DNA damage is one of the most ubiquitous mechanisms of action exploited in cancer therapy. Rapid proliferation rates and the presence of damaging mutations in DNA repair pathway genes make cancer cells highly susceptible to insult to their genomic material, and classic radiation and chemotherapy treatments exploit this weakness. More targeted approaches to induce damage or prevent repair seek to overcome resistance by exploiting new targets. Conversely, DNA damage quantification is crucial to determine potential genotoxicity of new compounds, which is a key concern in assessing their safety profile.