Racial disparities: An unexplained factor in kidney cancer survival
A grimmer prognosis awaits African-Americans when compared to Caucasian patients suffering from renal cell carcinoma (RCC), the most common form of invasive kidney cancer.
In a recent study lead at the National Cancer Institute and published in the Cancer journal, researchers found that African-Americans tend to have a poorer 5-year survival rate than Caucasians regardless of clinical data and patient demographics. "There is a consistent disparity between the races," said Wong-Ho Chow, Ph.D., professor in MD Anderson's Department of Epidemiology and lead investigator on the study.
In this study, clinical data and demographics of nearly 40,000 RCC patients diagnosed over a 15-year period from 12 registries in the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program, were analyzed.
The study revealed the 5-year relative survival rate for Caucasians diagnosed with invasive kidney cancer was 72.6% as compared to 68% for African-Americans regardless of age, sex, tumor size or stage, type of RCC and surgical procedures performed. SEER data also showed a poorer survival rate among men and older patients as compared to women and younger patients.
Although research has shown an increase in risk of renal cell carcinoma when linked to hypertension, which disproportionately affects African- Americans, Chow notes that the study did not have appropriate data to investigate if high blood pressure may have contributed to the racial disparity in survival after cancer diagnosis.
The findings suggest that African-Americans not only have higher incidence rates of RCC, but also lower survival rates after RCC diagnosis.
RCC, the most common type of kidney cancer in adults and the most deadly cancer among urological tumors, affects more than 30,000 men and women every year in the United States.
Although African-Americans tend to be diagnosed with papillary RCC, which is a subtype of kidney cancer associated with a better survival rate as compared to clear cell RCC - a subtype of RCC more commonly diagnosed in Caucasians - they were still at a disadvantage when it comes to survival.
The study also revealed that Caucasians have a survival advantage over African-Americans in all categories except for the patients who didn't have surgical removal of the kidney. In fact, both racial groups had an equally poor prognosis of survival and were worse off than patients who had surgical procedures.
Chow noted that differences in access to health care and delayed tumor diagnosis do not appear to be the reason for the disparities as African-Americans were more likely to be diagnosed at the localized stage, and disadvantages for this racial group occurred across all tumor sizes and stages.
"A clear explanation for the disparity is not known. More research is needed to investigate reasons for the racial disparity in renal cell cancer survival," Chow noted. "We should note that survival is best in all patients when the cancer is caught early when it can be effectively removed by surgery."
Racial disparity in renal cell carcinoma patient survival according to demographic and clinical characteristics