Colorectal carcinoma in a patient with prior breast cancer: Is there a causal link?

A 70-year-old female patient with prior breast cancer was diagnosed with colorectal carcinoma six years following the original breast referral. The cancers were both discovered at an early stage enabling potentially curative surgery to be performed, with an associated good long-term prognosis. This article explores a range of cancer risk factors associated with lifestyle, genetics and medication to ascertain whether the two primary cancers were independent oncological events, or whether they were related. Factors such as smoking, alcohol consumption, genetic predisposition and the use of contraceptives and Tamoxifen may increase the relative risk for both cancers. Various studies have offered conflicting data regarding the relative risk for developing the second cancer, but long-term cohort studies will continue to add to the evidence base. It is possible that the outcomes of these studies may have implications for the follow up of breast cancer patients within the colorectal cancer screening service.