SAN DIEGO – according to a study presented at the annual Digestive Disease Week.
In a retrospective case series of 20 patients, local recurrence was seen primarily in patients who had cold forceps, rather than deeper, excision techniques. However, most patients who had cold forceps resections also remained recurrence-free, said Jonathan Ragheb, MD, a resident physician at the Cleveland Clinic.
Duodenal neuroendocrine tumors are becoming increasingly prevalent, so Dr. Ragheb and colleagues were interested in “seeing what we should do with them when we encounter them in clinical practice – whether it be surgery or endoscopic intervention,” he said.
In an interview, Dr. Ragheb said that he and his colleagues structured the study to answer the question: “What is the impact of the margin status on the recurrence of the tumor?” This relationship is important in guiding neuroendocrine tumor (NET) management, he said. The technique used for NET removal may also have effects on recurrence rates, so Dr. Ragheb and his collaborators were also interested in answering that question.
The investigators looked at patients at two facilities with a histopathologic diagnosis of duodenal NET who had endoscopic tumor resection during 2004-2018. They excluded patients who had cold forceps endoscopic resection (ER) and clear margins, patients who had further surgical therapy, and those who were lost to endoscopic follow-up.
Assessment of resection margin status was performed independently by pathologists at each study center.
“We found that people with clear margins tend not to have any recurrence, and this is over the course of a year to a year and a half of follow-up,” said Dr. Ragheb, adding, “Those patients who did have some positive margins – whether lateral margins or vertical margins – the majority of them did not have recurrence over that time period.” However, 4 of the patients in the 20-patient cohort did have some tumor recurrence, and all of these patients had an incomplete initial resection.
The investigators took a closer look at which resection techniques were most likely to result in clear margins and no recurrences, and they found that deeper techniques were associated with fewer recurrences. These included endoscopic submucosal or mucosal resection and en bloc snare polypectomy; all were associated with fewer recurrences than resections performed with cold forceps biopsy.
In all, 7 patients had clear (R0) margins, while 13 patients had an incomplete (R1) resection from the biopsy. Of the patients who had R1 margins with local recurrence, three had received a cold forceps biopsy. The other recurrence was in a patient who had endoscopic mucosal resection.
“Margin status is not the sole contributor to recurrence rates of these duodenal neuroendocrine tumors,” said Dr. Ragheb, noting that previous work has identified other possible factors, including tumor grade and biology, that can affect recurrence.
Knowledge gaps still exist regarding best practices for biopsy and decision of duodenal NETs, acknowledged Dr. Ragheb. The present study only followed patients for about a year and a half, so longer-term recurrence patterns and their relationship with various resection techniques aren’t known.
“Larger studies considering tumor grading and ER [endoscopic resection] technique are needed to fully elucidate the risk of local recurrences after ER,” wrote Dr. Ragheb and colleagues.
Dr. Ragheb reported no outside sources of funding and no conflicts of interest.