High PCa risk seen in obese men with benign biopsy

Obese men were more likely to have precancerous lesions detected in their benign prostate biopsies compared with nonobese men and were at a greater risk for subsequently developing prostate cancer, a recently published study found.

First author Andrew Rundle, DrPH, MPH, and co-authors investigated the association between obesity and future prostate cancer incidence within a cohort of 6,692 men at the Henry Ford Health System, Detroit who were followed for 14 years after a biopsy or transurethral resection of the prostate with benign findings. The investigation was part of a larger study of environmentally induced tissue biomarkers for prostate cancer funded through a research grant awarded by the National Institutes of Health to senior co-author Benjamin Rybicki, PhD, of the Henry Ford Health System.

The authors conducted a case-control study among 494 of these patients and 494 matched controls; they found precancerous abnormalities in 11% of the patients’ benign specimens. These abnormalities were significantly associated with obesity at the time of the procedure, according to Dr. Rundle, of Columbia University Mailman School of Public Health in New York.

After accounting for several variables, including family history of prostate cancer, PSA levels during the initial procedure, and the number of PSA tests and digital rectal exams during follow-up, the authors found that obesity at the time of the initial procedure was associated with a 57% increased incidence of prostate cancer during follow-up.

Dr. Rundle noted, however, that this association was only apparent for tumors occurring earlier in the follow-up period.

“We don’t absolutely know what the true biology is,” said Dr. Rundle. “In some ways, this reflects the association between the body size and larger prostate size, which is thought to reduce the sensitivity of the needle biopsy. It is possible that the tumors missed by initial biopsy grew and were detected in a follow-up biopsy.”

The association observed between body size and prostate cancer risk is larger than that seen in prior studies, according to Dr. Rundle. He attributed the differences to the variables of the cohort, which was composed of men at high risk for prostate cancer. In addition, since these high-risk men were members of the Henry Ford Medical System, they underwent increased medical surveillance, which included repeated biopsy and regular PSA screening.

“We need some guidance on when or for whom a full follow-up is required,” Dr. Rundle said. “Obesity should be considered a factor for more intensive follow-up after a benign prostate biopsy.”

The authors publishedtheir findings online in Cancer Epidemiology, Biomarkers & Prevention (April 23, 2013).