Colorectal Cancer in People with Cystic Fibrosis under the Age of 40: A Case Series

Introduction Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), a disease which affects primarily the respiratory and gastrointestinal (GI) tracts. The lifetime risk of colorectal cancer (CRC) in patients with CF is approximately 5-10 times that of the general population. In 2018, the CF Foundation CRC Screening Task Force recommended initiating CRC screening in adults with CF at age 40. Case Presentations In this case series, we present three cases of females with CF younger than age 40 diagnosed with CRC with variable presentations and stages. We discuss the data supporting current CRC screening guidelines in CF in an effort to raise awareness among clinicians regarding young-onset CRC in this population. Furthermore, we aim for this case series to help drive further investigation into the mechanisms underlying CF-related CRC and to open the door to changes in current screening practices. Conclusion People with CF are at substantially higher risk of development of CRC relative to the general population. While current CRC screening practices advocate for earlier screening in this population compared to average-risk patients, this case series highlights potential limitations to current screening guidelines.