Cardiac radiation-induced sarcomas: A SEER population-based study and a literature review

The aim of this study was to better understand the incidence and the clinical characteristics of cardiac radiation-induced sarcomas (RIS).

We used the surveillance, epidemiology, and end results (SEER) program cancer registry data, the largest cancer database in the United States in order to identify all cardiac RIS between 1973 and 2015. We relied on the Memorial Sloan-Kettering Cancer Center (MSKCC)-modified 1948 Cahan criterions for RIS identification.

Out of 8,136,951 cancer patients from the SEER database, we identified 448 patients diagnosed with cardiac sarcomas. Of these 448 cardiac sarcoma patients, two were considered to have developed a cardiac RIS: a metastatic rhabdomyosarcoma occurring after one to two years following lung carcinoma irradiation, and a soft tissue sarcoma (of unspecified type) developed six years after radiation therapy for an aggressive left-sided breast carcinoma. Based on this observation, we estimated that cardiac RIS represented about 0.4% (95% CI 0.1%-1.6%) of all cardiac sarcomas. A literature review has been conducted and yielded three additional cases of cardiac RIS.

Cardiac RIS are extremely rare malignancies, associated with a very pejorative prognosis. The two reported histologies are angiosarcomas and rhabdomyosarcomas, which might be over-represented among cardiac RIS. A metastatic evolution is possible for cardiac radiation-induced rhabdomyosarcomas. Surgical excision, when feasible, is a therapeutic option and is the only specific treatment reported to this date.