Smoking tobacco modestly increases the risk of dying from prostate cancer (PCa), according to a new meta-analysis published online ahead of print in European Urology.
A team led by Farhad Islami, MD, of the American Cancer Society in Atlanta, and Stephen J. Freedland, MD, of Duke University Medical Center in Durham, N.C., analyzed 51 studies involving a total of 50,349 PCa cases, 11,823 PCa deaths, and 4.0 million cohort participants. Current cigarette smoking was associated with a significant 24% increased risk of PCa death, Dr. Freedland and colleagues reported. The risk of PCa death increased by a significant 20% with each 20 cigarettes smoked per day.
“Even if the association between smoking and PCa death is established as causal, the magnitude of association is smaller versus those reported for other smoking-related cancers including cancers of the lung and upper aerodigestive tract,” the authors wrote. “Therefore, the proportion of the PCa deaths attributed to smoking will be modest. However, because PCa is a common cause of cancer death, this association may have a considerable impact on cancer mortality at the population level.” In fact, the authors estimated that smoking contributed to more than 10,000 PCa deaths between the U.S. and Europe.
In addition, the meta-analysis showed that studies completed in 1995 or earlier—considered to be prior to the PSA screening era—found that smoking was associated with an increased incidence of PCa, whereas studies completed afterward demonstrated no or even an inverse association between smoking and PCa incidence. “This reason for this pattern is unclear,” the researchers stated. “One possible explanation is that smoking may reduce the risk of indolent nonaggressive cancers that have predominated in more recent years while promoting more aggressive cancers.”