Introduction PNETs are rare pancreatic malignancies originating from islet cells and exhibit a strong co-occurrence with Diabetes Mellitus (DM), associated with worse survival outcomes. However, studies have yet to delineate the impact of insulin dependent (IDDM) and non -insulin dependent (NIDDM) on poor oncological outcomes.

Methods Utilizing the U.S. Neuroendocrine Tumor Study Group database (1999-2016), we performed a retrospective cohort study of adult patients who underwent primary surgical resection of PNETs. Patients were categorized based on preoperative diagnosis into non-DM, NIDDM, and IDDM cohorts. We used the Kaplan-Meier method and log-rank test to study cancer-specific survival (CSS). Cox proportional Hazards models were used to assess the impact of IDDM on CSS.

Results Of the 1,122 patients included in the analysis, 870 (77%) were non-DM, 168 (15%) were NIDDM, and 84 (8%) were IDDM. The groups were similar in tumor stage and grade. However, they differed in sex, BMI, age, ASA class, tumor location, preoperative HbA1c and serum glucose (p-value <0.05). Patients with IDDM had significantly decreased 5-year CSS compared to patients without IDDM (CSS: IDDM 85%, NIDDM 94%, non-DM 93%, NIDDM + non-DM 93%; P <0.01). On multivariate analysis, IDDM was independently associated with worse CSS (HR 2.27, 95% Confidence Interval 1.15-4.45, P=0.02).

Conclusion Insulin dependence is associated with worse cancer-specific survival in PNET patients following surgical resection compared to PNET patients with NIDDM or without DM.

The authors have declared no competing interest.

This study did not receive any funding

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The protocol for this study was reviewed and approved by Vanderbilt University Medical Center Institutional Review Board, approval number 170730.

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