Radiation-induced sarcoma: A single center experience with 36 cases

Abstract

20525 Background: Radiation-induced sarcoma (RIS) is a rare complication of radiation therapy for any cause. With increasing numbers of patients receiving radiotherapy, data concerning the incidence and treatment outcome of RIS are urgently needed. Methods: We screened our local sarcoma registry for patients with RIS. 36 cases of RIS that had developed after radiation for malignant disease were identified and analyzed retrospectively over a 12 year period (1994–2006). Results: All patients had received radiation therapy between 1968 and 2002. The most frequent primary tumors were breast cancer (n = 19) and lymphoma (including Hodgkin`s and non-Hodgkin`s lymphoma, n = 9). The remainder received radiation therapy for tumors of the female reproductive organs (n = 2), head and neck cancer (n = 4), neuroblastoma (n = 1), and seminoma (n = 1).The median of delivered total radiation dose per patient was 50 Gy (35 to 72 Gray). Sources of irradiation were photons (n = 9), cobalt (n = 6), electrons (n = 2), and unknown in 19 cases. The median time interval from the start of irradiation the detection of the sarcoma was 11 years (1 - 35 years). The tumors arose within the radiation field in 29 cases, on the border of the field in 6 cases, and out of field in 1 case. The histology of RIS was angiosarcoma in most cases (n = 12), followed by pleomorphic sarcomas (n = 11), leiomyosarcoma (n = 4), fibrosarcoma (n = 2), osteosarcoma (n = 2), and others (n =5). Most cases were detected in a localized stage of disease (n = 33), and therefore, complete surgical removal was achieved in almost 50% (n = 17). However, this did not translate into long term survival within the overall study population. Only 11 patients remain free of disease during a mean follow-up period of 29 months (range, 0 - 51). Conclusions: Angiosarcomas within or on the border of the radiation field are the most common histological subentity of RIS. Therefore, follow-up of previously irradiated patients should include examination of irradiated regions with a high level of suspicion if cutaneous atypical vascular lesions are found. However, the clinician should be aware of the fact that RIS also occurs out of field and can be of non-angiogenic subtype as well. As far as treatment is concerned, RIS is treated the same as non-radiation induced sarcoma. No significant financial relationships to disclose.