Multicenter Comparison of 17-Gene Genomic Prostate Score as a Predictor of Outcomes in African American and Caucasian American Men with Clinically Localized Prostate Cancer

Are high-risk prostate cancer patients being treated equally? The impact of PSA

BACKGROUND

Patients with high-risk (HR) prostate cancer (PCa) represent a heterogeneous group, however, current treatment guidelines do not consider their specific features. The objective of this study was to evaluate treatment trends and outcomes in HR patients defined by PSA alone and otherwise low-risk features.

METHODS

Using the National Cancer Database, we identified patients diagnosed with HR PCa between 2010 and 2016. A study group of patients defined by PSA >20 ng/ml alone and otherwise low-risk features, was compared to a group of HR patients defined by Gleason score or stage. We compared treatment rates over time, the use of concomitant androgen deprivation therapy (ADT), and overall survival (OS). Examination of treatment trends was done using a Z-test analysis. A Kaplan-Meier survival analysis was used to determine 5-year OS with the Log-rank test for comparison. Statistical analyses were completed using R Version 3.5.2.

RESULTS

We identified 5,652 patients in the study group and 71,922 in the comparison group. Only 6.8% of the study group had disease ≥cT2, compared to 43.7% in the comparison group. In the study group, 12.5% (709), underwent active surveillance (AS), 36.4% (2,055) radiation therapy (EBRT) and 51.1% (2,888) radical prostatectomy (RP), while the rate of AS, EBRT, and RP in the comparison group were 0.3% (191), 43.0% (30,928), and 56.7% (40,803), respectively. Over the study period, adoption of AS increased from 6.2% in 2010 to 25.0% in 2016 in the study group (P< 0.001), but not in the comparison group. In patients undergoing EBRT, ADT treatment increased from 2010 to 2016 in both groups, though by 2016 only 45.3% of patients in the study group and 86.3% in the comparison group received ADT. The 5-year OS was 93.7% (95% CI 92.8-94.6) in the study group and 89.7% (95% CI 89.2-90.1) in the comparison group (P< 0.001).

CONCLUSIONS

Men with HR PCa defined by PSA with otherwise low risk features present at an earlier stage and receive less aggressive therapy than other HR patients. Despite increased rates of AS and decreased use of ADT, these patients appear to have improved survival when compared to other HR patients. These findings suggest that not all HR patients will benefit from aggressive definitive treatment.

The 17-Gene Genomic Prostate Score Test Is Prognostic for Outcomes After Primary External Beam Radiation Therapy in Men With Clinically Localized Prostate Cancer

PURPOSE

The Oncotype DX Genomic Prostate Score (GPS) assay has been validated as a strong prognostic indicator of adverse pathology, biochemical recurrence, distant metastasis (DM), and prostate cancer (PCa)-related death (PCD) in men with localized PCa after radical prostatectomy. However, it has yet to be tested in men undergoing external beam radiation therapy (EBRT), for whom assessing PCa progression risk could inform decisions on treatment intensity. We analyzed whether GPS results are associated with time to biochemical failure (BCF), DM, and PCD after EBRT in men with localized PCa and whether the association is modified by race.

METHODS AND MATERIALS

We conducted a retrospective study of men with localized PCa treated with EBRT at the VA Health Care System in Durham, NC from 2000 to 2016. Study endpoints were time to BCF per the Phoenix criteria, DM, and PCD. The association of GPS results, per 20-unit increase or dichotomous variable (0-40 vs 41-100), was evaluated with each endpoint using univariable and multivariable Cox proportional hazards models. Results were then stratified by race.

RESULTS

A total of 238 patients (69% Black) met the eligibility criteria. Median follow-up for patients who did not experience BCF was 7.6 years. GPS results per 20-unit increase were significantly associated with BCF (hazard ratio [HR], 3.62; 95% confidence interval [CI], 2.59-5.02), DM (HR, 4.48; 95% CI, 2.75-7.38), and PCD (HR, 5.36; 95% CI, 3.06-9.76) in univariable analysis. GPS results remained significant in multivariable models adjusted for baseline clinical and pathological factors, with HRs being similar to the univariable analysis. There was no significant interaction between the GPS assay and race (P = .923). HRs for BCF were similar in Black men (HR, 3.88; 95% CI, 2.40-6.24) versus non-Black men (HR, 4.01; 95% CI, 2.42-6.45).

CONCLUSIONS

Among men treated with EBRT, the GPS assay is a strong, independent prognostic indicator of time to BCF, DM, and PCD, and performs similarly in Black and non-Black men.

Racial disparities in prostate cancer among black men: epidemiology and outcomes

Prostate cancer has the widest racial disparities of any cancer, and these disparities appear at every stage of the cancer continuum. This review focuses on the disparities in prostate cancer between Black and White men, spanning from prevention and screening to clinical outcomes. We conduct an expansive review of the literature on racial disparities in prostate cancer, interpret the findings, and discuss areas of unmet need in research. We provide an overview of epidemiologic concepts necessary to understanding the current state of prostate cancer disparities, discuss the complexities of studying race, and review potential drivers of disparities in incidence and mortality. We argue that the cause of this disparity is multifactorial and due to a combination of social and environmental factors. The path forward needs to focus on enrolling and retaining Black men in prostate cancer clinical trials and observational studies and identifying potential interventions to improve prevention and clinical outcomes in Black men.

Genomic biomarkers to guide precision radiotherapy in prostate cancer

Our ability to prognosticate the clinical course of patients with cancer has historically been limited to clinical, histopathological, and radiographic features. It has long been clear however, that these data alone do not adequately capture the heterogeneity and breadth of disease trajectories experienced by patients. The advent of efficient genomic sequencing has led to a revolution in cancer care as we try to understand and personalize treatment specific to patient clinico-genomic phenotypes. Within prostate cancer, emerging evidence suggests that tumor genomics (e.g., DNA, RNA, and epigenetics) can be utilized to inform clinical decision making. In addition to providing discriminatory information about prognosis, it is likely tumor genomics also hold a key in predicting response to oncologic therapies which could be used to further tailor treatment recommendations. Herein we review select literature surrounding the use of tumor genomics within the management of prostate cancer, specifically leaning toward analytically validated and clinically tested genomic biomarkers utilized in radiotherapy and/or adjunctive therapies given with radiotherapy.