Oh M, et al. - Researchers performed a systematic review and meta-analyses (overall and in subgroups) of BRCA mutation carriers to determine the colorectal cancer risks in these patients. Findings revealed increased risk of colorectal cancer in BRCA1 mutation carriers, but not in BRCA2.

Methods

• Researchers performed a search through PubMed/MEDLINE, Embase, Cochrane, Scopus, and ProQuest Dissertation & Theses.
• They derived pooled estimates of colorectal cancer risk overall and in subgroups defined by mutation type (BRCA1 or BRCA2), cancer type (colorectal or colon cancer), study design (age–sex-adjusted or crude), and method of ascertainment (ascertained or inferred genotyping) by using unadjusted odds ratios (ORs).
• They used random-effect models to assess the links; all statistical tests were two-sided.

Results

• The systematic review included a total of 18 studies, including five cohort studies with ascertained BRCA mutation, six cohort studies involving pedigree analysis, five case–control studies, and two kin–cohort studies.
• The meta-analysis included 14 of these 18 studies and revealed a statistically significant increased risk of colorectal cancer in overall BRCA mutation carriers (OR=1.24, 95% confidence interval (CI)=1.02 to 1.51, P=.03).
• An increased risk of colorectal cancer (OR=1.49, 95% CI=1.19 to 1.85, P < .001) was observed in relation to BRCA1 mutation, but not BRCA2 mutation (OR=1.10, 95% CI=0.77 to 1.58, P=.61), in subgroup meta-analyses by BRCA type.
• BRCA1 carriers had an increased risk of colorectal cancer (OR=1.56, 95% CI=1.23 to 1.98, P < .001), but BRCA2 carriers did not (OR=1.09, 95% CI=0.75 to 1.58, P=.66), as reported in subgroup meta-analyses of studies reporting estimates adjusted for age and sex.
• Data revealed no link between BRCA mutation and colorectal cancer risk in analyses stratified by ascertainment method.