PREDICTIVE VALUE OF PSA KINETICS ON RISK OF PROSTATE CANCER VERSUS INFLAMMATION IN AN AFRO-CARIBBEAN POPULATION: A SINGLE INSTITUTION BASED RETROSPECTIVE STUDY IN AFRO-CARIBBEAN POPULATION

Abstract

Introduction

The change in Prostate Specific Antigen (PSA) over time, known as PSA velocity (PSAV), has been proposed as a measurement for improving the specificity of PSA monitoring for prostate cancer screening; however, its utility is controversial. Some studies use PSA doubling time (PSADT) as a readout of biochemical and clinical progression. Studies suggest that the validity of PSAV thresholds varies depending on the demographics of the patient population. Few studies investigate how PSAV and PSADT can be used to stratify prostate cancer risk in black populations. Black men have the highest incidence of prostate cancer out of any group in America. This retrospective study aims to compare PSAV and PSADT in patients who received prostate biopsy with pathology results of inflammation versus cancer to determine how PSAV and PSADT impact the risk of prostate cancer in a predominantly Afro-Caribbean patient population.

Methods

Prostate biopsies from Kings County Hospital, Brooklyn, New York, from 01/2018 to 04/2024, were retrospectively reviewed and recorded in the REDcap database. Patients with three PSA values at least 18 months, with six months between each, were included. Pathology results were classified into cancer (N=155) and inflammation (N=70). The cancer cohort was stratified to adjust for treatment (N=126, 81%). PSAV calculation used untransformed PSA values that met the previously mentioned inclusion criteria. The cancer cohort (calculated before treatment, N=50) was compared to the inflammation group (N=64). PSA doubling times (at least two PSA values, three months apart) were also compared between the cancer cohort pre- and post-treatment (N = 68, 63) and the inflammation cohort pre- and post-biopsy (N = 34, 39) when PSAV could not be calculated. Odds ratio, sensitivity, and specificity were calculated using several PSAV and doubling time thresholds.

Results

Increasing threshold PSAV increased specificity in identifying a cancer patient (Figure 1). However, returns were limited as using a PSAV threshold of 2.00 ng/mL/Yr, 16 of 50 (32%) cancer patients met the threshold. This contrasts with 36 of 50 patients (72%) who met the lowest threshold. 0.65 ng/mL/Yr yielded the highest odds ratio (OR = 3.97, 95% CI [1.81, 8.71]) amongst results where p < 0.05. When comparing PSA doubling time using values of less than 6 and 10 months as thresholds between pre-treatment cancer and pre-biopsy groups, there were no significant findings. However, comparing post-treatment cancer cohort to post-biopsy inflammation, both a cutoff of 6 (OR = 3.33, 95% CI [1.44, 7.67]) and 10 months (OR = 3.44, 95% CI [1.49, 7.93]) showed similar significant findings (Table 1).

Conclusions

PSAV has the potential to increase the specificity of PSA monitoring, particularly in black populations that have a high incidence of disease. Our data suggests that when taken together with PSA value, PSAV can improve the specificity of PSA monitoring in an Afro-Caribbean population. PSADT may be helpful in the decision to perform or repeat a prostate biopsy if the initial biopsy showed inflammation in this patient population. However, our research suggests that PSADT does not help estimate the risk of cancer in individuals who have never received a biopsy.