POST-RADIATION SARCOMA OF BONE - REVIEW OF 78 MAYO-CLINIC CASES

Abstract

Postradiation sarcoma of bone is an uncommon but serious sequela of radiation therapy. Seventy-eight Mayo Clinic [Rochester, Minnesota, USA] patients were treated for sarcomas arising in irradiated bones. They received their initial radiotherapy for a wide variety of nonneoplastic and neoplastic conditions, both benign and malignant. Thirty-five sarcomas arose in bone that was normal at the time of radiotherapy; 43 arose in irradiated preexisting osseous lesions. The latent period between radiotherapy and diagnosis of sarcoma averaged 14.3 yr. Ninety percent of the postradiation sarcomas were osteosarcomas or fibrosarcomas; chondrosarcoma, malignant (fibrous) histiocytoma, malignant lymphoma, Ewing''s tumor and metastasizing chondroblastoma also occurred. Prompt radical surgery, when feasible is usually the treatment of choice for the sarcoma. About 30% of patients with sarcomas of the extremities or craniofacial bones survived 5 yr without recurrence; there were no disease-free survivors among patients with tumors of the vertebral column, pelvis or shoulder girdle. The low risk of sarcoma following radiotherapy for the treatment of cancer should not be a contraindication to its use in these patients; radiation therapy for benign bone tumors should be reserved for lesions that are not amenable to surgical treatment. An unusual case is reported in which a fibrosarcoma was discovered in the humerus of a patient who had received radiotherapy 55 yrs previously for a verified osteosarcoma in the same site.