Leukemia and lymphoma
Leukemias and lymphomas comprise a diverse collection of malignancies with unique clinical behavior. Radiation therapy plays an integral role in the definitive, adjuvant, and palliative management of these hematologic malignancies. As opposed to most epithelial and mesenchymal malignancies, hematologic malignancies typically require lower doses of radiation therapy. Most can be controlled with 24–40 Gy, well within the tolerance of most normal tissues. In the palliative setting, exceptionally low doses (e.g., 4 Gy) are often sufficient. This characteristic of hematologic malignancies allows for re-treatment, when necessary, in most circumstances. In this chapter, we will review the major histologic subtypes of hematologic malignancies and discuss the settings where re-irradiation is sometimes encountered in clinical practice.