Obese men at higher risk for recurrence after radical prostatectomy
Obese men with prostate cancer who underwent radical prostatectomies had a greater risk for biochemical recurrence, according to a retrospective study scheduled for presentation at the American Association for Cancer Research’s special conference, Obesity and Cancer: Mechanisms Underlying Etiology and Outcomes.
“Metabolic syndrome has become quite widespread in our society, and multiple studies have shown the prevalence of obesity has drastically increased over the past decades, becoming a serious public health problem in the United States,” Arash Samiei, MD, basic scientist and clinical researcher in the department of urology at Allegheny Health Network, told HemOnc Today. “Prostate cancer is one of the most common cancers in men, and up to 30% of patients will develop recurrence after radical prostatectomy.
We believed this study and studies like this are necessary because the correlation between metabolic syndrome and different kinds of cancers still need more clarification,” Samiei added. “By preventing metabolic syndrome, we might get better oncological results after removing the prostate from patients with prostate cancer.”
As previously reported in HemOnc Today, nearly 40% of adults in the United States are considered obese — defined as a BMI of at least 30 kg/m2 — and the rate has grown steadily since 2000, according to the CDC’s National Center for Health Statistics. For men, obesity prevalence was greatest among Hispanics (43.1%), followed by whites (37.9%), blacks (36.9%) and Asians (10.1%).
Previous studies examining the link between obesity and metabolic syndrome with biochemical recurrence after radical prostatectomy have yielded mixed results.
Samiei and colleagues conducted a retrospective study of 1,100 radical prostatectomies performed by two surgeons at Allegheny General Hospital in Pittsburgh between 2003 and 2013.
Patients (median age at diagnosis, 61 years) were categorized as having low-, intermediate- or high-risk prostate cancer based on pathologic staging and grading of the disease according to National Comprehensive Cancer Network criteria.
Researchers assessed Gleason score, pathologic stage, preoperative PSA, biochemical recurrence time, surgical margin status and metabolic factors, such as fasting glucose, triglycerides, cholesterol levels, preoperative BMI and blood pressure.
Median follow-up was 44 months.
Thirty-four percent of patients were obese and 19% had metabolic syndrome according to WHO criteria.
A greater proportion of obese patients had high-risk disease than low/intermediate-risk disease (41.2% vs. 32%; P = .006).
Additionally, biochemical recurrence — defined as two consecutive postoperative PSA results higher than 0.2 ng/mL — occurred more frequently among men with BMI of 30 kg/m2 or greater than a BMI less than 30 kg/m2 (32.4% vs. 16.9%; P < .001).
Patients with metabolic syndrome also had a more than fourfold increased risk for biochemical recurrence compared with those without metabolic syndrome (OR = 4.06; P < .001).
“The apparent relationship between metabolic syndrome and prostate cancer is complex and the exact pathophysiological mechanism behind this phenomenon is not entirely known,” Samiei said.
Because this was an observational, retrospective study, future research should include large, multicenter prospective studies, Samiei said.
“More and focused research is needed to find the mechanism of cancer recurrence at the molecular level and the effect of metabolic syndrome on this process,” he said.
Samiei and colleagues also reported that obesity (P = .028) and metabolic syndrome (P < .001) correlated with higher Gleason scores, indicating more aggressive tumor cell growth following prostatectomy.
Lifestyle changes such as exercise and diets low in fats and high in proteins can prevent metabolic syndrome, while also reducing risks for type 2 diabetes, high cholesterol and high blood pressure.
“These patients need more focused follow-up care,” Samiei said. “The fact that metabolic syndrome and obesity can be treated and prevented by small changes in lifestyle and by routine follow-ups with health providers is very important. By preventing metabolic syndrome, men with prostate cancer may have a higher chance of a favorable oncological outcome following surgery.” – by Chuck Gormley
Samiei, A, et al. Abstract Poster B27. Presented at: Obesity and Cancer: Mechanisms Underlying Etiology and Outcomes; Jan. 27-30, 2018; Austin, Texas.
Disclosures: The Western Pennsylvania Prostate Cancer Foundation funded this study. Samiei and the other authors report no relevant financial disclosures.