Acute pancreatitis as an early sign of pancreatic cancer; a retrospective, matched cohort study.

Background and aims: Pancreatic ductal adenocarcinoma (PDAC) often presents as acute pancreatitis (AP). However, data on the clinical outcomes of PDAC initially presenting as AP are limited. We aimed to assess the clinical features of PDAC that manifest as AP.

Methods: We reviewed the PDAC database at the Asan Medical Center between 2010-2016. Our study included 77 patients with PDAC who presented with AP (PDAC-AP group) and 154 age-gender-matched PDAC patients as controls (PDAC-other group). Patients' demographics, disease characteristics, and outcomes were compared between both groups.

Results: Acute pancreatitis was an initial symptom in 1.12% of the patients with PDAC (77 of 6,821). Approximately 81.8% of the patients had clinically mild pancreatitis, and 91% were diagnosed with PDAC within two months of presentation with AP. Main tumor size was significantly smaller in the PDAC-AP group than in the PDAC-other group (PDAC-AP: 2.59 ± 1.21 cm vs. PDAC-other: 3.73 ± 1.78 cm, p < 0.01). The PDAC-AP group patients were diagnosed earlier than those in the PDAC-other group (PDAC-AP: stage 1-2, 80.6% vs. PDAC-other: 46.7%, p < 0.01). The proportion of resectable PDAC was significantly higher in the PDAC-AP group (PDAC-AP: 64.9% vs. PDAC-other: 50%, p < 0.01). Overall survival was significantly longer in the PDAC-AP group than in the PDAC-other group (30.2 months vs. 19.9 months, p = 0.03).

Conclusions: In patients who presented with clinical AP, PDAC was identified at an earlier stage, and these patients showed better survival rates. These results suggest that AP may be an early sign of PDAC.