Historically, Hodgkin lymphoma (HL) was the first malignant disease that could be cured. In the past century, the first successful outcomes of radiotherapy employing large radiation fields were reported, in particular in patients with limited disease. Even bulky tumors melted away during intense irradiation. One might hypothesize that this can be explained by the radiosensitivity of the few malignant cells in HL (Hodgkin and Reed-Sternberg [H-RS] cells) amidst the majority of nonmalignant surrounding cells in the microenvironment.