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

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

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.

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.

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.

Cancer epidemiology. 2018 Apr 28 [Epub ahead of print]

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

Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Department of Urology, SS Annunziata Hospital, "G.D'Annunzio" University of Chieti, Chieti, Italy. Electronic address: ., Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada., Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Academic Department of Urology, IRCCS Policlinico San Donato, University of Milan, Milan, Italy., Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Division of Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Vita-Salute San Raffaele University, Milan, Italy., Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Martini-Klinik Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany., Division of Urology, McMaster University, Hamilton, Ontario, Canada., Department of Urology, ASL Abruzzo 2, Chieti, Italy., Division of Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Vita-Salute San Raffaele University, Milan, Italy., Department of Urology, Medical University of Vienna, Vienna, Austria., Department of Urology, SS Annunziata Hospital, "G.D'Annunzio" University of Chieti, Chieti, Italy; Department of Urology, ASL Abruzzo 2, Chieti, Italy., Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; Department of Urology, University of Montreal Health Centre, Montreal, QC, Canada.