In oncology, the term "big data" broadly describes the rapid acquisition and generation of massive amounts of information, typically from population cancer registries, electronic health records, or large-scale genetic sequencing studies. The challenge of using big data in cancer research lies in interdisciplinary collaboration and information processing to unify diverse data sources and provide valid analytics to harness meaningful information. This article provides an overview of how big data approaches can be applied in cancer research, and how they can be used to translate information into new ways to ultimately make informed decisions that improve cancer care and delivery.