Risk of skeletal-related events in mCRPC not associated with race

Among patients with newly diagnosed, bone metastatic castration-resistant prostate cancer (mCRPC), black men did not have a higher risk of skeletal-related events (SREs) and all-cause mortality, according to a retrospective analysis published in Cancer.

“To the best of our knowledge, the prognostic impact of race on the outcomes of men with more advanced forms of prostate cancer remains understudied,” the authors wrote. “We observed no association between Black race and the risk of SREs and overall mortality, indicating that once men develop bone mCRPC, race may not be an adverse prognostic factor.”

The retrospective analysis included patient data from 8 Veterans Affairs (VA) hospitals. Overall, the study included 837 men with bone mCRPC who were diagnosed in the year 2000 or later. Among this population, there were 232 (28%) Black patients and 605 (72%) non-Black patients.

At diagnosis, bone metastases were more common in Black men, with 29% having ≥10 bone metastases compared with 19% of non-Black men (P = .021). The median PSA at diagnosis was also higher in Black men at 41.7 ng/mL versus 29.2 ng/mL, respectively (P = .005).

In the group of patients who did not die, the median follow-up after diagnosis of metastasis was 25.9 months (range, 12.0-46.4). During follow-up, 287 (35%) patients experienced SREs. No difference was observed in the risk of developing an SRE between Black and non-Black patients (log-rank, P = .35). On multivariable analysis, no difference was observed in SRE risk between Black and non-Black patients (HR, 0.80; 95% CI, 0.59-1.07; P = 0.13).

The study also included an analysis of mortality rates from the time of diagnosis of bone mCRPC. In total, 740 men (88%) died during follow-up. On crude analysis, race was found to be unrelated to overall mortality (log-rank, P = .60). Furthermore, there remained no differences on multivariate analyses with regard to overall mortality between Black and non-Black men with bone mCRPC (HR, 0.87; 95% CI, 0.73-1.04; P = .13). However, with the HR being <1, researchers suggested the possibility of better outcomes.

Regarding study limitations, the authors noted that while the inclusion of only patients from VA hospitals was a strength in regard to evaluation of patients who have equal access, it could have possibly made the results difficult to extrapolate to other patient populations. In addition, because these results were observed outside of a clinical trial setting, the various anticancer therapies used to treat patients were not standardized.

“These current data suggest that race does not have a negative prognostic effect in patients with mCRPC,” the authors wrote. “These results are consistent with prior studies from our group using the same cohort, wherein we identified predictors of SREs and race did not enter the model.

“Moreover, along with our mortality data, these data add to the increasing evidence that the greatest benefits to understanding racial disparities in prostate cancer would occur if efforts are focused on cancer development and progression in patients with early-stage disease.”

Reference

Patel DN, Howard LE, De Hoedt AM, et al. Race does not predict skeletal-related events and all-cause mortality in men withcancer. Cancer. 2020;126(14):3274-3280. doi: 10.1002/cncr.32933