Rare tumours of the pancreas: monocentric study.

Purpose: The biology of rare pancreatic tumours, which differs from that of ductal pancreatic cancer, requires increased attention. Although the majority of rare pancreatic tumours are benign, it is difficult to decide whether an invasive component exists without complete removal of the lesion, despite considerable progress in diagnosis. We are investigating a large cohort of patients with histologically confirmed epithelial non-ductal non-neuroendocrine neoplasms of the pancreas.

Methods: Here we analyze long-term survival from patients, who underwent resection of histologically confirmed epithelial non-ductal non-neuroendocrine neoplasms of the pancreas. At our department between Jan 1st, 1999, and Dec 31st, 2019. The median follow-up was 61 (range 0-168) month. All statistical analyses were performed using SPSS 26.0 (IBM, Chicago, IL, USA) software.

Results: 46 patients (48%) were followed up for more than 5 years, 18 patients (19%) for more than 10 years. The 5-year and 10-year survival rates for rare non-invasive pancreatic tumours were 72% and 55% respectively. The proportion of rare tumour entities (non-ductal and non-neuroendocrine) increased continuously and statistically significantly (p = 0.004) from 4.2 to 12.3% in our clinic between 1999 and 2019. If there is no invasive growth yet, there is a varying risk of malignant degeneration in the course of the disease. Therefore, the indication for pancreatic resection is still the subject of discussion.

Conclusion: The long-term prognosis of rare epithelial pancreatic tumours after R0 resection-even if they are already malignant-is much better than that of ductal pancreatic cancer.