Validity of the CR-POSSUM model in surgery for colorectal cancer in Spain (CCR-CARESS study) and comparison with other models to predict operative mortality oleh Marisa Baré, Manuel Jesús Alcantara, Maria José Gil, Pablo Collera, Marina Pont, Antonio Escobar, Cristina Sarasqueta, Maximino Redondo, Eduardo Briones, Paula Dujovne, Jose Maria Quintana, on behalf of the CARESS-CCR Study Group