Progresses in cancer treatment transformed cancer into a chronic disease associated with growing nutritional problems. Poor nutritional status of cancer patients worsens morbidity, mortality, overall cost of care and decreases patients' quality of life, oncologic treatments tolerance and efficacy. These adverse effects lead to treatment modifications or interruptions, reducing the chances to control or cure cancer. Implementation of an interdisciplinary and longitudinal integration of nutritional care and nutritional information into cancer treatment (The OncoNut Program) could prevent or treat poor nutritional status and its adversely side effects.