Chicago-Analyses of data from men in the intervention (screening) arm of the Prostate, Lung, Colorectal, and Ovary (PLCO) study show that prostatic biopsy is not associated with an increased risk of early mortality.
Rather, investigators presenting their research at the American Society of Clinical Oncology annual meeting in Chicago reported that the mortality rate at 120 days was 7.5-fold lower among men having a biopsy compared with a carefully selected control group.
Of the 38,340 men in the PLCO intervention arm, 6,834 men underwent at least one biopsy, of which about two-thirds were positive for prostate cancer. Seventeen (0.25%) of those 6,834 men died within 120 days of the biopsy, and the mortality rate was similar regardless of whether the biopsy result was positive or negative (0.30% vs. 0.16%).
In contrast, the 120-day all-cause mortality rate was 1.87% in an equally sized control group not referred to biopsy that was constructed with propensity score matching taking into account a total of 14 sociodemographic, prostate cancer-related, and medical history factors potentially influencing risk of biopsy. The 7.5-fold higher rate of death in the control group compared with the biopsy group remained after further analysis adjusting for cigarette smoking, body mass index, diabetes, age, and treatment center.
Causes of death did not differ between the biopsy group and the control group; respiratory disease and neoplasms were the leading causes of death, reported first author Mathieu Boniol, PhD, research director at International Prevention Research Institute, Lyon, France, and professor at Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, Scotland.
Selection bias may factor into findings
Reconciling these findings against the expectation that prostatic biopsy would be associated with an increased risk of mortality, the investigators postulated a role of selection bias in choosing men who do and do not undergo biopsy.
“Despite use of propensity matching to develop a comparable control group, the PLCO database contains a limited amount of information on comorbidities that clinicians would also take into account when considering prostatic biopsy,” Dr. Boniol told Urology Times. “It appears from the findings on mortality outcomes in our study that urologists are appropriately using their clinical judgment to properly select patients for biopsy who have the best chance to benefit from it and not suffer too much from potential biopsy-related complications, including death.
“However, if PSA screening becomes more widespread and the PSA threshold for performing biopsy is lowered, clinicians may not be exercising this critical medical judgment. Then, we may see a much greater burden from screening as the number of men undergoing biopsy increases.”
Discussing the study, Stephen J. Freedland, MD, agreed that the results indicate men undergoing biopsy were well selected.
Dr. Freedland“The authors also nicely say that the most likely cause of death was medical problems, and in fact, data from the PLCO show that almost two-thirds of men with prostate cancer had at least one significant comorbidity,” said Dr. Freedland, associate professor of urology and pathology at Duke University, Durham, NC.
He concluded that when discussing prostatic biopsy, men should be informed that the risks include sepsis and death. Additionally, they should be told that the risk of death is a little higher in men who are diagnosed with cancer than those who are not, which is probably explained by complications of treatment for prostate cancer or even suicide.
“However, the risk of death from the biopsy is extremely low, and the reason for performing the procedure is to find a cancer early in order to prevent a delayed death. So, there are always risks, benefits, and tradeoffs,” Dr. Freedland said.UT
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