ASCO 2021: Are We Making Progress in Addressing Disparities in Prostate Cancer?

( Dr. Peter Black reviewed the prior three abstracts, focused on addressing the increased incidence and mortality in African American men (AAM) with prostate cancer. He framed his discussion around points brought up by a previous presenter, that prostate cancer outcomes could be equivalent by race if all patients received a timely diagnosis, had adequate staging and risk stratification, and received equitable and correct treatment delivery.

The first study by Qiao et al looked at how PSA screening might be more appropriately tailored to AAM, as current trials looking at the benefit of PSA screening did not adequately represent AAM. Using a cohort of 4,726 men diagnosed with prostate cancer through the VA healthcare system, they found that higher PSA screening amounts were associated with lower Gleason score, lower PSA and less metastatic disease at diagnosis. This translated to lower prostate cancer-specific mortality at 7 years (2.2% for high screening versus 4.0% for low screening) and 10 years (3.1% versus 6.6%). This study shows that in AAM aged 40-55 years, less PSA screening is associated with adverse disease characteristics. The limitations of this study are that it was retrospective, included only men diagnosed with prostate cancer, was limited to the VA population, and the lead time bias adjustment used by the investigator has not been fully validated in younger patients. Nevertheless, this presentation suggested that more PSA screening would likely have an impact on cancer-specific mortality in AAM, though the optimal number of screens and age to start screening remains unclear.

Dr. Black then reviewed the second study by Dr. Yamoah and colleagues examining whether genomic classifiers such as Decipher could improve risk stratification beyond current NCCN guidelines for AAM. The Decipher genomic classifier has been validated in non-AAM in a few contexts, but its ability to augment risk stratification in AAM is largely unknown. Several retrospective studies have suggested that various genomic classifiers perform similarly regardless of race, but this has not been proven prospectively. In this study of 102 AAM and 105 non-AAM that were CAPRA-score risk matched, the Decipher molecular classifier identified a subset of NCCN clinically low or favorable-intermediate risk that had high genomic risk of developing distant metastases. The implications of this deviation in risk score on clinical outcomes remains to be seen, but suggests utility of genomic classifiers in augmenting risk stratification-based treatment in clinically localized prostate cancer.

Next, Dr. Black reviewed the study by Dr. Mahal and colleagues that aimed to survey the genomics of advanced prostate cancer, the utilization of clinical genomic profiling in patients of different ancestral background, and how these findings were used in clinical care. The authors found largely similar rates of alterations in genes that have therapeutic implications, regardless of race. African ancestry patients were less likely to be enrolled on a clinical trial in the studied data set, and genomic profiling was used later in disease course. The data from Dr. Mahal and colleagues suggests that precision medicine tools may benefit AAM and non-AAM equally, so long as they are equally available to both patient populations.

He ended his discussion by asking whether the field is making progress in addressing disparities in prostate cancer. He suggested that we are identifying and documenting disparities through research, and these disparities are receiving national attention. Change implementation is still ultimately required to continue to work towards achieving equity in the care of patients with prostate cancer.

Presented by: Peter C. Black, MD, Urologic Oncologist and Khosrowshahi Family Chair, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC

Written by: Alok Tewari, MD, PhD, Medical Oncologist at the Dana-Farber Cancer Institute, at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, Virtual Annual Meeting #ASCO21, June, 4-8, 2021