Early-Onset Colorectal Cancer Increases Globally

Early-Onset Colorectal Cancer Increases Globally

Dr. Andrew T. Chan
The growing incidence of early-onset colorectal cancer is the topic of several presentations to be presented during the General Session, “Early-Onset Colorectal Cancer” on January 20.* Session Co-Chair Andrew T. Chan, MD, MPH, of Massachusetts General Hospital and Harvard Medical School, said that a large body of data have emerged indicating that the rate of colorectal cancer is rapidly increasing in people younger than age 50 in the United States, even as the overall rate in the population as a whole is declining.

Session speakers will highlight issues related to the epidemiology of early-onset disease, potential strategies for prevention and screening, and clinical management and survivorship concerns of younger patients.

Dr. Rodrigo Jover
Session Co-Chair Rodrigo Jover, MD, PhD, of Hospital General Universitario de Alicante, Spain, said the aim of the session “is to inform the audience about the magnitude of the problem and the possible causes, with a focus on the different realities all over the world. We also would like to give a rationale for preventing colorectal cancer among young people by adopting the more appropriate measures for that.”

A report published in August 2017 found that incidence rates in the United States have declined since the mid-1980s for colon cancer and since 1974 for rectal cancer for adults age 55 and older.1 At the same time, colon cancer rates increased by 1.0% to 2.4% annually since the mid-1980s in young adults age 20 to 39, and by 0.5% to 1.3% since the mid-1990s in adults age 40 to 54. Rectal cancer rates among adults 20 to 29 years old have increased more rapidly at 3.2% annually between 1974 and 2013. Adults born around 1990 now have double the risk of colon cancer and quadruple the risk of rectal cancer compared with adults born around 1950.1

“These statistics are alarming because the reasons for these trends are unclear,” Dr. Chan said. The trend may eventually be a global concern. “In general, colorectal cancer is becoming a disease that is seen more commonly in other parts of the world. In the future, other parts of the world may begin seeing a larger number of cases at younger ages,” he said.

Dr. Jover said that the annual incidence of colorectal cancer is expected to increase in less developed regions of the world over the next 2 decades in all age groups. Although data are lacking about early-onset disease in many parts of the world, data from Egypt, Turkey, and Iran “are showing a similar trend of increasing incidence of colorectal cancer in people younger than age 50,” Dr. Jover said.

The first speaker in the session will be Joseph J.Y. Sung, PhD, MBBS, of the Chinese University of Hong Kong, who will discuss the epidemiology of early-onset colon cancer in the United States and around the world.

Dr. Chan noted that lifestyle, environmental exposures, and obesity may contribute to the increasing rates of colorectal cancer among young adults. “But that’s not the complete explanation. There are clearly other patterns in the incidence figures that suggest the increase in early-onset colorectal cancer is not due solely to increased obesity rates,” he said. 

Other explanations could be changes in dietary habits and exposure to pollutants and antibiotics, which may be associated with changes in the gut microbiome that has been implicated in colorectal cancer.

Societies around the world that are adopting lifestyle habits more commonly associated with high-income countries like the United States are also experiencing increasing rates of colorectal cancer, Dr. Chan said.

“As we start seeing changes in the United States, we can expect that these changes may also follow in populations around the world after some time lag,” Dr. Chan said. “We need to consider that lifestyle and environmental exposures, not just genetics, seem to play a role in the development of cancer. These issues will become very important to consider when we strategize about how to handle the global burden of colorectal cancer.”

Fay Kastrinos, MD, MPH, of the Columbia University Medical Center, will discuss health disparities and screening and prevention issues related to early-onset colorectal cancer. As community oncologists and internists encounter more young adults with colorectal cancer, questions are being raised about prevention strategies for this population, including possible changes to screening guidelines. Population-based screening for adults over age 50 has led to a decrease in colorectal cancer rates, but this type of screening is not yet recommended for younger age groups.

“We may need to at least begin to have the conversation about beginning screening at earlier ages if these trends continue,” Dr. Chan said. As more is understood about the risk among certain subsets of the younger population, strategies for targeted screening for those at higher risk could be considered, he said.

The presentation by Irit Ben-Aharon, MD, PhD, of the Davidoff Cancer Center, Israel, will highlight the special needs of this patient population, their clinical management, and survivorship issues. Young women, for example, will have concerns about fertility preservation, and family members of patients will be concerned about their own risk.

“We will also consider how genetic predisposition plays a role in early-onset colorectal cancer and the potential implications for counseling patients and their families,” Dr. Chan said. “There is growing concern in the clinical community about these trends. Many of us are seeing younger patients with colorectal cancer in our clinics. Trying to understand the reasons behind these trends is critical to how we think about prevention and treatment.” 

−Kathy Holliman, MEd

*Program information as of November 6, 2017. For session time and location information, please refer to the iPlanner.