[PET-CT studies of metastasizing cancer of the colon and rectum. Variability of tumor aggressiveness as a micro-evolutionary process of cancer stem cells with predetermined prognosis].

Formation of cancer stem cells which are both rare and variably therapy-resistant marks the beginning of a new disease without precursors. Based on molecular changes, these cells are derived from normal cells and exhibit pre-programmed malignant behaviour. In vitro studies have shown that hybrid cancers which behave in a similar way to Dukes A, B or C cancers in vivo can be produce by horizontal gene transfer. The level of aggressiveness follows a Galton curve in the probability distribution. In the current paper we analyzed colorectal cancers by PET-CT in follow-up studies which extended over several years. We conclude that the primary tumors behave differently from distant metastases. Radical exstirpation of the primary tumor is able to cure the malignant process if the homing area is resected. The primary tumor acts as the supplier of cancer stem cells for metastases which appear in different organs. When chemotherapy is administered the distribution of metastases in different organs appears dependent of the response or non-response of cancer stem cells to this therapy. Large numbers of colorectal carcinomas existed for the same time duration before death (15 years) independent of the malignancy grade. The tumor metastasizes immediately after formation. The primary tumor and the metastases appear variably quickly depending on the malignancy grade and are autonomic processes.