Black patients of African descent tend to be diagnosed more frequently with prostate cancer and have higher mortality rates than patients of other races and ethnicities. Despite this substantial disparity, few prospective studies focused on maximizing the recruitment of African American patients have been conducted to address this problem. Researchers from Moffitt Cancer Center have conducted a prospective study to investigate genomic biomarkers associated with aggressive disease in African American patients with prostate cancer. Their findings were published by Awasthi et al in the Journal of the National Cancer Institute.
Many patients with prostate cancer have good outcomes during treatment and can live long, cancer-free lives; however, for some patients, including African Americans, the disease is more aggressive and leads to poorer outcomes.
Physicians typically determine how aggressive a tumor is based on an examination of tissue samples from cancer cells. Additional tests, such as bone, magnetic resonance imaging, and positron-emission tomography scans, are also performed to determine whether the cancer has metastasized. However, these examinations and tests are not optimal to identify aggressive disease because they rely on features of the tumor cells and clinical factors, not on differences in tumor genomic patterns that are associated with poorer outcomes.
Recently, scientists developed a genomic biomarker test called the Decipher score to assess the expression patterns of 22 genes associated with an increased risk of metastatic prostate cancer. Patients who have a low genomic risk of disease can be treated with less intensive therapy to limit unwanted side effects, while patients who have a high genomic risk of disease—with the possibility of poorer outcomes—can be treated with more intensive therapy to improve overall survival.
The Decipher score was developed with a patient group that was predominantly White, though additional retrospective studies that analyzed historical data found that the Decipher score was able to determine genomic risk among African American patients with similar predictive performance. Although these retrospective studies are promising, prospective studies that follow the outcomes of patients over time are more accepted.
In this study, a team of Moffitt researchers led by Kosj Yamoah, MD, PhD, Chair of Moffitt’s Radiation Oncology Department, wanted to assess whether the Decipher score was an appropriate test to use for African American patients. They partnered with two Tampa-area veterans’ hospitals—the James A. Haley Veterans’ Hospital and the Bay Pines VA Healthcare System—to enroll patients, which included 113 African American patients and 113 non–African American patients who had clinically low- or intermediate-risk prostate cancer based on clinical features. They discovered that a greater proportion of African American patients had a higher Decipher score than non–African American patients. Furthermore, patients who self-identified as African American were twice as likely to be reclassified with higher-risk disease based on results from the Decipher score than patients who self-identified as non–African American. The researchers also conducted a DNA ancestry study and confirmed that a subset of men with African ancestry were over five times as likely to undergo reclassification based on Decipher score results than non–African American men.
This research confirms that using clinical data alone is not sufficient to identify a subset of patients who are at a higher risk of poor outcomes. These approaches likely miss many patients with more aggressive prostate cancer and may result in treatment approaches that are not as effective.
“This study demonstrates the power of using genomic approaches, such as the Decipher score, to classify risk in African American [patients] and improve patient outcomes,” said Dr. Yamoah. “Our results support the integration of personalized biomarkers with conventional clinical risk classifiers, particularly for African American patients, to optimize timely detection of genomically aggressive prostate cancer and guide appropriate treatment recommendations.”
Disclosure: This study was supported by the National Cancer Institute and the George Edgecomb Society. For full disclosures of the study authors, visit academic.oup.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.