ASCO Reading Room | Dr. Mitch Hayes discusses the adoption of new therapies for metastatic renal cell carcinoma

Many new therapies have been approved in the past decade for patients with metastatic clear cell renal cell carcinoma (mRCC), but have access to these new therapies and survival outcomes been equitable by race? Research presented at the ASCO Genitourinary Cancers Symposium explored this question.

Dr. Mitch Hayes and colleagues at the H. Lee Moffitt Cancer Center & Research Institute in Tampa, Florida, analyzed data from 7,133 patients in the Flatiron Health longitudinal database treated from 2011 to 2022. The majority (69%) were white, while 7% were Black and about 13% were “other nonwhite.”

Overall, 31.4% of patients received at least one recently approved therapy during the study period, and access to therapies did not differ significantly by race (31.8% for whites, 31.5% for blacks, and 30.5% for other races).

However, black race was associated with a 24% higher risk of mortality compared with white race (95% CI 1.11-1.39, P= 0.0003). The risk was more pronounced in patients younger than 65 years (95% CI 1.17-1.63, P=0.0001).

“This study assessed real-world access to new therapies as well as racial and social disparities in patients with mccRCC and their impact on clinical outcomes,” the researchers wrote. “This is the first study in the immunotherapy era to highlight poorer overall survival in black patients with mccRCC.”

Hayes provided additional details and discussed the implications in the following interview.

Tell us more about the Flatiron database and how it captures real-world data.

Hayes: Flatiron Health collects longitudinal clinical data from community and academic medical oncology practices nationwide through a proprietary electronic medical record system. Granular variables relevant to oncology are then extracted and organized, giving researchers access to standard variables you might find in the cancer registry, but also many other unique data points, such as monthly details on specific prescriptions and lab information. This is the foundation of our project, which examined racial disparities in the use of new therapies for mccRCC. Flatiron data can tell us exactly what prescriptions patients received, when, and for how long.

Were you surprised by the finding that access to new therapies did not differ by race?

Hayes:We hypothesized that new therapies would indeed differ by race, but we found, after univariate analysis, that adoption did not differ by race. However, I don’t think we can conclude at this point that race does not impact the use of new therapies. We know that these groups have baseline differences in factors that might affect the use of a new therapy, as well as in unmeasured factors.

We thus hope to continue this work using a contemporary multivariate mediation approach for additional answers.

If access to new therapies were equal, what might explain racial disparities in survival outcomes?

Hayes: I think that if we find, after adjusting for several factors, that the use of new therapies has no impact on survival disparities, then the remaining causes can be reduced to a manifestation of racism or, much less likely, a biological cause.

“Race” is a social construct, and self-identified racialized groups are not a reliable indicator of genetic predisposition to worse clinical outcomes. These are vastly different questions, but I am hopeful that further research can elucidate the answers.

Did your study reveal other patient characteristics associated with survival outcomes or access to new therapies?

Hayes: Yes, it is interesting that the univariate analysis found that younger patients and patients treated in a community practice were more likely to be treated with a new first-line therapy. I think the younger patient effect makes sense, as perhaps younger patients (and their oncologists) are more motivated to be treated with the “latest thing,” or perhaps the reverse is that ageism plays a role for older patients.

The effect of practice setting is puzzling, and we are not entirely sure why this is so. The patient populations in academic and community practices who are prescribed first-line therapy are distinct. Again, multivariate analysis would be needed to determine whether this is more related to the patient than the provider.

Do you plan further research in this area?

Hayes: Yes, we are currently preparing to share the results of a multivariate mediation analysis that will further examine the impact of adoption of new therapies on the survival disparity we see in mccRCC.

Another observation from this study is the still very low number of patients receiving second-line therapy (approximately 66% of patients receiving at least one systemic therapy for mccRCC). This figure is consistent with historical data; however, further research is needed to determine the possible causes of this phenomenon and whether this rate is changing over time.

Read the study here and expert commentary on it here.