Nanomedicines are extensively used to improve the efficacy and reduce the toxicity of (chemo-) therapeutic drugs. Nanomedicines traditionally rely on the “EPR” effect for target site accumulation, which is highly variable, both in animal models and in patients. To tackle heterogeneity in target site accumulation, and to improve the performance and translation of cancer nanomedicines, we are working on systems and strategies to monitor and modulate tumor-directed drug delivery. In the present lecture, several of these strategies will be highlighted, including the use of histopathological biopsy biomarkers and non-invasive imaging for improved nanomedicine translation and treatment.