Predictors of survival outcomes in native sub Saharan black men newly diagnosed with metastatic prostate cancer

Abstract

Background: Though it is well established that black men are at higher risk of prostate cancer (PCa) very little is known about the disease in native sub Saharan black men. Newly diagnosed metastatic PCa patients treated with primary androgen deprivation therapy were identified and predictors of progression-free survival (PFS) assessed.

Methods: Patients diagnosed with metastatic PCa between 2010 and 2015 in a sub Saharan black population were included in the study. Primary outcome measure was PFS defined as time from primary androgen deprivation therapy to clinical progression or death. Demographic, clinical and PSA kinetic variables were evaluated for their prognostic power using Cox proportional hazard regression models.

Results: Seventy-nine patients met the eligibility criteria and were analyzed. Median age, median overall survival and PFS was 69 years, 40 months and 27 months respectively. A PSA nadir >4 ng/mL was found to predict an earlier clinical progression. Median PFS was shorter in those with PSA nadir >4 ng/mL (15 months) compared to those with PSA nadir ≤4 ng/mL (29 months); log rank p value = 0.003.

Conclusions: The PSA nadir achieved following primary androgen deprivation therapy predicts progression-free survival in sub Saharan black men newly diagnosed with metastatic PCa. PSA nadir >4 ng/mL was found to be associated with a more rapid clinical progression.

Keywords: Androgen deprivation therapy; Black men; PSA kinetics; PSA nadir; Prostate cancer; Sub Saharan Africa.

Fig. 1

Waterfall plots of relative PSA decline from baseline for patients with (a) and without (b) clinical progression during study follow-up (median 15 months). A decline of ≥90% was seen in 23 (65.7%) and 37 (84.1%) patients in (a) and (b) respectively. This was not statistically significant (p = 0.06). The bold reference line represents PSA decline of 90%

Fig. 2

Progression-free survival probability of patients with metastatic prostate cancer following primary androgen deprivation therapy. Kaplan-Meier analysis showed significant differences between patients with PSA nadir ≤4 ng/mL Vs > 4 ng/mL, log-rank p-value = 0.003