Proposed Liver Debulking Criteria for PNETs Could Improve Survival

Researchers are proposing the consideration of expanding criteria for liver debulking in pancreatic neuroendocrine tumors (PNETs) to include a threshold of greater than 70% debulking, intermediate grade tumors, positive margins, parenchyma-sparing resections, and extrahepatic metastases.

“These criteria yield results indistinguishable from complete resection,” wrote Rosemary E. Morgan, MD, of Oregon Health & Science University, and colleagues in a study published in the journal Surgery.

According to the study, PNETs are rare cancers that frequently metastasize to the liver, and the most common cause of death in patients with liver metastases is liver failure. Debulking neuroendocrine liver metastases may improve survival for patients with PNETs.

In a recent series of patients with carcinoid liver metastases, including a small number of patients with PNETs, Morgan and colleagues explored decreasing the liver debulking threshold from 90% to 70%. 

“Five-year survival was 90%, and there were no differences in liver progression or survival according to percent of hepatic disease resected,” the researchers wrote. “Furthermore, there were no differences in outcomes based on metastasis size, number, grade, or presence of extrahepatic metastases.”

In this study, the researchers reviewed the use of liver debulking with a threshold of 70% in 42 patients with PNETs who underwent surgery from 2006 to 2016.

The 42 included patients underwent 44 operations; 24 resulted in 100% debulking, 12 in 90% or greater debulking, and 8 in 70% or greater debulking. With a median follow-up of 33 months, the median progression-free survival for the group was 11 months and the 5-year overall survival was 81%.

No significant differences in outcomes were found based on the percent debulked. Only liver metastasis of 5 cm or greater was associated with liver progression-free survival (P = .003) and overall survival (P = .04).

“The results of the present series show that on both univariate and multivariate analyses, patients had outcomes that were indistinguishable based on percentage of gross hepatic disease debulked, providing additional support to extend the threshold of 70% for debulking to PNET liver metastases,” the researchers wrote.