[Principles and 1977 concept of cancer multistep therapy. Physiological fundamentals of the new timing. Selectotherm local hyperthermy (author's transl)].

A report is given on the further development of the Cancer Multistep Therapy (CMT) Concept. With a clinically applied blood glucose concentration of 5 . 10(-3) g ml-1 the pH value in tumour tissue reduces to about 6.0 which, in turn, causes an increase in thermal sensitivity of cancer cells by approximately 2 degrees C. At the same time, their proliferation ceases almost completely. In addition, the pH value at the venous end of capillaries in tumour tissue increases to about 6.5 so that the flexibility of the erythrocytes gets lost in a selective mode. From this it follows that, under CMT conditions, there will be a total decrease of microcirculation in tumour tissues. All the aforementioned facts have been considered by a new timing: applying cancerostatic drugs and/or ionizing radiation prior to the said drop of microcirculations and of cancer cell proliferation rate. The begin of the hyperthermy step is then planned to take place immediately after the decrease of microcirculation in tumour tissue since the action of the discussed local hyperthermy then becomes very strong (pronounced selective reduction of convection cooling by the blood stream; further enhanced thermal sensitivity of cancer cells). Local hyperthermy then is performed by superposing the Selectotherm Process on 40 degrees C whole-body hyperthermy which allows high power densities also with deep-seated tumour tissues. Finally calculated temperature profiles in tumour tissue of various diameters are discussed together with the practice-considered parameters used in the respective equations.