Brazil has a complex situation in cancer treatment services. The incidence rates have reached around 600.000 new cases each year. The development of an Oncology Decision Support System (ODSS) that support cancer treatment is amongst the priorities in the cancer control program. The purpose of this article is to study the ODSS deployment at the Brazilian National Cancer Institute. The implementation of this Clinical Decision Support System employed on the management, processing, and analysis of Brazilian cancer clinical data can be considered a disruptive innovation which changes the clinical decision-making process radically.