Prevention of Conversion of Tumor Dormancy into Proliferative Metastases

Late recurrences of cancer are believed to be due to dormant disease that can persist for long periods following apparently successful treatment of a primary tumor. Clinical tumor dormancy thus creates uncertainty for cancer patients and their physicians, who cannot be certain that their cancer will not recur. We have a poor understanding about which individual patients are at risk for cancer recurrence following a period of tumor dormancy. Thus, in spite of the clinical importance of tumor dormancy, much remains to be learned about the mechanisms responsible for induction of, and release from, dormancy. Here we consider the clinical problem of tumor dormancy and discuss evolving ideas of how tumor dormancy and reinitiation of growth may be regulated, both naturally in the body and therapeutically. A better understanding of mechanisms by which dormancy can be regulated may suggest new therapeutic approaches to either eliminate dormant cancer cells or promote the maintenance of dormancy.