Harindra Jayasekara1,2, Jeanette C Reece1, Daniel D Buchanan1,3, Dennis J Ahnen4, Susan Parry5, Mark A Jenkins1, Aung Ko Win1. 1. Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia. 2. Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia. 3. Colorectal Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia. 4. Department of Medicine, University of Colorado School of Medicine, Denver, Colorado, USA. 5. New Zealand Familial Gastrointestinal Cancer Service, Auckland, New Zealand.
Abstract
BACKGROUND AND AIM: We conducted a systematic review and meta-analysis to identify personal, lifestyle, and tumor-related risk factors for metachronous colorectal cancer (CRC) and polyp. METHODS: Relevant studies were identified by searching MEDLINE, Web of Science and Cochrane Central Register through 15 May 2016. Estimates for associations were summarized using random effects models. RESULTS: Fifty-five studies were included in the review. For individuals who had a CRC resection, having a synchronous polyp was a risk factor for metachronous CRC or polyp (relative risk [RR], 2.04; 95% confidence interval [CI], 1.48-2.82) and having a synchronous CRC (RR, 1.90; 95% CI, 1.25-2.91) and proximally located CRC (RR, 2.12; 95% CI, 1.24-3.64) were risk factors for metachronous CRC. For individuals who had a polypectomy, larger size (RR, 4.26; 95% CI, 2.11-8.57) or severe dysplasia of the initial polyp (RR, 5.15; 95% CI, 2.02-13.14), and having a synchronous polyp (RR, 2.52; 95% CI, 1.35-4.73) were risk factors for metachronous CRC; and a family history of CRC (RR, 1.90; 95% CI, 1.26-2.87), having a synchronous polyp (RR, 2.47; 95% CI, 1.74-3.50) and a larger size (RR, 1.49; 95% CI, 1.03-2.15) and proximal location of the initial polyp (RR, 1.20; 95% CI, 1.02-1.40) were risk factors for metachronous polyp. Meta-regression showed duration of follow-up was not a source of heterogeneity for most associations. There was no evidence that lifestyle factors were associated with metachronous CRC or polyp risk. CONCLUSION: A comprehensive list of risk factors identified for metachronous CRC or polyp may have important clinical implications.
BACKGROUND AND AIM: We conducted a systematic review and meta-analysis to identify personal, lifestyle, and tumor-related risk factors for metachronous colorectal cancer (CRC) and polyp. METHODS: Relevant studies were identified by searching MEDLINE, Web of Science and Cochrane Central Register through 15 May 2016. Estimates for associations were summarized using random effects models. RESULTS: Fifty-five studies were included in the review. For individuals who had a CRC resection, having a synchronous polyp was a risk factor for metachronous CRC or polyp (relative risk [RR], 2.04; 95% confidence interval [CI], 1.48-2.82) and having a synchronous CRC (RR, 1.90; 95% CI, 1.25-2.91) and proximally located CRC (RR, 2.12; 95% CI, 1.24-3.64) were risk factors for metachronous CRC. For individuals who had a polypectomy, larger size (RR, 4.26; 95% CI, 2.11-8.57) or severe dysplasia of the initial polyp (RR, 5.15; 95% CI, 2.02-13.14), and having a synchronous polyp (RR, 2.52; 95% CI, 1.35-4.73) were risk factors for metachronous CRC; and a family history of CRC (RR, 1.90; 95% CI, 1.26-2.87), having a synchronous polyp (RR, 2.47; 95% CI, 1.74-3.50) and a larger size (RR, 1.49; 95% CI, 1.03-2.15) and proximal location of the initial polyp (RR, 1.20; 95% CI, 1.02-1.40) were risk factors for metachronous polyp. Meta-regression showed duration of follow-up was not a source of heterogeneity for most associations. There was no evidence that lifestyle factors were associated with metachronous CRC or polyp risk. CONCLUSION: A comprehensive list of risk factors identified for metachronous CRC or polyp may have important clinical implications.