A cohort study in the nutrition unit at Toulouse University Hospital shows that 3 months and 1 year after surgery, there are 2 phenotypes of patients. The first one is called 'little loss' and is defined by a contribution of muscular weight lower than 15% of the total weight loss. The other one is called 'big loss' and is defined by a contribution of muscular weight higher than 15% of the total weight loss. Causes of these different phenotypes are unknown for the moment.