In France, undernutrition affects almost three million people, a third of whom are over 70 (Diagnosing undernutrition earlier in the elderly aged 70 and over, n.d.). In fact, 30 to 70% of hospitalized elderly patients suffer from protein-energy undernutrition (denutrition_personne_agee_2007_-_recommandations.pdf, n.d.).

The Nutricancer 2 study published in 2014, demonstrated that undernutrition is common among cancer patients. Indeed, 39% of patients suffer from undernutrition and its prevalence depends on the type of cancer, with a predominance of esophagus, stomach and pancreas (60% to 66%), colon/rectum, ovary/uterus and lung (39% to 45%), hematological malignancies (34%), as well as prostate and breast (13% to 20%) (Hébuterne et al., 2014). Moreover, over the past 30 years, undernutrition has been observed in 30% to 50% of the population at the time of diagnosis and before the start of cancer treatment (Boranian et al., n. d.).

Undernutrition is often associated with several terms such as malnutrition, anorexia, sarcopenia or cachexia, which refer to geriatric or metabolic syndromes of multifactorial origin that sometimes overlap, and are often observed in cancer patients. Cancer cachexia is a metabolic syndrome associated with undernutrition of multifactorial origin (Boranian et al., n.d.). Its prevalence is around 50% to 80% in cancer patients and is an independent indicator of morbidity and mortality in this population (Nicolini et al., 2013).

Undernutrition is a major health issue in elderly cancer patients. It is therefore crucial to diagnose it early, given its high prevalence in this population and the serious complications it can lead to. In 2021, the HAS updated its recommendations on the diagnosis of undernutrition in the elderly. The diagnosis of severe undernutrition is based on several criteria, including serum albumin levels. This is a commonly used marker of nutritional status, especially in patients with involuntary weight loss. However, it is important to note that hypoalbuminemia can be observed in many pathological conditions, including inflammatory syndromes common in cancer. Therefore, interpretation of albuminemia results must take into account the patient's inflammatory status, assessed by C-reactive protein. This analysis makes it possible to distinguish undernutrition due to insufficient food intake from that associated with an inflammatory syndrome and hypercatabolism (Patry & Raynaud-Simon, 2010).

Inclusion Criteria:

• Patients aged 70 and over with a diagnosis of moderate or severe undernutrition
• All patients with diagnosed cancer and ongoing cancer treatment.

Exclusion Criteria:

• Patients under 70 years of age
• Hospitalized patients no longer undergoing anticancer treatment
• All patients undergoing pre-habilitation for surgery

The population of this study will be made up of oncogeriatric patients aged 70 and over, hospitalized in the USSROG unit with a diagnosis of undernutrition and undergoing anticancer treatment.