Environmental exposures may drive prostate cancer risk
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Prostate cancer is the most common form of cancer among men in the United States outside of skin cancers, and researchers from the UIC School of Public Health and College of Medicine have published a new study highlighting the likelihood of environmental exposures in driving high-risk prostate cancer cases.
In 2019, nearly 175,000 newly diagnosed cases and more than 31,500 deaths occurred in the U.S. About 90 percent of cases are not considered life-threatening. Among the high-risk cases, researchers identified a positive association between worsening environmental quality and odds of metastatic prostate cancer at diagnosis.
“Our findings suggest that environmental factors can drive risk for more aggressive prostate cancer, but more work is needed to determine specifically which modifiable factors are the strongest predictors,” said Jyotsna Jagai, PhD, research assistant professor of environmental and occupational health sciences and a co-author of the study.
The study, published in the journal Prostate Cancer and Prostatic Diseases, examined more than 250,000 cases from 611 counties across the country, of which about eight percent of cases were metastatic at diagnosis. Environmental exposures were measured using the Environmental Quality Index (EQI) developed by the U.S. Environmental Protection Agency, a source of summarized environmental data at the county level. The EQI provides exposure levels across five domains:
- Air: measuring pollutants such as carbon tetrachloride, diesel engine emissions, polychlorinated biphenyls and vinyl chloride
- Land: including measures of pesticides, land-based contaminants such as lead, arsenic, iron, and phosphorus
- Built domain: road and highway quality, public transportation, business and dietary environment
- Water: water quality, drought, calcium deposition, mercury deposition, and water contamination with alpha particles, selenium, and other chemical contaminations
- Sociodemographic: residential vacancy, median household value, median household income, persons earning high school education, persons below the poverty level, unemployment rate, and median number of violent crimes per capita
Researchers found the strongest associations among the land, water and sociodemographic domains. Understanding of the effects of land and water exposures is still developing. It is widely thought that environmental endocrine disruptors can alter the cellular hormonal homeostatis and promote prostate carcinogensis.
In the land domain, for example, the insecticide chlordecone is a known endocrine disruptor and has been shown to have a significant impact on aggressive prostate cancer cases. Among water exposures, single-agent pollutants such as perfluorinated acids found in industrial surfactants and nitrates found in fertilizers have been associated with prostate cancer mortality.
Previous studies have implicated the role of sociodemographic characteristics in prostate cancer outcomes, with men from low socioeconomic classes less likely to be screened, more likely to have advanced disease at diagnosis and less likely to undergo radical prostatectomy, or surgical removal of all or part of the prostate gland. Diving deeper, self-identified Black men had a stronger relationship with overall EQI to metastatic prostate cancer at diagnosis as compared to self-identified White men.
”The sociodemographic domain is likely acting as a proxy for several factors that have been shown to be associated with aggressive prostate cancer, including access to care,” Jagai said. “This association was not particularly surprising.”
The study was limited in that it provides a broad look at the county level and does not take into account individual exposures. Jagai says more specific exposure studies will foster better understanding of the impact of environmental exposures that could be modified.
Hari T. Vigneswaran, MD, resident of urology at the UIC College of Medicine, is the study’s lead author. Other co-authors from the UIC College of Medicine include David T. Greenwald, MD, former resident of urology; Megh Kumar, urology student; Ryan W. Dobbs, MD, resident of urology; Daniel Moreira, MD, assistant professor of urology; and Michael R. Abern, MD, director of urologic oncology and associate professor. Achal P. Patel is also a co-author.