Supportive care in geriatric oncology is crucial care that should be proposed from the beginning of cancer treatment. More than the quantity of life, the quality of life is a primary goal when treating cancer in the older patients. An initial assessment of the frailty of the older patients should be carried out. The eight domains requiring in-depth assessment are social environment, functional status, walking and balance, cognition, psychological status, co-morbidity and polypharmacy, nutrition and sensory deficiencies. The alteration of these domains has an impact on the patient's outcome, his quality of life and the tolerance of the treatment. One of the major challenges is to maintain the autonomy of the older patient, which involves preserving his functional status, his neuropsychological state and his nutritional state. Corrective actions for each of the domains must be implemented and must be adjusted throughout the course. It is also important to anticipate risks that may compromise or delay the continuation of anti-tumor treatment such as falls, delirium, organ decompensation, iatrogenic risk and social isolation.