Prevalence of colorectal cancer in cryptogenic pyogenic liver abscess patients. Do they need screening colonoscopy? A systematic review and meta-analysis

Background: Cryptogenic pyogenic liver abscess (PLA) could result due to compromised colonic mucosal barrier in patients with colorectal cancer (CRC). Association of PLA and CRC is unclear. Evidence is weak and limited to small sized studies. As a result, the need for colonoscopy in PLA patients is debatable. Methods: We conducted a comprehensive search of multiple electronic databases and conference proceedings (from inception through January 2019) to identify studies that reported on the prevalence of CRC in PLA patients. Our goals were to evaluate the pooled rate of CRC in patients with cryptogenic PLA. Results: 12 studies were included in the analysis. 18,607 patients were diagnosed with PLA in study group and 60,130 patients were in control group. 63% were males in the age range of 56–94 years. 90.5% of the colonic lesions were left sided and 93.1% were positive for Klebsiella pneumoniae. The pooled rate of prevalence of CRC was 7.9% (95% CI (confidence interval) 5–12.1, I² = 92.4, relative risk = 6.6) in patients with PLA, as compared to 1.2% (95% CI 0.3–5.7, I² = 93.4) in control, with statistical significance (p = 0.001 respectively). Conclusion: Our study, albeit limited by heterogeneity, demonstrates that patients with cryptogenic PLA are at a 7-fold risk of having CRC. A screening colonoscopy may be considered in population with cryptogenic PLA, especially if positive for K. pneumoniae. Well-conducted studies are needed to answer this question.