Postradiation malignant fibrous histiocytoma of bone. A clinicopathologic study of 20 patients.

Among the 130 primary or secondary malignant fibrous histiocytomas of bone diagnosed and treated at Memorial Hospital for Cancer and Allied Diseases during the previous half century, 20 (15.4%) arose as a direct consequence of irradiation. This type is the commonest secondary osseous malignant fibrous histiocytoma at this institution. It affects the ilium, the scapula, and the distal end of the femur most frequently, predominantly in patients whose age peaks in the fifth decade of life, when their sarcomas developed. Grounds for the irradiation were either nonosseous conditions (13 patients) or preexistent skeletal lesions (seven patients). Reasons for the incidental bone irradiation included Hodgkin's disease; carcinoma of cervix, breast, or lung; bilateral retinoblastoma, and others; giant cell tumors predominated among the irradiated skeletal lesions. The mean and the median radiation doses were 6,040 and 5,700 rads, respectively. The latent period between irradiation and the appearance of the bone sarcoma ranged from 4 to 47 years with a mean of 16.5 and a median of 14.5 years, respectively. The cumulative disease-free survival rate at 3 years was 58%. Although all patients who received their radiation therapy for a preexistent bone lesion survived, only 27% of patients whose bone was normal at the time of irradiation are alive and well at the 3-year mark.