner than a mixed lytic and sclerotic appearance. CT scan, bone scan and angiography were helpful in delineating disease but did not assist in diagnosing the type of tumour. A tumour arising within the irradiated field is an indication for biopsy. Prognosis of radiation-induced sarcoma (RIS) remains poor, only five of the 43 patients survived 5 years.