Pyogenic liver abscesses associated with nonmetastatic colorectal cancers: An increasing problem in Eastern Asia

AIM: To elaborate the clinicopathologic features of colorectal cancer-related pyogenic liver abscess (PLA). METHODS: Reported cases of colorectal cancer-related PLAs were collected from the literature published up to October 2011 and evaluated for their clinicopathologic features. Data of collected cases included demographics, clinical presentation, microbial findings and treatment. Categorical variables were compared by χ² analysis and continuous variables were evaluated using Student's t test. RESULTS: A total 96 cases of colorectal cancer-related PLA were collected from the previous literature. Most patients (60%) were male and 40% cases occurred in the age group of 61-70 years. Apart from some special types of PLA, there were significant differences in the microbiological spectrum between Eastern Asia and non-Eastern Asian countries, which implied different risk factors and courses of the disease. Gram negative bacteria especially Klebsiella pneumoniae (K. pneumoniae) PLA was predominant in Eastern Asia (80.0%) in contrast to non-Eastern Asian countries (P < 0.01). Meanwhile, most of the Eastern Asian patients exhibited smaller size of liver abscess and atypical presentation. Sigmoid colon and rectum (72.73%) were the main sites of tumor in Eastern Asian patients, whereas tumor sites were uneven among most of the non-Easter Asian PLA patients. CONCLUSION: K. pneumoniae PLA was strongly associated with colorectal cancer, especially those occurring in sigmoid colon and rectum, in elderly Eastern Asian male patients.