Data from a new study of a large US multi-institutional cohort of patients with pancreatic neuroendocrine tumors (pNETs) suggested that resection with lymphadenectomy should be considered in those with nonfunctional tumors 1.5 cm to 2 cm in size. 

The management of nonfunctional pNETs is controversial, according to the study. These tumors have a relatively low tendency to progress and removal is associated with potential morbidity. In some cases, patients with these smaller tumors are put under observation, while other experts advocate for removal because of malignant differentiation, lymph node metastases, or distant metastasis. 

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To investigate these options further, researchers looked at a group of 989 patients who underwent curative-intent resection for nonfunctional pNETs. Of the 989 patients, 392 patients (39.6%) had tumors 2 cm or smaller.  Of these, 12.8% had lymph node metastases, which were associated with tumor recurrence (hazard ratio, 3.06; P =.026) after surgery. 

Patients with lymph node metastases also had significantly worse recurrence-free survival compared with those patients without lymph node metastases (5-year relapse-free survival of 81.7% vs 94.1%; P =.019). 

Those patients with tumors measuring 1.5 cm to 2 cm had more than twice the incidence of lymph node metastases compared with patients with smaller tumors (17.9% vs 8.7%; odds ratio, 2.59; P =.022).

After resection of their tumors, 8% of patients with tumors 1.5 cm to 2 cm and 4.5% of patients with smaller patients had tumor recurrence. 

“Taken together, patients with NF‐pNETs measuring 1.5‐2 cm should be strongly considered for surgical resection, whereas patients with tumor <1.5 cm may be more appropriate candidates for surveillance,” the researchers wrote. 

Reference

Dong DH, Zhang XF, Poultsides G, et al. Impact of tumor size and nodal status on recurrence of nonfunctional pancreatic neuroendocrine tumors ≤2 after curative resection: a multi-institutional study of 392 cases. [published online September 30, 2019]. J Surg Oncol. doi: 10.1002/jco.25716