Due to recent fundamental discoveries, the concept of carcinogenesis, the development of metastatic disease, the patterns of a recurrent malignant process, and the mechanisms involved in the development of resistance has undergone considerable changes. The pooled currently accumulated information allow one to confidently assert that cancer progresses due to the emergence of clones owing to oncogene mutations or epigenetic modifications recorded in the stem cells. The understanding of dormancy, which has become accessible in oncology, the disclosure of its mechanisms, and the role of the inflammatory microenvironment must make a considerable contribution to the development of effective systemic therapy.