Effect of race and socioeconomic status on surgical margins and biochemical outcomes in an equal-access health care setting: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

BACKGROUND: The impact of race and socioeconomic status (SES) in prostate cancer (CaP) outcomes has been well-studied, but controversy remains. The associations of race/SES with intermediate CaP outcomes, including positive surgical margin (PSM) and biochemical recurrence (BCR), were explored in an equal-access setting.
METHODS: Data were retrospectively collected from 2502 men in the Shared Equal Access Regional Cancer Hospitals (SEARCH) database who underwent radical prostatectomy from 1989 to 2010. SES (income, education, employment, and poverty) was estimated from linkage of home ZIP code to census data. Logistic regression with adjustment for pre- and postoperative covariates estimated risk for associations between race/SES and pathologic outcomes. Cox proportional hazards models estimated risk for associations between race/SES and time to BCR.
RESULTS: Black men were more likely to have lower SES than white men (P < .001). On multivariate analysis, race was not associated with PSM, but higher SES was associated with less PSM and fewer Gleason sum ≥ 7 pathologic tumors when SES was assessed by education, employment, or poverty (P trend ≤ .051) and income, employment, or poverty (P trend ≤ 0.059), respectively. Crude Cox models showed black men had higher BCR risk (hazards ratio = 1.20, 95% confidence interval = 1.05-1.38, P = .009) that persisted after adjustment for covariates including SES (hazards ratio ≥ 1.18, P ≤ .040). Higher SES measured by income and poverty were associated with less BCR, but only for black men (P trend ≤ .048).
CONCLUSIONS: Even in an equal-access setting, higher SES predicted lower PSM risk, and race persisted in predicting BCR despite adjustment for SES. Low SES black patients may be at greatest risk for postprostatectomy BCR.