Significance of the prognostic stratification of extranodal extension in colorectal cancer

A recent analysis from the MPACT trial supported the use of carbohydrate antigen 19-9 (CA19-9) decrease as a predictive marker for survival in patients receiving nab-paclitaxel plus gemcitabine or gemcitabine alone for metastatic pancreatic cancer; however, CA19-9 cannot be used in this capacity for the 15% to 20% of patients who do not produce elevated levels at baseline, leaving fewer tools for predicting outcomes in these patients. Decreases in tumor metabolic activity as measured by positron emission tomography (PET) also predicted longer survival in the MPACT trial. Here we report that tumor metabolic response measured by PET significantly predicted longer survival in patients in the MPACT trial who did not produce elevated CA19-9 at baseline.