While all men are at risk of developing prostate cancer, some men are at greater risk than others. In the United States, men of African descent are more likely to develop prostate cancer than any other race or ethnicity, and are nearly 2.2 times more likely to die from the disease. However, these statistics oversimplify the complex reality for men of African descent: across the board, African American prostate cancer patients present with higher grade disease, are younger, have higher PSA levels and have greater incidence of metastatic disease across all age groups compared with Caucasian men.
Biology or Culture?
These glaring disparities have been attributed to a multifaceted suite of cultural and biological factors. In an effort to decipher these complexities, the Prostate Cancer Foundation (PCF) launched the African American Initiative in 2013. The following year, PCF-funded researchers reported that self-identified race/ethnicity is correlated with lifestyle and ideology, which may affect healthcare seeking behavior and other environmental factors. Tied to lifestyle and related to various sociological dynamics, obesity is one such factor. Importantly, obesity appears to have a disproportionate effect on promoting prostate cancer in men of African descent, compared with Caucasian men.
Extensive research suggests that weight loss in obese men of African descent may help to normalize their disproportionate burden of aggressive disease.
The African American Initiative has also zeroed in on certain genetic aberrations, termed “biomarkers,” that are linked with elevated risk of aggressive disease. PCF researchers determined that African American men are more likely to harbor at least six known biomarkers, including overexpression of the gene SPINK1 and fusions of ERG-family genes, than men of European descent. These genetic signatures are associated with potentially lethal prostate cancers that require immediate intervention and close monitoring.
In addition, a team of PCF researchers from the Cleveland Clinic and Thomas Jefferson University discovered one of the mechanisms responsible for the treatment-resistant prostate cancer that is more common among patients of African descent. The team observed that some prostate cancers are more resistant to radiation therapy and chemotherapy than others. These radiation-resistant tumors express a small group of proteins, known as the IRDS response, which enables them to survive better during treatment.
This year, the team determined that African American patients have a much higher probability of expressing the IRDS proteins than patients of European descent. Research on IRDS proteins could fast-forward more curative treatments with radiation for men of African descent with prostate cancer. Currently, the team is working to better understand how best to analyze the IRDS response in all patients, so that they can better predict patient outcomes and, eventually, develop strategies to overcome treatment resistance.