Study finds more precise fat measurements may improve colorectal cancer risk prediction

A study led by researchers at the University of Arizona Comprehensive Cancer Center emphasizes the need for improved and standardized methods to measure body fat when assessing colorectal cancer risk. The work, published in Obesity, is the first systematic review to focus on advanced body composition techniques—beyond traditional metrics like body mass index—and their associations with colorectal cancer incidence. 

The project was supervised by Jennifer Bea, PhD, a member of the U of A Cancer Center and associate professor in the Mel and Enid Zuckerman College of Public Health. Doctoral student Shelby G. Ziller, one of Bea’s mentees, is the paper’s first author. 

“Body mass index has long been used as a convenient measure of obesity-related cancer risk, but it cannot distinguish between fat and lean tissue or indicate fat distribution,” Bea said. “This study highlights how more precise tools—such as DEXA scans and CT imaging—can deepen our understanding of how fat distribution impacts cancer risk.” 

After analyzing more than 7,000 studies and narrowing the final review to 15 high-quality articles, the team found consistent patterns suggesting that specific fat-related metrics—such as total body fat percentage, fat mass, and visceral adipose tissue—are positively associated with colorectal cancer risk, especially in men.  

While body mass index is a simple ratio of weight to height, total body fat is a measurement of the actual percentage of body weight that is fat, and fat mass indicates the total weight of fat in a person’s body. Fat stored around abdominal organs is called visceral adipose tissue. 
 
Two large studies found statistically significant increased risk—between 9% and 59%—related to higher total body fat percent and fat mass. In contrast, rectal cancer showed weaker or nonsignificant associations. 

Visceral adipose tissue was significantly associated with increased colorectal cancer risk in some studies, especially those using high-precision CT scans. Subcutaneous fat, which is located directly beneath the skin, showed more variable associations, and in some cases, even appeared protective. Still, inconsistencies across study designs, fat measurement tools, and regions of interest prevented firm clinical recommendations. 

The review underscores the urgent need for standardized fat measurement methods in both research and clinical practice to enable reliable comparisons across studies and patient populations. 

“This work is a call to action for the field,” Bea said. “If we can more accurately assess body composition, we’ll be better equipped to identify who is at increased risk—and ultimately improve prevention efforts.” 

The study also points to disparities in the availability of advanced body composition data, which is more common in countries with mandatory health screenings or military service. The authors recommend larger, more diverse cohort studies using standardized protocols to improve our understanding of how fat distribution impacts cancer risk in different populations.