Cancer patients are a vulnerable group exposed to numerous and serious risks beyond cancer itself. In recent years, the prognosis of these individuals has improved substantially thanks to several advances such as immunotherapy, targeted molecular therapies, surgical techniques, or developments in support treatment. This coincides with the prolonged survival of oncological patients admitted to the ICU due to critical complications, and under the supervision of intensivists. The time has therefore come to revisit the intensive care support of these patients, which poses new professional as well as organizational challenges. An agreement was signed in 2017 between the SEOM and SEMICYUC with the aim of improving the quality of care of cancer patients with critical complications. The initiative seeks to aid in decision-making, standardize criteria, decrease subjectivity, generate channels of communication, and delve deeper into the ethical and scientific aspects of these situations. This document sets forth the most important reasons that have led us to undertake this initiative.