Oncology, Undernutrition and Sensoriality: Links, Mechanisms and Levers for Action

Cancers of the upper aerodigestive tract account for around 4% of all malignant tumours worldwide. Colon and liver cancer are the most common digestive cancers. The epidemiology of liver cancer is changing, and the number of deaths from liver cancer has increased by 25% worldwide. In France, around 19,000 cancers of the upper aerodigestive tract and 88,000 new cases of digestive cancer are diagnosed each year (colon cancer remains the most common). Patients with these two types of cancer are at particularly high risk of undernutrition. In cancer patients, changes in diet may result from constraints linked to the cancer or possible after-effects, but also from personal choices (for example, adopting a healthier diet). Cancer and its treatment lead to changes such as increased nutritional requirements and hypercatabolism, or sensory changes (taste and smell), reducing pleasure and food intake. These problems will impair quality of life and intensify undernutrition, a major problem in the management of the disease since it increases the risk of complications, therapeutic failure and mortality. It is estimated that 10-20% of deaths in cancer patients are attributable to the consequences of undernutrition rather than to the disease itself. In the VICAN study, 41% of patients changed their diet after diagnosis: 29% because of changes in taste and 82% to have a healthier diet. These changes were associated with the treatment received, the presence of sequelae and anxiety. Taste and smell disorders are common in different types of cancer (any solid or haematological type) and treatments (chemotherapy, radiotherapy and surgery. The mechanisms involved in sensory changes are not fully understood, especially in cancer, and with different types and treatments. Several hypotheses have been proposed: altered expression of enzymes of the oral sphere, altered expression of sensory receptors, saliva composition and function, and impact of the oral microbiota. The early identifica