Prostate Cancer Risk Associated with Metabolic Factors
NIAGARA FALLS, Ont.—New research findings suggest that having more components of the metabolic syndrome is associated with a higher risk for developing any prostate cancer (PCa).
In a study, Bimal Bhindi, MD, and colleagues at the University of Toronto found that men with three or more components of the metabolic syndrome had 38% higher odds of being diagnosed with PCa than men with no risk factors, and they had 52% and 43% higher odds of being diagnosed with clinically significant PCa (cancers fulfilling grade and/or volume criteria making the cancer less suitable for surveillance) or high-grade PCa (Gleason 7 or higher), respectively.
“In our study, the individual components of metabolic syndrome were not associated with prostate cancer, but increasing number of metabolic risk factors were,” said Dr. Bhindi, a urologic surgery resident, who presented the findings at the Canadian Urological Association's 2013 annual meeting. “In the cardiovascular literature, many argue whether metabolic syndrome is greater than the sum of its parts. In our study, at least for its relationship with PCa, it does appear to be greater than the sum of its parts.”
Dr. Bhindi's group evaluated the association between five components of the metabolic syndrome and PCa in men whose biopsy samples are included in the GenitoUrinary BioBank at the Princess Margaret Hospital in Toronto. These components included elevated fasting glucose concentration or diabetes, obesity, elevated levels of triglycerides, low concentration of high-density-lipoprotein cholesterol, and hypertension.
“Obesity is associated with a hemodilution of PSA, therefore decreasing the risk of referral for biopsy,” he said. “In our study, everyone had a biopsy, therefore circumventing this potential source of bias,” he said. All of the 2,144 patients who were included in the analysis underwent a biopsy for suspected cancer. None were on active surveillance. The biopsies revealed that 1,301 (60.7%) men had PCa. Of these, 593 (45.6%) had a Gleason score of at least 7.
“Researchers are generally conservative in concluding that there is a causal relationship,” Dr. Bhindi said. “Our analysis is cross-sectional and cannot alone establish cause and effect. Although still slightly premature, the case for a causal relationship is strengthened by our study, particularly in that we demonstrated a biological gradient.”