Interdisciplinary Treatment and Oncological Outcomes of Resected Pancreatic Neuroendocrine Neoplasia in Austria: A Multicenter Cohort Study under the Auspices of ACO-ASSO

Background:

With an incidence of approximately 1/100.000, pancreatic neuroendocrine neoplasia (pNEN) are rare compared to ductal adenocarcinoma. Due to biological and clinical heterogeneity optimal treatment remains a matter of debate. Surgery is considered the gold standard for resectable disease, whereby definition of resectability has substantially changed with advances in surgical oncology. Furthermore, strategies for subgroups of pNENs might deviate, some authors for example suggesting upfront systemic chemotherapy for G3 tumours or a watch-and-wait-strategy for small tumours. To foster insights in pNENs, Austrian surgical units have joined forces.

Methods:

To date, 7 medium-/high-volume-centres have provided data with individual inclusion periods from 1997 – 2016. Patient demographics, perioperative parameters, adjuvant therapy and oncological follow-up data were analysed.

Results:

In total, 200 patients undergoing resection of pNENs are included, representing 2/3 of all Austrian pNEN resections recently. Data completeness for presented variables exceeds 95%. Postoperative morbidity ranges within international standards with a 90-days-mortality of 4% and 43% overall complications (13% severe). Preoperative diabetes was present in 14%, 13% of patients developed new-onset postoperative diabetes. Lymph-node involvement was present in 17% of G1, 39% of G2 and 43% of G3 tumours. 5- and 10-year overall survival was 81% and 53%, with a 5-year recurrence-free-survival of 70%. Twenty-four percent of patients received adjuvant therapy. Recurrence (24%) most commonly developed in the liver (68%) and locally in the pancreas (30%), 80% received further therapy for relapse. In multivariable analysis, age ≥60 (HR: 3.47), grading (HR: 2.35) and nodal involvement (HR: 2.22) were significantly associated with poor overall survival. Postoperative complications did not influence oncological outcome. Thirty-two percent had tumours < 2 cm, whereby 33% had G2/G3 grading, 12.5% positive lymph-nodes and 5% distant metastasis.

Conclusion:

The ACO-ASSO-registry represents one of the largest European databases of resected pNENs providing details of interdisciplinary care, and serving as vital baseline for future prospective studies in Austria.