Colorectal cancer among young people is increasing globally and rapidly. Experts predict that it will become the leading cause of death from cancer for people between the ages of 20 and 49 in the United States by 2030.
However, no one is sure why this disease suddenly strikes so many young people. In a new paper published in Sciences, Dana-Farber Cancer Institute researchers outline the complexities of the disease and the research needed to chart a course toward understanding it.
said co-author Kimmie Ng, MD, MPH, co-chair of gastrointestinal oncology and director of the Young-Honest Colorectal Cancer Center at Dana-Farber. The Center provides specialized patient care and the multidisciplinary research needed to understand colorectal cancer in young adults and develop new ways to prevent, detect and treat it.
Early onset of colorectal cancer: a unique challenge
Early-onset colorectal cancer (CRC), also called early-onset colorectal cancer, differs from later-onset colorectal cancer in several ways, according to the authors. Early onset disease is often more aggressive, presenting in the left side of the colon rather than the right, and is often accompanied by rectal bleeding and abdominal pain.
At the molecular level, studies have produced conflicting results pointing to similarities and differences in genetic mutations that lead to diseases. This is likely due to the complexity of the disease, according to the authors, and future research should take into account this variability.
Further study is also needed to determine whether CRC risk factors for young adults are similar to those for older adults. Obesity and environmental exposures, for example, have been linked to disease that starts at a young age, but other factors can play a role as well, such as increased use of antibiotics or frequent C-sections, both of which can affect the microbiome. To begin to understand risk factors, the authors suggest that investigations include a combination of genetic factors, environmental exposures, diet and lifestyle actions, as well as immune system interactions and microbiome composition.
One distinct difference is that early CRC is usually detected after the disease has progressed. This is partly due to the fact that screening for colorectal cancer begins at age 45 in the United States, so the disease often goes undetected in young adults.
“It’s important not to dismiss the idea that a young person can have colorectal cancer even though the disease is still more common in older adults,” said co-author Marios Giannakis, MD, a Dana-Farber gastrointestinal oncologist.
Respond to multidisciplinary research involving diverse populations
To account for the complexity of early CRC, Ng and Giannakis said the research needed to be multidisciplinary and encompass many areas of investigation simultaneously. For example, genome-wide association studies, which aim to find risk genes for disease, must include data about environmental exposures that can also increase risk.
These types of studies could point to new ways to identify young people who are at high risk for small-onset disease and who should be screened for CRC. “Risk classification is going to be very important when we think about screening for disease that presents at an early age,” Giannakis said.
Clinical studies should also include the collection of blood, tissue, and stool samples from patients over time to shed light on the role of immune cells, environmental exposure, and the microbiome in disease onset, progression, and treatment response. Ng and Giannakis encourage global collaborations aimed at facilitating the collection of these samples, such as the Count Me In Colorectal Cancer Project, which partners directly with patients in the United States and Canada and makes all data available for research.
Ng and Giannakis also call for more effort to ensure that diverse population groups are included in CRC inception studies. Studies show that underrepresented minorities have a disproportionate burden of CRC in young adulthood and that non-Hispanic black patients have a higher mortality rate compared to non-Hispanic whites.
The authors said: “Although each of these steps requires commitment and perseverance, it is the growing numbers of young patients who bravely combat this disease that will be the compass that keeps us on the path to better understanding, preventing and curing young adult-colorectal cancer.
