Prospective Evaluation of a Program for Early Identification of Needs and Multidisciplinary Intervention in Supportive Care in Digestive 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.