It is important to understand that surgical margins are not always assessed at the time of surgery at many cancer centers; there are studies that are often debated in the surgical community which do not show a difference in recurrence due to a positive margin. It is very surgeon-specific. At Mayo Clinic, we do assess margins in the operating room as we feel it is important to ensure all the cancer has been removed. This is done as a frozen assessment, and it is done by review by a trained pathologist looking at the margins. This is highly accurate but not always perfect and may change when the final pathology is determined 3-5 days after surgery. This has also been looked at extensively in the literature. However, as previously mentioned, most patients recur with disease outside of the pancreas, likely due to small cancer cells that had already been released into the blood stream before surgery. This is why chemotherapy is such an important part of treatment for pancreatic adenocarcinoma, whether or not a patient has surgery. This is also why some centers do not check intraoperative margins – it is not clearly known if disease that is left behind contributes to distant recurrence.