*When irradiating the spleen for metastatic disease, hypofractionation may be employed, whereas with primary H&N cancers may employ hyperfractionation. What is the rationale for this difference?
H&N cancers originating in the mucosa have a high mitotic activity and short intervals between mitotic events. Hyperfractionation attempts to delay mitotic activity and synchronizw cells to most sensitive phases of division to increase cell kill. Hypofractionation provides the opportunity to cause cell death to any malignant cell infiltrating the organ and at the same time giving sensitive cells time to repair.