https://www.selleckchem.com/pr....oducts/wnk-in-11.htm
Overall survival (OS) is considered the standard measure of outcome in oncology. However, considering that resectable pancreatic neuroendocrine neoplasms (Pan-NENs) usually have a long OS, the feasibility of prospective studies is questionable due to a long follow-up period needed. The primary endpoint was to validate the use of disease-specific survival (DFS) as a surrogate measure of OS. The secondary endpoint was to calculate the gain in sample size using DFS instead of OS in hypothetical prospective studies with two parallel group