To do so, they performed a retrospective cohort study using VA Informatics and Computing Infrastructure (VINCI) and SEER. They identified all patients diagnosed with bladder cancer between 2000 and 2018 with American Joint Committee on Cancer (AJCC) stage 0-4 disease. The authors assessed outcomes including overall survival (OS), bladder cancer-specific survival (BCS), and non-bladder cancer-specific survival (NCS) using multivariable Cox and Fine-Gray models.
In both cohorts, Black patients were younger at diagnosis and were more likely to have non-urothelial histology. Further, Black patients were more likely to have muscle-invasive bladder cancer, to have node-positive disease, and to have metastatic disease at the time of presentation. While there were differences in both health care models, Dr. Kotha noted that the magnitude of the discrepancy in stage at presentation was much larger in the SEER cohort (~10% difference in MIBC between white and black patients) and compared to the VHA cohort (~4% difference in MIBC between white and black patients).
In the VA cohort, the authors identified 36322 veterans (9.0% black, 91.0% white) who were diagnosed with bladder cancer. Compared to their white contemporaries, black veterans were more likely to have more comorbidities reside in zip codes with lower median income and education levels and present with higher stage disease (AJCC stages 2-4) (23.3% vs 19%).
Interestingly, examining unadjusted curve, the authors found significantly worse overall and bladder cancer-specific mortality for Black patients in the SEER cohort though this difference was not notable in the VHA cohort.
Following multivariable adjustment for disease stage among other covariables, the authors found no statistically significant differences on the basis of patient race in any survival endpoint among patients treated in the VHA system. In contrast, using the SEER dataset, the authors identified statistically significant inferior outcomes in all survival endpoints for black patients compared to white patients, among 130,998 patients (5.9% black, 94.1% white) with bladder cancer.
Thus, the authors conclude that an equal access health care system eliminates observed differences in survival between black and white patients with bladder cancer and underscore the need to bridge healthcare disparities across racial groups.
Presented by: Nikhil V. Kotha, MD, Department of Surgery, University of California
Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Contact: @WallisCJD on Twitter during the 2021 American Society of Clinical Oncology Genitourinary Cancers Symposium (#GU21), February 11th-February 13th, 2021