Metastasis as a beneficial process.
The most important message to be found in the "Fourth report on end results in cancer" in the U.S., states that with the progression of cancer, its force of mortality declines. This has been reexamined in the present study. The declining force of mortality implies that as the disease advances the chances of the average patient to survive, improve. Since in the cancer patient all vital functions gradually deteriorate, and the only process gaining with time is his tumor load, one has to consider the possibility that the improving chances of the cancer patient could be linked with the amount of tumor mass in his body. These ideas are illustrated by the following example. Cancer could result from a gradual loss of a vital tissue product 'A', to be replaced by an analogous tissue product 'B' which is of embryonal origin. In the adult, 'B' is produced by stem cells which gradually adapt to the loss of the primary product and increase in number. 'B' is less efficient than 'A' to meet the necessary vital functions. Its deficiency in quality is however augmented by quantity. In order to keep up with the increasing demand, the stem cells proliferate and spread throughout the organism where each metastasis continues to secrete 'B'. The penalty inflicted by this compensatory mechanism is relatively high. Some metastases hit vital functions, and the increasing tumor load depletes the available energy sources. The net effect however is beneficial since without metastasis the organism would have succumbed to the disease in its earliest stage.
D000222:Adaptation, Physiological; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000401:mortality*; D011379:Prognosis