Chronic pancreatitis and extra pancreatic cancers- A systematic review and meta analysis

Chronic pancreatitis (CP) is a known risk factor for pancreatic cancer; however its association to extra pancreatic (EP) cancers remains inadequately explored. The aim of this systematic review is to investigate the evidence for CP as a risk factor for developing EP cancers.

Electronic search was conducted on Ovid Medline, EMBASE and Scopus from inception to January 27, 2024 to identify patients with CP who developed EP cancers. Prevalence and incidence of each cancer were calculated where possible from the reported numbers. A random effects meta-analysis was used to pool prevalence, incidence and hazard ratios (HR) of each EP cancer. Heterogeneity was assessed using I². PROSPERO registration: CRD42024543050.

Sixteen (16) studies consisting of 117,163 CP patients met the eligibility criteria. 4015 (3.4%) patients developed 4019 EP cancers. The overall annual prevalence and incidence of EP cancers were 7962 (95% CI 5044-10880) per 100,000 CP patients and 1039 (95% CI 649-1663) per 100,000 person years. Lung cancer had the highest annual prevalence - (1540 (95% CI 667-2413) per 100,000 CP patients) and incidence (260 (95% CI 120-390) per 100,000 person years). The pooled HR were 1.31 (95% CI 1.03-1.66) and 1.58 (95% CI 1.27-1.98) for adjusted lung cancer and crude liver cancer in patients with CP compared to patients without CP, respectively.

Patients with CP have an increased risk of developing EP cancers compared to patients without CP, in particular lung and liver cancer which had the highest relative risk. Shared risk factor modifications, such as smoking cessation and alcohol reduction, could lower the risk of common EP cancers. Further, implementing non-invasive screening measures may aid in early diagnosis in this high-risk group.