Substantial Gleason reclassification in Black men with national comprehensive cancer network low-risk prostate cancer - A propensity score analysis

Abstract

Background: Emerging evidence suggests that a subset of Black men with National Comprehensive Cancer Network (NCCN) low-risk prostate cancer (PCa) may harbor high volume and genomically aggressive disease. However, limited, and ambiguous research exist to evaluate the risk of extreme Gleason reclassification in Black men with low-risk PCa.

Methods: This retrospective cohort study included 45,674 low-risk PCa patients who underwent prostatectomy and were not on active surveillance, from National Cancer Database (NCDB). A propensity score matched-pair design was employed, and the final cohort was limited to 1:1 matched 12,340 patients. Gleason score reclassification was used as primary endpoint. As such, any migration to pathologic Gleason score ≥7(3 + 4) was identified as overall, whereas migration to ≥7(4 + 3) was defined as extreme reclassification. A conditional Poisson regression model was used to estimate the risk of reclassification. Whereas spline model was used to estimate the impact of increasing time to treatment as a non-linear function on Gleason reclassification between race group.

Results: Upon matching there were no differences in the baseline characteristics between race groups. In a matched cohort, higher proportion of low-risk Black men (6.6%) reported extreme reclassification to pathologic Gleason score than White men (5.0%), p < 0.001. In a conditional Poisson regression model adjusted for time to treatment, the risk of overall (RR = 1.09, 95% CI, 1.05-1.13, p < 0.001) and extreme (RR = 1.30, 95% CI, 1.12-1.50, p = 0.004) reclassification was significantly higher in Black men as compared to their White counterpart. In spline model, the probability of Gleason reclassification in Black men was elevated with increasing time to treatment, especially after 180 days (53% vs. 43% between Black and White men).

Conclusion: Risk of Gleason score reclassification is disparately elevated in Black men with low-risk PCa. Furthermore, time to treatment can non-linearly impact Gleason reclassification in Black men.