Effect of African-American race on cancer specific mortality differs according to clear cell vs. non-clear cell histologic subtype in metastatic renal cell carcinoma

Publication date: June 2018

Source: Cancer Epidemiology, Volume 54

Author(s): Michele Marchioni, Sabrina S. Harmouch, Sebastiano Nazzani, Marco Bandini, Felix Preisser, Zhe Tian, Anil Kapoor, Luca Cindolo, Alberto Briganti, Shahrokh F. Shariat, Luigi Schips, Pierre I. Karakiewicz

Abstract

Aim

To test the effect of African-American race on cancer specific mortality (CSM) in clear cell metastatic renal cell carcinoma (ccmRCC) and non-ccmRCC.

Patients and methods

Within Surveillance, Epidemiology and End Results registry (2001–2014), we identified patients with ccmRCC and non-ccmRCC. We relied on propensity score (PS) matching to reduce the effect of inherent differences between African-American vs. Caucasian patients. After PS matching that included access to cytoreductive nephrectomy (CNT), cumulative incidence, competing-risks regression (CRR) models and landmark analyses tested the effect of race on CSM.

Results

Before PS matching, African-American patients accounted for 7.0 and 24.5% of respectively ccmRCC (N = 6742) and non-ccmRCC patients (N = 766). After PS matching, African-American patients accounted for 22.3 and 33.5% of respectively ccmRCC (N = 2050) and non-ccmRCC (N = 391) matched cohorts. In multivariable CRR models focusing on ccmRCC, higher CSM was recorded in African-Americans (HR:1.27, p < 0.001). Conversely, in non-ccmRCC, lower CSM was recorded in African-Americans (HR:0.54, p < 0.001). Landmark analyses rejected the hypothesis of immortal time bias.

Conclusion

African-Americans experienced higher CSM in ccmRCC. Conversely, African-Americans experienced lower CSM, when diagnosed with non-ccmRCC. These differences are independent of access to CNT and warrant further study since they may have an impact on efficacy or access to systemic therapies.

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