The Cancer Care: Treatment Outcomes Ontology (CCTOO) catalogues various clinical endpoints used in evaluating outcomes of cancer treatment. In addition to a vocabulary list, CCTOO also curates the dependencies between individual concepts, in form of production rules, for translating clinical findings recorded in the electronic medical records (EMR) into literature-based concepts. An earlier version of this ontology was presented as a scientific abstract alongside the American Society of Clinical Oncology annual meeting 2017, Chicago, USA (J Clin Oncol 2017; 35 suppl; abstr e18137). Full paper on http://ascopubs.org/doi/abs/10.1200/CCI.18.00026