Patients with advanced gastrointestinal (GI) cancers are very often sarcopenic/malnourished at diagnosis (> 60% of cases) and at high risk of rapid clinical deterioration. These patients have important supportive care needs that represent a major challenge for improving treatment tolerance and patient survival and health-related quality of life (HRQoL).

Malnutrition and sarcopenia (muscle wasting and dysfunction) are associated with an increased risk of death, complications from chemotherapy, infections, emergency procedures and hospitalizations, and increased costs of care. Therefore, malnutrition and sarcopenia represent a major clinical target in GI cancers.

Interventions targeting malnutrition/sarcopenia should be implemented as early as possible in patients' pathways, these syndromes being reversible at early stages but not at late stages.

A multidisciplinary assessment at diagnosis and therapeutic approach combining nutritional support and and adapted physical activity (APA) in addition to anticancer treatments should be systematically implemented in patients with advanced GI cancers.

This type of intervention complies with the standards recommended by the National Cancer Institute (INCa) to promote the practice of physical activity during and after treatment in oncology.

All patients will receive usual care including:

• Chemotherapy at the investigator's choice,
• Outpatient clinical visits according to the regular schedule,
• Tumor evaluation based on tumor marker serum levels, as appropriate, and TAP-CT with intravenous contrast injection every 8 weeks.

Nutritional support will consist of:

• A nutrition assessment by a dietician including a VAS of food intakes at baseline, at W4 and W8 (plus additional visits if required),
• Nutritional intervention according to the Société Francophone de Nutrition Clinique et Métabolisme (SFNEP) guidelines (dietetic counseling for all patients ± oral supplementation, enteral tube feeding, and/or parenteral nutrition).

Physical activity support will consist of physical condition assessed by International Physical Activity Questionnaire (IPAQ), performance status (ECOG PS), resting heart rate and blood pressure, 6-minute walking test (speed, fatigue), handgrip test, chair stand fitness test, get-up and go test, balance in single-leg and bipodal stance.

Inclusion Criteria:

1. Signed and dated informed consent,
2. Age ≥ 18 years (no superior limit),
3. Histologically confirmed (1) non-colorectal cancer (esophagus, stomach, liver/bile ducts, pancreas, neuroendocrine carcinoma) or (2) colorectal with associated risk factors i.e. ECOG PS 2 (defining significant limitation in daily activities), and/or weight loss ≥ 5% in 1 month or ≥ 10% in 6 months (defining malnutrition/HAS 2019),
4. Advanced disease not amenable to surgery, radiation, or combined modality therapy with curative intent (previous resection of primary tumor allowed), treated with first-line chemotherapy for advanced disease (previous [neo]adjuvant chemo[radio]therapy allowed); or resectable/potentially resectable disease receiving a triplet chemotherapy regimen in a peri-operative setting (e.g. FOLFIRINOX, FLOT) (moderate risk at frailty score)
5. Patients able to attend for administration of chemotherapy,
6. Life expectancy ≥ 3 months,
7. Registration in a National Health Care System (Couverture Maladie Universelle [CMU] included).

Exclusion Criteria:

1. Other active non gastro-intestinal cancers
2. Any medical (including psychiatric, musculoskeletal, or neurological) condition contra-indicating exercise practice,
3. Pregnancy or breastfeeding,
4. Protected adults (individuals under guardianship by court order).

Note: participation to another concomitant clinical trial is allowed, but the patient must inform the Investigator and get an authorization from the Sponsor.