Can the treatment be used for cancers that have metastasized?
Proton therapy benefits patients most when tumors to be treated are solid, have defined borders and are localized, or before the tumor has spread anywhere else in the body. Proton therapys overall benefit is reduced if a cancer has metastasized and spread to other parts of the body. When a large area must be radiated or a tumor is close to the surface of the body, such as in treating breast cancer, or when the whole body is radiated, as in leukemia and most cases of lymphoma, X-rays and other therapies should be considered.
