Colorectal cancer among young people is increasing globally and rapidly. Experts expect it to become the leading cause of cancer death in individuals aged 20-49 in the U.S. by the year 2030.
Yet no one is certain why this disease is suddenly affecting so many young people. In a new paper published in Science, Dana-Farber Cancer Institute researchers outline the complexities of the disease and the research needed to map out a path toward understanding it.
Young-onset colorectal cancer (CRC), also called early-onset CRC, differs from later-onset CRC in several ways, according to the authors. Young-onset disease is often more aggressive, presents on the left side of the colon rather than the right, and often presents with rectal bleeding and abdominal pain.
At a molecular level, however, studies have shown conflicting results that suggest both similarities and differences in the genetic mutations that drive the diseases. This is likely due to the complexity of the disease, according to the authors, and future research should account for this variability.
More study is also needed to determine if CRC risk factors for young people are similar to those for older adults. Obesity and environmental exposures, for instance, have been associated with young-onset disease, but other factors could also play a role, such as increased antibiotic use or the frequency of Cesarean sections, both of which could influence the microbiome. To begin to understand the risk factors, the authors suggest that investigations should include a combination of genetics, environmental exposures, diet and lifestyle measures, as well as immune system interactions and the microbiome composition.
One clear difference is that young-onset CRC is typically discovered after the disease has advanced. This is due in part to the fact that screening for colorectal cancer starts at age 45 in the U.S., so the disease often goes undetected in younger people.
