Survival Improves in African-American RCC Patients, but Disadvantage Persists

June 30, 2016

Both African-American and Caucasian patients with advanced RCC have seen improved survival with targeted therapies, though African-Americans still experience survival disadvantages.

Both African-American (AA) and Caucasian patients with advanced renal cell carcinoma (RCC) have seen improved survival since the advent of targeted therapies, according to a new analysis. Though AA patients still have a survival disadvantage compared with Caucasians, this finding suggests that targeted therapies have benefitted both groups similarly.

Previous work had suggested that the survival disadvantage for AA patients with RCC may have been worse in the last decade compared with the 1990s, meaning that targeted therapies beginning with sorafenib in 2005 offered a differing benefit based on race.

The new study, led by Matthew I. Milowsky, MD, of the University of North Carolina Lineberger Comprehensive Cancer Center in Chapel Hill, used the National Cancer Data Base (NCDB) to assess the changes to survival in RCC patients by race over time. The results were published in Cancer.

In total, the study included 48,846 patients with RCC, 4,918 (10%) of whom were AA patients. AA patients were younger at diagnosis, less likely to be men, and had significantly lower household income; they were more likely to present with distant metastatic disease, and less likely to undergo nephrectomy.

The median overall survival (OS) in the 1998–2004 period was 6.9 months for Caucasians and 5.6 months for AA patients. These both improved significantly in the 2006–2011 period, to 8.3 months and 6.4 months, respectively (P < .01 for both). The 5-year OS rate rose from 8.4% in the earlier period to 10.3% in the 2006–2011 period in Caucasian patients; in AA patients, the rate rose from 7.5% to 8.5%.

There was no significant interaction between race and time period on survival (P = .15), suggesting that both races benefit similarly from the advent of targeted therapies. The researchers then restricted the analysis to only those patients who received systemic therapy, as access to care has been suggested as a reason for racial disparity in outcome; in that analysis, both groups had higher survival than the general population, and both Caucasian and AA patients improved over time.

Still, AA patients maintained a survival disadvantage over the course of the period studied. The unadjusted hazard ratio for death for AA patients vs Caucasian patients was 1.13 (95% CI, 1.08–1.19) in the earlier era, and 1.18 (95% CI, 1.13–1.23) in the targeted therapy era. Adjustments for a variety of factors did not dramatically change those ratios.

“Our study demonstrates that both AA and Caucasian patients with advanced RCC have had a significant increase in the rate of systemic treatment, with an accompanying improvement in survival, since the advent of targeted therapy,” the authors wrote.

The persistent survival disadvantage, though, remains concerning. “When taken together with prior studies, our study supports that differences in tumor biology other than standard histology could potentially explain these findings,” the authors wrote, adding that further study into that question is needed.