Medical ethics is concerned with practices of care, their purposes, their feasibility. It raises questions about taking care of elderly patients with cancer. The decision criteria of exploration in search of cancer or treatment of confirmed cancer are numerous. Some are medical criteria (benefit on survival, polypathology, impact on the body, the prognosis associated with comorbidities), others are more subjective (quality of life, difficulty of patient's information, longer hospitalisation, ageism). Age appears to be the first lock, the second is cognitive disorders. Overexpenditure of current assumptions seems necessary to improve the care of elderly patients with cancer. Especially since many publications indicate that cancer treatments are generally well supported and beneficial to advanced ages.