For decades, blacks in the United States have had markedly greater mortality from prostate cancer compared with whites. A new study finds that the type of treatment facility utilized by patients with prostate cancer accounts for at least part of these racial disparities (Abstract 6022).
Can-Lan Sun, MD, PhD, of City of Hope, and colleagues presented a poster showing that blacks and whites experience comparable prostate-specific survival if they receive care at Comprehensive Cancer Centers (CCCs) designated by the National Cancer Institute (NCI), which are considered to be centers of excellence in research and patient treatment. For example, among patients with prostate cancer receiving care at NCI CCCs between 1998 and 2003, the 5-year survival rate was 99% for blacks and 98% for whites. However, the researchers also found that blacks with prostate cancer were less likely than whites to be treated at NCI CCCs.
The study specifically examined the underlying causes of racial differences in prostate specific survival between 53,361 whites and 11,842 blacks in Los Angeles County who were diagnosed with prostate cancer between 1976 and 2003 and followed until 2008. The study relied on data from the Los Angeles Cancer Surveillance Program, the Office of State Health and Planning Department, and three NCI CCCs serving the area — City of Hope CCC; the University of California, Los Angeles Jonsson CCC; and the University of Southern California Norris CCC.
The investigators first confirmed historical data by showing that blacks with newly diagnosed prostate cancer had a higher risk of prostate-specific mortality compared with whites in all time periods except for the most recent (i.e., 1976-1987, 1988-1997, and 1998-2003) after controlling for patient age, socioeconomic status, tumor grade and stage, treatment modality, and treatment site.
The researchers next showed that patients with prostate cancer who were treated at NCI CCCs from 1998 to 2003 had an approximately 40% lower risk of dying from their disease compared with patients treated at other medical facilities (relative risk [RR]: 0.59; p = 0.001) after adjustment for clinical and sociodemographic factors, including race. Similar results were observed for the two earlier time periods.
As mentioned, although care received at NCI CCCs yielded similar prostate-specific survival outcomes for both whites and blacks, blacks were significantly less likely to obtain care at NCI CCCs independent of socioeconomic status, insurance coverage, and tumor characteristics (p < 0.005 for all three time periods). Moreover, the gap in NCI CCC use between blacks and whites has grown larger over time, as reflected by a 1% difference from 1976 to 1987, a 5% difference from 1988 to 1997, and an 8% difference from 1998 to 2003.
Stephen B. Edge, MD, of Roswell Park Cancer Institute, who commented on this study at yesterday’s Health Services Research Poster Discussion Session, complimented Dr. Sun and colleagues on their “elegant, very detailed analysis” but pointed out the lack of explanation by the investigators as to what about the care offered in NCI CCCs improves survival outcomes — key information that could be used to improve care offered by non-NCI CCCs.
