The gut microbiome and colorectal cancer: a review of bacterial pathogenesis

In 2017, there were an estimated 135,430 new cases of colorectal cancer (CRC) in the United States, making if the third most common in both men and women (1). CRC was also responsible for over 50,000 deaths (1). Survival from CRC is directly related to stage of presentation, with stage I disease associated with 5-year survival of 90.1% (2). Screening lowers the incidence of CRC, shifts the detection of CRC to earlier stage disease, and lowers CRC mortality (3). Multiple societies and respective guidelines recommend CRC screening starting at age 45 to 50 with multiple modalities available. Family history and patient characteristics have been the primary means of risk stratification for CRC, and this is the basis of what age to begin, which screening methods are appropriate, and the interval with which screening is performed