Whether they are the first sign of cancer or aggravate the evolution of a neoplasm already known and treated, renal, hepatic and cardiac failure constitute a vital threat for a patient with cancer and often justifies an admission to intensive care. If the clinical picture can be considered similar in all respects to that of other patients, the neoplasia and its treatments are often responsible for etiological, diagnostic, prognostic and therapeutic particularities that merit being known. So it is in nephrology with the glomerulopathies and thrombotic microangiopathy, in hepatology with veno-occlusive disease and graft versus host rejection, in cardiology with aplastic septic shock, anthracycline myocardial toxicity, cardiac tamponade... the list is far from being exhaustive. We have attempted to clarify certain of these specifities and the diagnostic and therapeutic approach adapted to these situations that are too often the source of errors with serious consequences.