Among patients with the most common form of kidney cancer, whites consistently have a survival advantage over blacks, regardless of patient and tumor characteristics or surgical treatment. That is the conclusion of a new study published early online in Cancer, a peer-reviewed journal of the American Cancer Society. The study's results suggest that additional efforts are needed to prolong the survival of all patients with kidney cancer.

Since the mid-1990s, black Americans have had a higher incidence of renal cell carcinoma, the most common form of kidney cancer, than white Americans. Research also suggests that there are racial disparities in the survival of patients with renal cell carcinoma, with black patients dying earlier than whites.

When Wong-Ho Chow, PhD, currently of The University of Texas MD Anderson Cancer Center in Houston, and her colleagues at the National Cancer Institute analyzed national data of nearly 40,000 renal cell carcinoma patients, they confirmed the poorer survival rates for black patients compared with whites. Specifically, 72.6 percent of white patients survived for at least five years, compared with 68.0 percent of black patients. The survival advantage of white patients over black patients was consistently seen in all subgroups of patients, regardless of gender, age, tumor stage or size, tumor subtype, or type of surgical treatment.

Surprisingly, a higher percentage of black patients than white patients were diagnosed at the localized stage, with smaller tumors, or with a less aggressive subtype of cancer. These factors should indicate a better prognosis. Also, compared with white patients, a slightly higher percentage of black patients received no surgical treatment, which is associated with a substantially poorer prognosis.

Additional studies are needed to determine why these disparities exist. "We cannot rule out the possibility that other factors not measured in our study -- such as obesity, high blood pressure, access to care, and genetic susceptibility -- may be contributing to the persistent disparities," said Dr. Chow.