Higher rate of colorectal cancer among patients with pyogenic liver abscess withKlebsiella pneumoniaethan those without: an 11‐year follow‐up study

AIM: Pyogenic liver abscess (PLA) has been reported as an early manifestation of colorectal cancer (CRC) in adults, but few studies have investigated this relationship. It is unclear if patients with Klebsiella pneumoniae PLA are at increased risk of subsequent CRC. Our aims were to estimate the incidence of CRC among patients with PLA and to compare the incidence of CRC between K. pneumoniae PLA and non-K. pneumoniae PLA groups. METHOD: We conducted a retrospective study of patients with PLA diagnosed between 2000 and 2009 at a medical centre in northern Taiwan. CRC status and survival status were determined until December 2010. Incidence data from the general population were retrieved from the Taiwan Cancer Registry. Outcome measures were defined as standardized incidence ratio and the incidence rate per 100,000 person-years. RESULTS: This study included 2294 patients, of whom 1194 (52%) had K. pneumoniae infection. During the follow-up period, 54 (2.3%) patients were diagnosed with CRC, corresponding to an overall incidence rate of 669.1 (95% CI, 490.7-847.6) per 100,000 person-years. The adjusted hazard ratio of CRC was 2.68 times greater for patients with K. pneumoniae PLA than for those with non-K. pneumoniae PLA (95% CI, 1.40-5.11). CONCLUSION: Patients with K. pneumoniae PLA had a significantly higher rate of subsequent CRC than did patients with non-K. pneumoniae PLA. Colonoscopy is recommended to detect occult colonic malignancy in patients with PLA, particularly for patients over 60 years of age and with K. pneumoniae.