BOSTON – Even partial reduction of liver metastases from malignant small bowel neuroendocrine tumors will help symptoms and improve survival, according to James Howe, MD, director of surgical oncology and endocrine surgery at the University of Iowa, Iowa City.
“Hepatic cytoreduction is not just to cut down on hormone production” to relieve carcinoid syndrome symptoms, but also “there seems to be a survival benefit,” he said at the annual clinical congress of the American College of Surgeons.
There was a time when it was thought that at least 90% of liver metastases needed to be removed for patients benefit, but it’s become clear that even clearing 70% will help.
It’s important, however, to use parenchymal sparing techniques such as wedge excision, enucleation, and ablation. “We don’t do a lot of right and left hepatectomies anymore,” because patients often live a long time with the disease, many past 10 years, so the goal is management without undo side effects from aggressive treatment. “The key thing with all patients is to avoid morbidity. These patients are going to live a long time if you do not do very much,” Dr. Howe said.
The general surgical approach is to remove the primary neuroendocrine tumor (NET) plus regional lymph nodes; debulk peritoneal disease; cytoreduce liver metastases, and remove the gallbladder, because many patients go on to somatostatin analogs; in 2 years or so, they’ll develop gallstones.
CT is overall the most useful imaging tool for workup. The terminal ileum is the most common location of small bowel NETs, but often “the primary will not be seen,” so “the main thing I look for is mesenteric lymphadenopathy. Liver metastases are even more suspicious.” PET imaging with gallium-labeled somatostatin analogues is also “very good for determining if a lesion is indeed a NET and to determine sites of distant metastases,” Dr. Howe said.
Suspicious findings are followed by surgical exploration, which he usually does by midline incision, the size of which depends on if hepatic cytoreduction is planned. “It’s critically important to palpate the entire small bowel, or you are going to miss lesions. You can feel them quite easily even if they are just 1 or 2 mm,” he said.
Laparoscopy is an option for quicker recovery and other benefits, but the downside is “you are going to miss multifocal disease if you are using metal graspers to feel the small bowel,” and challenging node resection is impossible. One compromise is to do a small incision of a few inches; “you can actually palpate the small bowel through a small incision, and resect a section of bowel through it,” he said.
He saves systemic therapy for patients who progress despite surgery and somatostatin analogues. Everolimus is an option, but the most promising option is lutetium Lu 177 dotatate (Lutathera),by the Food and Drug Administration in early 2018 for pancreatic and gastrointestinal NETs.