Geographic Distribution of Racial Differences in Prostate Cancer Mortality.

Importance: While racial disparities in prostate cancer mortality are well documented, it is not well known how these disparities vary geographically within the US. Objective: To characterize geographic variation in prostate cancer-specific mortality differences between black and white men. Design, Setting, and Participants: This cohort study included data from 17 geographic registries within the Surveillance, Epidemiology, and End Results (SEER) database from January 1, 2007, to December 31, 2014. Inclusion criteria were men 18 years and older with biopsy-confirmed prostate cancer. Men missing data on key variables (ie, cancer stage, Gleason grade group, prostate-specific antigen level, and survival follow-up data) were excluded. Analysis was performed from September 5 to December 25, 2018. Exposure: Patient SEER-designated race (ie, black, white, or other). Main Outcomes and Measures: Fine and Gray competing-risks regression analyses were used to evaluate the difference in prostate-cancer specific mortality between black and white men. A stratified analysis by Gleason grade group was performed stratified as grade group 1 and grade groups 2 through 5. Results: The final cohort consisted of 229 771 men, including 178 204 white men (77.6%), 35 006 black men (15.2%), and 16 561 men of other or unknown race (7.2%). Mean (SD) age at diagnosis was 64.9 (8.8) years. There were 4773 prostate cancer deaths among white men and 1250 prostate cancer deaths among black men. Compared with white men, black men had a higher risk of mortality overall (adjusted hazard ratio [AHR], 1.39 [95% CI, 1.30-1.48]). In the stratified analysis, there were 4 registries in which black men had worse prostate cancer-specific survival in both Gleason grade group 1 (Atlanta, Georgia: AHR, 5.49 [95% CI, 2.03-14.87]; Greater Georgia: AHR, 1.88 [95% CI, 1.10-3.22]; Louisiana: AHR, 1.80 [95% CI, 1.06-3.07]; New Jersey: AHR, 2.60 [95% CI, 1.53-4.40]) and Gleason grade groups 2 through 5 (Atlanta: AHR, 1.88 [95% CI, 1.46-2.45]; Greater Georgia: AHR, 1.29 [95% CI, 1.07-1.56]; Louisiana: AHR, 1.28 [95% CI, 1.07-1.54]; New Jersey: AHR, 1.52 [95% CI, 1.24-1.87]), although the magnitude of survival difference was lower than for Gleason grade group 1 in each of these registries. The greatest race-based survival difference for men with Gleason grade group 1 disease was in the Atlanta registry. Conclusions and Relevance: These findings suggest that population-level differences in prostate cancer survival among black and white men were associated with a small set of geographic areas and with low-risk prostate cancer. Targeted interventions in these areas may help to mitigate prostate cancer care disparities at the national level.