Abstract: A method is provided wherein a suspension containing ferromagnetic particles is introduced into a body, and the particles are caused to move towards a tumor and are retained there by a magnetic field. The area of the tumor is exposed to an electromagnetic field to carry out hyperpyrexia of the tumor to a temperature sufficient to kill cancer cells. The contents of the tumor are removed. The condition of a patient's body is monitored during the treatment by determining activity of neutrophils and macrophages. An apparatus is also provided for carrying out the method and comprises an electromagnetic radiation source with emitters, temperature pickups, and a temperature setter connected to inputs of a comparator, a temperature control unit for controlling hyperpyrexia temperature connected to an output of the comparator and forming a signal fed to a control input of the source of radiation.