Studies Find That Blood and Body Fats Drive Prostate Cancer

Emma Allott, PhD

Fats in blood and on the body increase men’s prostate cancer risk, two studies have found.

Cholesterol, Triglycerides Trigger PC Recurrence

In a study published in Cancer Epidemiology, Biomarkers & Prevention, researchers found that higher levels of total cholesterol and triglycerides in the blood of men who underwent radical prostatectomy for prostate cancer were associated with an increased risk of biochemical disease recurrence.

“While laboratory studies support an important role for cholesterol in prostate cancer, population-based evidence linking cholesterol and prostate cancer is mixed,” Emma Allott, PhD, postdoctoral associate at the Duke University School of Medicine in Durham, North Carolina, stated in a press release issued by the American Association for Cancer Research. “Understanding associations between obesity, cholesterol, and prostate cancer is important given that cholesterol levels are readily modifiable with diet and/or statin use, and could therefore have important, practical implications for prostate cancer prevention and treatment.”

Allott worked with Stephen Freedland, MD, associate professor of Surgery at Duke University School of Medicine, and colleagues on the study.

The team analyzed data from 843 men who were diagnosed with prostate cancer and then underwent radical prostatectomy without ever taking statins first. Compared with patients whose triglyceride levels were normal, they found, men with serum triglyceride levels of 150 mg/dL or higher faced a 35% higher risk of biochemical prostate cancer recurrence. Among men with abnormal blood lipid profiles, every 10 mg/ dL increase in total serum cholesterol above 200 mg/dL added a 9% increase in the risk of biochemical prostate cancer recurrence, and every 10 mg/dL increase in triglycerides above the abnormal cut point of 150 mg/dL was associated with a 3% increased risk of biochemical recurrence, according to the study. Meanwhile, men with lower levels of “good cholesterol,” or high density lipoprotein (HDL), reduced their chances of recurrence when they increased their levels of the protein. In men whose baseline levels were below the desirable value of 40 mg/dL, every 10 mg/dL increase in HDL lowered the risk of prostate cancer recurrence by 39%.

Study subjects were identified from the Shared Equal Access Regional Cancer Hospital (SEARCH) database and treated at one of the six Veterans Affairs Medical Centers in California, North Carolina, and Georgia.

Obesity Tied to Deadliest Prostate Cancers

A separate, ongoing systematic review of global research has demonstrated that men who are overweight or obese face an increased risk of the deadliest forms of prostate cancer, its authors have reported.

The report by an independent expert panel collectively analyzed 104 studies involving more than 9.8 million men and more than 191,000 cases of prostate cancer, according to a press release issued by one of the organizations that wrote it, the American Institute for Cancer Research (AICR). Titled Diet, Nutrition, Physical Activity and Prostate Cancer, the study was conducted in partnership with the World Cancer Research Fund (WCRF) International’s Continuous Update Project (CUP).

Based on these findings, the AICR now estimates that 11% of all advanced prostate cancer cases in the United States could be prevented through the maintenance of healthy body weight, according to the press release.

The findings make prostate cancer the ninth cancer linked to obesity by experts from AICR and WCRF International. In previous reports, the groups found that excess body fat increases the risk of ovarian cancer, post-menopausal breast cancer, colorectal cancer, endometrial cancer, esophageal cancer, kidney cancer, gallbladder cancer, and pancreatic cancer.

This is the first time our rigorous process has uncovered a clear and consistent link between body fat and prostate cancer,” said CUP Panel lead Edward Giovannucci, MD, ScD, of the Harvard School of Public Health, in the press release. “Today we have something new to tell men worried about this disease: You can take steps to help protect yourself from its most aggressive and deadliest forms.”

Giovanucci added that, while many thousands of prostate cancers will never become life-threatening, “it’s become clear that obesity is linked to those aggressive, often deadly forms, and not to the latent or indolent forms.”

Meanwhile, the report downgrades the strength of previous evidence that suggested that lycopene and selenium could reduce men’s risk for prostate cancer. Another previous finding, that diets high in calcium were associated with increased prostate cancer risk, has been downgraded to “limited, but suggestive” by the groups, according to the release.

References

Allott EH, Howard LE, Cooperberg MR, et al. Serum lipid profile and risk of prostate cancer recurrence: results from the SEARCH database. Cancer Epidemiol Biomarkers Prev. 2014;23(11):2349-2356.