Tighter resection cutoff may be helpful in small pancreatic tumors

Last Updated: 2015-12-08

By David Douglas

NEW YORK (Reuters Health) - In patients with small nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) on pretherapeutic imaging, a 1.7 cm cutoff for resection might increase the prognostic value of indicators of malignancy, according to French researchers.

As Dr. Nicolas Regenet told Reuters Health by email, in such tumors "size is among the most commonly available predictive factors for malignancy and it appears that a cutoff at 1.7 cm could be used to predict malignancy."

PNETs account for only 5% of pancreatic cancers, Dr. Regenet of Institut des Maladies de l'Appareil Digestif (IMAD) in Nantes and colleagues note in Surgery, online November 14. And NF-PNETs, which are defined by an absence of symptoms related to secretion of neuroendocrine peptide, account for about half of all PNETs.

Although PNETs have a much better prognosis than pancreatic adenocarcinoma, with a five-year survival rate of 48%, that for NF-PNETs is only 31%.

Improved imaging is increasingly allowing diagnosis at a small size, but there is no clear consensus on management. Some research suggests operative resection and some close monitoring.

To gain further information, particularly given the high risk of such procedures, the team retrospectively examined outcome in 66 patients with a mean tumor size of 1.6 cm who underwent operative resection. A further 14 with a mean tumor size of 1.4 cm had observational follow-up alone.

Overall, 15 patients (19%) had malignant tumors defined by node or liver metastasis. Two-thirds of these were diagnosed incidentally. Median disease-free survival was 16 months with malignant tumors and 30 months with non-malignant tumors.

Tumor size had a significant association with malignancy; using a cutoff of 1.7 cm, rather than the widely used 2 cm, predicted malignancy with a sensitivity of 92% and a specificity of 75%.

"Tumor size is among the most commonly available predictive factors for malignancy; a cutoff at 1.7 cm could be used to predict malignancy," the team writes.

Given these findings, Dr. Regenet added that "surgeons must select patients for resection carefully, particularly in case of tumor of the pancreatic head, which requires pancreatoduodenectomy."

SOURCE: http://bit.ly/1lqomSX

Surgery 2015.