Increased risk of pancreatic adenocarcinoma after acute pancreatitis.

BACKGROUND & AIMS: Acute pancreatitis (AP) is often the initial presentation of pancreatic cancer (pancreatic adenocarcinoma [PaCa]). We evaluated the risk of PaCa after AP.

METHODS: We performed a retrospective study of patients with AP who sought care in the Veterans Health Administration from 1998 through 2007. We excluded patients with pre-existing PaCa or recurrent AP and those who had the first episode of acute pancreatitis, from 1998 through 2000.

RESULTS: Of 495,504 patients with Veterans Health Administration inpatient and outpatient records, 5720 were diagnosed with AP (1.15%) and 710 were diagnosed with PaCa (0.14%), from 2000 through 2007. Seventy-six patients had AP within 2 years before being diagnosed with PaCa (10.7% of all patients with cancer diagnosed during that period). The risk for PaCa was greatest in the first year after AP (14.5 per 1000 patient-years) and then decreased rapidly. Risk for PaCa was negligible in patients <40 years old. The incidence of PaCa within the first year after AP was 7.69 per 1000 patient-years in fifth decade of life and reached 28.67 after the seventh decade. Time to diagnosis of PaCa after AP was ≤2 months for 34 patients, 3-12 months for 35 patients, 13-24 months for 7 patients, and >24 months for 10 patients.

CONCLUSIONS: A significant number of patients with PaCa initially present with AP; the diagnosis of cancer is often delayed by up to 2 years. We suggest that PaCa be routinely considered as a potential etiology of AP in patients ≥40 years old.