Radiation-induced sarcomas following radiotherapy for breast cancer

Youlia M. Kirova, M.D., Frank Feuilhade, M.D., Ph.D., Elie Calitchi, M.D., Yves Otmezguine, M.D., Jean P Le Bourgeois, M.D.

Service de Radiothérapie, Centre Hospitalo-Universitaire Henri Mondor, Assistance Publique -Hôpitaux de Paris, Créteil, France

Aim : to report our experience in the diagnosis and treatment of radiation-induced sarcomas following radiotherapy (RT) for breast cancer. Methods : Ten patients with radiation-induced sarcomas following radiotherapy for breast cancer have been treated in our Department between 1983 and 2000. All of them fulfilled the criteria established by Cahan et al. : 1- prior history of RT ; 2- asymptomatic latent period of several years ; 3- the occurrence of a sarcoma within a previously irradiated field ; 4- histological confirmation of sarcomatous nature of the post-irradiation lesion. Patients were treated for their breast cancer between 1974 and 1989 with a cobalt unit or 4 MV linear accelerator : two opposed tangential portals were used to deliver a dose of 45 Gy in 5 weeks to a reference isodose along the chest wall. The supraclavicular and axillary lymph nodes received 45 Gy to chosen reference points. A supplementary dose of 15 Gy was given to the internal mammary nodes and axilla, using a direct 10 or 13 MeV electron beam. Finally, the tumor site received an additional 15-25 Gy using 192 Ir low dose rate afterloading interstitial technique or electrons. Results : All 10 patients underwent surgery and radiation therapy for their breast cancer. Only two patients received chemotherapy. All patients at the time of diagnosis of RIS were free of disease. Radiation-induced sarcoma appeared with a latency period varying from 5 years to 18 years. The patients age ranged from 39 to 88 years. The histological types of RIS were : angiosarcoma, fibrosarcoma, osteosarcoma, malignant fibrous histiocytoma (MFH), and highly malignant undifferentiated sarcoma. All patients received treatment for their sarcoma. Updated results regarding time-to-event variables will be presented at the meeting. Conclusions : Our series confirm that radiation therapy can induce malignancies after a latent period of several years. Radiation-induced sarcomas are associated with poor overall prognosis. The management, some radiobiological problems, and prognosis will be discussed.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Carcinogenesis.