Su1674 Incidence of Colonic Neoplasia in Patients With Breast Cancer: Updated Systematic Review and Meta-Analysis

Abstract

Su1674 Incidence of Colonic Neoplasia in Patients With Breast Cancer: Updated Systematic Review and Meta-Analysis Jennifer H. Lai, Gavin Park, Lauren B. Gerson* Gastroenterology, California Pacific Medical Center, San Francisco, CA; Internal Medicine, California Pacific Medical Center, San Francisco, CA Background: Patients with breast cancer are advised to undergo screening for colon cancer every 5 years due to a perceived increase in cancer risk. Methods: We searched Pubmed (1970-2014) and Cochrane Central Registry of Clinical Trials and included the following search terms: “colorectal neoplasms,” “genes, BRACA1”, “genes BRCA2,” “breast neoplasms,” as well as title words “breast and colorectal” with text word “screening.” The initial analysis included cohort studies that assessed prevalence of colorectal cancer (CRC) in patients with breast cancer. Subsequent analysis focused on case-control studies that assessed prevalence of advanced colonic adenomas and/or cancer in patients with breast cancer. We used Comprehensive Meta-Analysis (CMA, Version 3, Biostat, Inc) to perform the statistical analysis including construction of Forest plots, and assessment of heterogeneity and/or publication bias. For cohort studies, results were reported as pooled prevalence rates with 95% confidence intervals (CI). We determined odds ratios (OR) for casecontrol studies using random effects modeling. Subjects with a diagnosis of breast cancer who had undergone subsequent screening colonoscopy examinations after the initial cancer diagnosis were included. Results: The search yielded 93 articles. We included 30 cohort studies and 9 case-control studies in the analysis. The 30 cohort studies included 2,228,229 patients with breast cancer of whom 21353 (0.9%) developed subsequent colorectal cancer. The pooled prevalence rate of CRC was 0.9% (95% CI 0.7-1%, pZ0). There was significant heterogeneity between studies (IZ99%, pZ0.0) but no evidence of publication bias. In the 4 case-control studies (including 17,827 breast cancer patients and 70,242 controls) reporting numbers of patients subsequently diagnosed with CRC, a non-significant increase in CRC was reported for breast cancer patients (OR 1.2, 95% CI 0.4-3.3, pZ0.7). There were 4 case-control studies assessing risk of adenomatous polyps (including 610 patients with breast cancer and 882 controls) demonstrating an increased risk of advanced adenoma that was not statistically significant (OR 1.8, 95% CI 0.9-3.8, pZ0.08) with moderate heterogeneity between studies (IZ70%, pZ0.003) There was insufficient data to perform subgroup analyses on the usage of tamoxifen and subsequent CRC risk or mean patient age for cases compared to controls. Conclusions: The overall rate of colorectal cancer did not appear to be increased in patients with breast cancer. Colorectal cancer screening in these patients should occur according to current society guidelines.