New Evidence Links Obesity to Alarming Rise of Colorectal and Gastric Cancers in Young Adults

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I was honored to orally present my study, “Rising age-specific trends of obesity-related gastrointestinal (GI) cancer correspond with increasing cancer resections in obese patients: A 2002–2013 Analysis using SEER and NIS Databases,” at the recent American College of Gastroenterology (ACG) National Scientific Meeting in Philadelphia, PA.

Image Courtesy of Hisham Hussan, MD

As the director of the obesity and bariatric endoscopy section at the Ohio State University Gastroenterology Division, my main career goal is translational and clinical research focused on the interface of energy balance, the microbiome, and gastrointestinal cancer. Furthermore, as a fellow of the NCI-sponsored Transdisciplinary Research in Energetics and Cancer Consortium, it was particularly meaningful to present this work at a time when our society is witnessing an ever-expanding population of obese individuals.

Obesity is growing in epidemiological proportions and across all age groups. For instance, there was a ten-fold increase in adolescent obesity over the past four decades. In parallel, obesity rates exceeded 37% of U.S. adults in 2014. Sufficient evidence links obesity to certain gastrointestinal cancers such as esophageal cancer, gastric cancer, pancreatic cancer, and colorectal cancer. However, little data exists on the impact of rising obesity prevalence on the incidence of these obesity-related GI cancers in certain age groups.

In our study, we proposed that the incidence of some obesity-related GI cancers is rising in certain age groups and that corresponds with increasing rates of obese patients diagnosed with these cancers. To test our hypothesis, we evaluated trends of obesity-related gastrointestinal cancers including esophageal cancer, gastric cancer, pancreatic cancer and colorectal cancer stratified by age between the years 2002 and 2013. Cancer incidence trends were obtained from the Surveillance, Epidemiology, and End Results Program (SEER) database. Obesity defined as BMI ≥ 30 kg/m2 and cancer resections rates are available in the National Inpatient Sample (NIS) database. Thus, by combining these two validated and nationally representative databases, we were able to look at cancers incidence trends and resections in relation to obesity and stratified into age groups.

Our analysis identified a significant and alarming rise in the incidence of young adults diagnosed with colorectal and gastric cancers between the years 2002–2013. This increase in young onset (less than 50 years-old) cancer incidence totaled about 15% for colorectal cancer and 7% for gastric cancer during the 11 year study period. In contrast, the colorectal and gastric cancers incidence incrementally decreased in older age groups. The incidence of pancreatic cancer increased in all age groups while that of esophageal cancer decreased during the study period.

On further evaluation of cancer resection surgeries trends, stratified by age and obesity status, we found an increase in number of patients with obesity that underwent colorectal cancer and gastric cancer resections in all age groups over time, with the steepest rise in the young adults (less than 50 years-old) age group for colorectal cancer. This trend was opposite to a temporal decrease in cancer resections in non-obese patients with colorectal and gastric cancers. Furthermore, a more pronounced increase in rates of obese patients undergoing cancer resections was seen for pancreatic and esophageal cancer. Our findings strengthen a contributing role of obesity in etiology of these cancers and are the first to tie obesity to the increasing incidence of these cancers in young adults.

Our future work will focus on the causal relationship between adolescent obesity and the rise of young-onset obesity associated GI cancers. We will also investigate the role of other factors such as sedentary lifestyle, the Western-type diet, and the microbiome, which may be to contributing to the rise in obesity associated GI cancers in young adults. Finally, we need to work on strategies including healthcare policies that tackle young-onset obesity and reduce the incidence of young onset colorectal and gastric cancers.

Dr. Hisham Hussan is a comprehensive gastroenterologist and physician-scientist with joint appointments at the Ohio State University (OSU) Wexner Medical Center and the Ohio State University Comprehensive Cancer Center. His career goal is to investigate the impact of diet, energy balance, and the microbiome on risk of developing gastrointestinal cancers.

He is the director of OSU’s GI Division, Obesity and Bariatric Endoscopy and Section (OBES). OBES works across several disciplines and provides endoscopic treatment of obesity and bariatric surgery as well as a platform for clinical trials and collaboration with scientists. He reports no conflicts of interest or financial disclosers.

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