Beyond Obesity: Metabolic Health Can Influence Cancer Risk
Two recent studies in AACR journals suggest that metabolic health problems are risk factors for some types of cancer.
“Obesity is a major under-recognized contributor to the nation’s cancer toll and is quickly overtaking tobacco as the leading preventable cause of cancer,” Ligibel et al. Journal of Clinical Oncology, 2014, 32:3568-3574.
Individuals who are overweight or obese are at increased risk for several types of cancer – colorectal cancer, endometrial cancer, gallbladder cancer, kidney cancer, pancreatic cancer, and postmenopausal breast cancers, as well as the adenocarcinoma subtype of esophageal cancer.
Moreover, for some types of cancer, being overweight or obese increases a patient’s chance of a recurrence and metastasis while decreasing the odds of survival. A major question that cancer researchers are trying to answer is: What links obesity with cancer development and adverse survival?
The answer to this question is complicated by the fact that most people who are overweight or obese have numerous other metabolic health problems, including being insulin resistant and having high blood pressure and dyslipidemia – abnormal levels of lipids such as cholesterol and triglycerides in the blood. When individuals have a combination of several metabolic health problems – including overweight/obesity, high blood pressure, high triglycerides, impaired fasting glucose, and low HDL cholesterol – at the same time, their physician may diagnose them with metabolic syndrome.
Research is beginning to reveal that the metabolic health problems often associated with being overweight or obese can themselves influence risk for certain cancers.
Two recent studies that shed light on this were published in Cancer Research and Cancer Epidemiology, Biomarkers & Prevention, journals of the American Association for Cancer Research (AACR).
In the study published in Cancer Research, researchers found that poor metabolic health increases risk for postmenopausal breast cancer irrespective of body mass index (BMI).
“Our data suggest that insulin resistance may be a significant factor in the development of breast cancer, irrespective of whether a woman is overweight or normal weight,” said the lead author of the study, Marc J. Gunter, PhD, associate professor of cancer epidemiology and prevention in the Department of Epidemiology and Biostatistics at Imperial College London’s School of Public Health.
In the second study, published in Cancer Epidemiology, Biomarkers & Prevention, researchers found that metabolic syndrome increases endometrial cancer risk independent of whether a woman is overweight or obese.
“We found that a diagnosis of metabolic syndrome was associated with higher risk of endometrial cancer, and that metabolic syndrome appeared to increase risk regardless of whether the woman was considered obese,” said the study's lead author, Britton Trabert, PhD, an investigator in the Division of Cancer Epidemiology and Genetics of the National Cancer Institute in Bethesda, Maryland.
Given that being overweight or obese is considered to be quickly overtaking tobacco as the leading preventable cause of cancer, it has been clear for some time that maintaining a healthy weight and keeping active could reduce the burden of cancer.
The evidence in these two new studies that the metabolic health problems associated with being overweight or obese can increase risk for endometrial and postmenopausal breast cancers, regardless of whether a woman is overweight or obese.
The overall message about maintaining a healthy weight remains because we know that the best way to remain metabolically healthy is to sustain a normal BMI throughout life and stay physically active, especially with regular exercise.
Read the full version of this post here, on CANCER RESEARCH Catalyst, the official blog of the American Association for Cancer Research.