If we were to summarize the experience of the treatment of cancer by means of either surgery or radiotherapy alone, we would say that surgery is efficient in controlling the accessible localized tumors, especially if they are histologically welldifferentiated; irradiation will control tumors of the radiosensitive type when a cancerocidal dose of irradiation can be delivered to the whole tumorbearing area without destroying the normal tissues. Both surgery and radiation are fraught with many failures in controlling advanced stages of cancer, even when there is a favorable set of circumstances. This is the basis for the need of combined therapies in the treatment of cancer.
In determining a policy of treatment of cancer, there are two fundamental concepts to consider: (1) the natural history of the cancer and (2) the cancer-host relationship in each particular case. These two sets of circumstances will determine the local and systemic aggressivity of a