Review of the Mechanisms Involved in the Abscopal Effect and Future Directions with a Focus on Thymic Carcinoma

The abscopal effect is a rare phenomenon in radiotherapy, leading to impressive tumor regression outside the radiotherapy field. In this article we describe the occurrence of a postradiotherapy abscopal effect in an 89-year-old patient suffering from a metastatic neuroendocrine large-cell thymic carcinoma, the first case of the abscopal effect related to a thymic carcinoma reported in the literature. Along with the description of this case, we discuss and review the main potential mechanisms of bystander and abscopal effects in solid tumors so as to enable clinicians to identify and control these effects more resourcefully in the age of immunotherapy and stereotactic radiotherapy.