New research crunches the numbers on diabetes- and obesity-related cancers and projects a steep rise in diagnosed cases.
Researchers at several institutions worldwide — including Imperial College London in the United Kingdom and the International Agency for Research on Cancer of the World Health Organization (WHO) in Lyon, France — have recently established that cancers related to metabolic diseases, especially diabetes and obesity, have an increasingly high incidence.
According to the team's data, 5.6 percent of all cancer cases throughout the world in 2012 were linked to pre-existing diabetes and a high body mass index (BMI), which is defined as over 25 kilograms per square meter.
Of this total, 3.9 percent of cases were attributable to diabetes — almost twice as many cases as were related to a high BMI.
Lead study author Dr. Jonathan Pearson-Stuttard and colleagues also worked out the estimates for the probable incidence of cancers related to diabetes and other metabolic disease in the next few years, and their prognosis is not encouraging.
Diabetes, high BMI increasingly dangerous
These numbers are particularly concerning, since diabetes and obesity are established risk factors for many different types of cancer, such as colorectal and pancreatic cancer, as well as cancer of the liver and gallbladder, breast cancer, and endometrial cancer.
The more prevalent these metabolic conditions, the more concerned specialists become that the risk of cancers related to them may also increase.
"As the prevalence of these cancer risk factors increases, clinical and public health efforts should focus on identifying preventive and screening measures for populations and for individual patients."
Dr. Jonathan Pearson-Stuttard
"It is important that effective food policies are implemented to tackle the rising prevalence of diabetes, high BMI, and the diseases related to these risk factors," he adds.
The new study took into account the increase in the incidence of 18 types of cancer related to diabetes and high BMI in 175 countries between 1980 and 2002.
Using data provided by GLOBOCAN, the researchers studied the incidence of 12 types of cancer across 175 countries in 2012, taking into account patient age and sex.
Dr. Pearson-Stuttard and colleagues noticed that the majority of cancer cases that were related to diabetes and a high BMI — that is, 38.2 percent of cases — could be pinpointed to high-income Western countries. The second highest occurrence was noted in east and southeast Asian countries, accounting for 24.1 percent of cases.
Low- and middle-income countries have fewer cases of cancer overall, but diabetes and a high BMI seemed to have a stronger impact in these regions. In countries such as Mongolia, Egypt, Kuwait, and Vanuatu, between 9 and 14 percent of all cancers were related to BMI and diabetes.
At the same time, however, Tanzania, Mozambique, and Madagascar had the lowest incidence of diabetes- and weight-related cancers, pointing to stark geographical contrasts in terms of epidemiology.
On a global level, the most common types of cancer from the ones targeted in this study were cancer of the liver (24.5 percent of cases) and endometrial cancer (38.4 percent of cases).
In a region-specific context, 30.7 percent of cases were caused by liver cancer in high-income Asia Pacific. Liver cancer also accounted for 53.8 percent of cases in east and southeast Asian countries.
In high-income Western countries, as well as in central and eastern Europe and sub-Saharan Africa, breast cancer and endometrial cancer were responsible for 40.9 percent of cases.
Worrying forecast for cancer rates
The researchers explain that an increase in diabetes diagnoses between 1980 and 2002 caused a 26.1 percent increase in related cancers in 2012. Likewise, more widespread obesity was responsible for a 31.9 percent increase in BMI-related cancers between 1980 and 2002.
More worryingly, Dr. Pearson-Stuttard and colleagues estimate that the number of cancer cases related to diabetes and obesity are set to rise worldwide as these metabolic conditions become more widespread.
A projected increase in diabetes- and weight-related cancers in 2025 indicates a more than 30 percent rise in cancer diagnoses for women and an over 20 percent rise on average for men.
According to Dr. Pearson-Stuttard, "Increases in diabetes and high BMI worldwide could lead to a substantial increase in the proportion of cancers attributable to these risk factors, if nothing is done to reduce them."
"These projections are particularly alarming," he adds, "when considering the high and increasing cost of cancer and metabolic diseases, and highlight the need to improve control measures, and increase awareness of the link between cancer, diabetes, and high BMI."
The best solution at this point, the researchers urge, is to make a sustained effort to prevent the rise of metabolic diseases, in order to reduce the future risk of cancer.