Radiation‐induced osteosarcomas of the calvarium and skull base

Abstract

Although a rare complication of ionizing radiation, radiation-induced osteosarcoma is now more frequently recognized as radiation therapy has become common and cancer survival has increased. To date, publications on radiation-induced osteosarcoma of the cranium are limited to a few small series and case reports. Data from 175 patients with a history of sarcoma of the head at The University of Texas M. D. Anderson Cancer Center from 1975 to 2007 were reviewed to identify patients with radiation-induced osteosarcoma. The diagnostic criteria were: 1) osteosarcoma arose within the previously irradiated field; 2) new sarcoma was histologically distinct from the original neoplasm; 3) no evidence of new sarcoma at the time of radiation; and 4) distinct latency period could be recognized. Frequencies and descriptive statistics were obtained for the various characteristics under study. The authors identified 16 patients with radiation-induced osteosarcoma of the cranium at their institution. The average age at diagnosis was 35 years. The median latency period was 12.5 years. Nine patients had skull base tumors, and 7 had calvarial tumors. Of the 14 patients treated surgically, 86% developed local recurrence. The median survival time was 29 months, and the 5-year survival rate was 29.6%. The authors report the largest series of cranial radiation-induced osteosarcoma. Although radiation-induced osteosarcoma is an uncommon but dire complication of radiotherapy, its incidence will probably increase in the future as the frequency of radiation treatment and cancer survival increase. These tumors are locally aggressive, and despite aggressive surgical and medical management, they have a high rate of local recurrence and mortality.