Efficacy and Safety of a Preoperative Aerobic Exercise Program in Patients With Gastrointestinal Cancer.

Gastrointestinal - origin cancer is one of the most frequent causes of cancer worldwide ; the primary surgical management is the standard treatment, however, the postoperative complications rate could be up to 35% . Patients with gastrointestinal - origin cancer often experience physical deconditioning; this could lead to an increased risk of complications, especially when they require major abdominal procedures. It has been suggested that physical training in the preoperative period could improve their condition, reducing the risk of complications. Although this topic has been investigated, it has not been established yet the best short preoperative aerobic exercise program to enhance the aerobic capacity in patients with gastrointestinal cancer who are going to be to surgical primary management, and consequently, to help patients dealing with the physiological stress involved in a surgical intervention. Main objective: To determine the efficacy and safety of a 4 weeks preoperative exercise program in patients with gastrointestinal cancer scheduled for primary surgery. Materials and methods: This is a Phase II single arm clinical trial that will include patients between 45 and 70 years, with confirmed gastrointestinal cancer (gastric, liver, colon or rectal cancer), scheduled for surgery in 4 weeks or more since recruitment and without electrocardiographic abnormalities. The patients will be selected from the gastrointestinal unit surgical schedule. The eligible patients will be invited to participate and after their agreement to participate and to do the informed consent process, they will be scheduled to the basal assessment. This aerobic capacity assessment will be done with the 6-minute walk test. After the basal measurement, two physical therapists will prescribe an individualized aerobic training program in 3 sessions per week during 4 weeks. Each session will last 50 minutes and will be programmed as follows: * Week 1: heart rate target: 50% of maximum heart rate * Week 2: heart rate target: 60% of maximum heart rate * Week 3: heart rate target: 70% of maximum heart rate * Week 4: heart rate target: 60% of maximum heart rate The aerobic exercise will be carried on a treadmill or in a stationary bicycle, according to the patient's preferences and will be supervised by a physical therapist. The post intervention aerobic capacity will be measured at week 3 and 4 with the 6-minute walk test. The main efficacy outcome will be peak oxygen consumption (VO2 peak) and the safety outcomes will be exercise-related adverse events and the program adherence. This protocol was approved by the Instituto Nacional de Cancerología's Ethical Board.