Obesity increases a man’s risk of dying from prostate cancer, according to a massive new study by researchers in the UK, however, the causal mechanisms underpinning the link are not yet clear.
Prostate cancer is one of the most common forms of cancer to be detected in men. It is a slow-growing form of cancer, so patients can live many years after diagnosis. In fact, many patients diagnosed with prostate cancer ultimately die of other causes before the cancer develops enough to cause its own problems.
Because of the prevalence of this kind of cancer, researchers have been working to understand what factors may contribute to the development of more aggressive types of prostate cancer. Aurora Perez-Cornago, lead on the new research from the University of Oxford, said knowing the risk factors for fatal prostate cancer could help patients avoid certain damaging lifestyle practices.
“Knowing more about factors that increase the risk of prostate cancer is key to preventing it,” said Perez-Cornago. “Age, family history and black ethnicity are known risk factors but they are not modifiable, and so it is important to discover risk factors that it is possible to change.”
Excess body fat has previously been linked to higher rates of fatal prostate cancer. This new research set out to get a clearer insight on the association between body weight and prostate cancer by conducting a meta-analysis of 19 prior studies, including data from more than 2.5 million men.
The overall finding affirmed prior suspicions, with higher volumes of body weight linked to higher rates of fatal prostate cancer. Quantifying that increased risk the research found for every five point rise in body mass index (BMI), a person increased their risk of dying from prostate cancer by 10 percent.
The association between body weight and fatal prostate cancer was independent of where a person’s body weight was concentrated. But the researchers did calculate a seven percent increase in risk of dying from prostate cancer for every 10-cm (3.9-in) increase in waist circumference. Looking at UK data the study estimated around 1,300 fewer people would die from prostate cancer every year if the average BMI of men dropped by five points.
Perez-Cornago said the link between body weight and fatal prostate cancer may be clear but it still is not known what could be driving the association. It is plausible to suggest higher volumes of body fat may be driving the progression of prostate cancer. In fact, a 2018 study did hypothesize a mechanistic link between dietary fat and the metastatic progression of prostate cancer.
But the researchers also indicate other factors are likely playing a role, including differences in cancer detection between obese men and those with a healthy weight. Prostate-specific antigen (PSA) concentrations in blood samples, for example, can be lower in subjects with high BMI, meaning cancers may be detected at later stages leading to worse outcomes.
“More research is needed to determine if the association is biologically driven or due to delays in detection in men with higher adiposity,” said Perez-Cornago. “In either case, our latest results provide another reason for men to try to maintain a healthy weight.”
The new study was published in BMC Medicine.
