If the systemic agent is going to be held, how many days prior to starting radiation therapy should the agent be held and when can it be restarted after radiation? What general principles do you apply to sequencing these such agents with palliative radiation courses (especially for the newer agents without published evidence on radiosensitization)? Are there chemotherapy drugs that should be held (e.g. cisplatin, when giving a hypofractionated course of pallitive radiation (e.g. 20Gy in 5fx)?