Integrating evolutionary dynamics into cancer therapy

Most systemic cancer therapies are administered at doses at or close to the maximum tolerated dose until disease progression. However, this approach usually leads to treatment resistance and fails to take into account several potentially relevant evolutionary principles. In this Review, the authors describe how existing approaches to cancer therapy might be optimized by incorporating an understanding of evolutionary dynamics into cancer therapy. Many effective drugs for metastatic and/or advanced-stage cancers have been developed over the past decade, although the evolution of resistance remains the major barrier to disease control or cure. In large, diverse populations such as the cells that compose metastatic cancers, the emergence of cells that are resistant or that can quickly develop resistance is virtually inevitable and most likely cannot be prevented. However, clinically significant resistance occurs only when the pre-existing resistant phenotypes are able to proliferate extensively, a process governed by eco-evolutionary dynamics. Attempts to disrupt the molecular mechanisms of resistance have generally been unsuccessful in clinical practice. In this Review, we focus on the Darwinian processes driving the eco-evolutionary dynamics of treatment-resistant cancer populations. We describe a variety of evolutionarily informed strategies designed to increase the probability of disease control or cure by anticipating and steering the evolutionary dynamics of acquired resistance.