Local treatment cures about 30 to 40% of cancers, this proportion depending on the follow-up required to establish it. This means that 60 to 70% of the malignant neoplasias are disseminated either perceptibly (leukemias, visible metas- tases) or imperceptibly, forming a 'minimal imperceptible disease', which local treatment leaves, whether it consists of surgery, radiotherapy, or surgery plus radiotherapy. When the neoplastic tissue is voluminous enough to be per- ceptible, cures can be obtained with chemotherapy or chemo- immunotherapy. When the neoplastic disease is imperceptible, made up...