AUA 2021 studies assess racial disparities in prostate cancer

Separate studies presented at the 2021 American Urological Association Annual Meeting found racial disparities in access to sipuleucel-T (Provenge) immunotherapy, tumor biology in prostate cancer, and the effect of the COVID-19 pandemic on receiving treatment for prostate cancer.

The studies were presented in a press briefing moderated by Brian K. McNeil, MD, MBA, FACS, chief of urology at The University Hospital of Brooklyn, vice chair of the department of urology at SUNY Downstate Health Sciences University, and staff urologist at Kings County Hospital Center, Brooklyn, New York.

Access to sipuleucel-T immunotherapy

The first study presented was a multivariate analysis that was conducted to identify potential racial disparities in the utilization of sipuleucel-T (Provenge) immunotherapy in patients with metastatic castration-resistant prostate cancer (mCRPC).1

“We know that Black and Hispanic men have high burden of prostate cancer mortality compared to White men. This has been investigated before, and potential disparities exist in treatment choice, unfortunately,” said author Ali Mouzannar, MD, urology resident at the University of Miami, Florida, working with Chad Ritch, MD, MBA, and colleagues.

For the study, the investigators used the National Cancer Database and a multivariable logistic regression model to determine the predictors of receipt of chemotherapy or immunotherapy. They used these data to analyze annual trends in treatment, comparing utilization by demographic and clinical features.

Patients were less than 70 years of age with prostate cancer, and likely mCRPC (bone only, received hormone therapy, with PSA 50-500 ng/mL), had a Charlson score of 0-2, and must have been treated with chemotherapy or immunotherapy after hormone therapy was initiated. A total of 1238 patients were included in the study: 63% non-Hispanic White, 23% non-Hispanic Black, 7% Hispanic, and the remaining percent other races. Eighty-five percent received chemotherapy (docetaxel) and 15% received immunotherapy (sipuleucel-T).

Results showed that after the FDA approval of sipuleucel-T in 2010 for mCRPC, there was a decrease in chemotherapy treatment and increase in immunotherapy treatment. This, however, occurred mainly in White patients. It was not observed in Black or Hispanic men.

“Further detailed evaluation is necessary to have better insight on the treatment barriers, to improve health care access to all patients, and to ensure that all of them, including minorities, will benefit from novel treatments of metastatic CRPC,” Mouzannar concluded.

Molecular profiling of prostate cancer across races

The second study used microarray analyses to examine whether differences in tumor biology between Black and non-Black patients with prostate cancer contribute to disparate outcomes.²

“While there’s mounting evidence that a multitude of factors contribute to poor prognosis in Black men, including environmental factors, factors related to diet, access to health care, and other socioeconomic factors that disadvantage Black versus non-Black populations, the role of tumor biology in prostate cancer outcomes in Black patients is poorly understood,” explained author Udit Singhal, MD, chief resident at the University of Michigan, Ann Arbor, working with Simpa Salami, MD, MPH, and colleagues.

Between 1991 and 1996, 270 radical prostatectomies were completed in African American men (AAM) and 369 in European American men (EAM) to evaluate the gene expression of 517 prostate cancer-related genes.

Cox proportional hazard regression analyses was performed to identify age, pre-treatment PSA, Gleason grade group (GG) and T-stage. Differential Gene Expression analysis was used to compare genes among the 2 different groups. Gene Set Enrichment Analysis was also performed to determine the most differentially expressed genes.

Results found that AAM with GG1 disease were more likely to have biochemical reoccurrence compared with EAM and that each group has distinct gene profiles. Additionally, genes associated with inflammatory signaling, apoptosis, KRAS signaling, TNFa signaling, and hypoxia are significantly upregulated in AAM, suggesting that biologically AAM with prostate cancer tend to do worse than EAM.

For further research, Singhal added, “I don’t think biology and socioeconomic factors should be looked at in isolation. It’s a noted limitation of our study, in that we looked at just biology and maybe not the socioeconomic factors that drive that biology. So, we need to develop the datasets that look at both congruently, at the same time.”

Inequities within health care

The final study presented compared prostatectomy rates among Black and White patients to assess the impact of COVID-19 on a diverse, multi-institutional regional cohort of community and academic urology practices.³

“Historically, Black Americans experience increased cancer-specific mortality compared to White patients, [but] in prostate cancer specifically…there have been studies that have shown that when access to care is equitable, this gap resolves,” said study author Adrien Bernstein, MD, urology oncology fellow at Fox Chase Cancer Center, Philadelphia, Pennsylvania, working with Andres F. Correa, MD, and colleagues.

Investigators used the Pennsylvania Urologic Regional Collaborative to evaluate men with untreated non-metastatic prostate cancer during the 9-week initial lockdown of the pandemic (March 2020-May 2020). Five sites residing in either Pennsylvania or New Jersey actively contributed to this study.

Fisher’s exact, Pearson’s chi-square, and Wilcoxon’s rank sum compared patient and practice characteristics, such as surgical management and age, comorbidities, risk factors for severe COVID-19 infection, prostate cancer characteristics, and practice considerations. Additionally, a covariate-adjusted, multi-variable logistic regression determined the impact of year and race on surgery.

Results found that Black patients were significantly less likely to undergo surgery (1.3% v 25.9%, P < .001), whereas White patients were 31 times more likely to receive surgical care (OR=03.5, 95% CI 4.07-228.4, P = .001) during lockdown. Black men with non-metastatic prostate cancer were also 94% less likely to undergo surgery compared with Black men prior to the pandemic, and 97% less likely to undergo surgery compared with White men.

“Before the pandemic, we didn’t see a difference [in the level of urologic care between Black and White patients in urban areas],” concludes Bernstein, “and this is a cohort that did have access to care…but when the system gets stressed by an event like a pandemic...we do see that our system is relatively fragile and starts to break down.”

Commenting on the 3 studies in a news release,⁴ McNeil said: “These studies highlight important research in better predicting the behavior and outcomes of prostate cancer in African American men compared to men of other racial and ethnic groups. They also illuminate the systemic inequities and opportunities within health care to eliminate the burden of disease in minority populations.”

References

1. Mouzannar A, Venkatasai SA, Mason M, et al. Racial disparity in the utilization of new therapies for advanced prostate cancer. Paper presented at the 2021 American Urological Association Annual Meeting; September 10-13; virtual. Abstract PD34-03

2. Singhal U, Nallandhighal S, Bolton S, et al. Molecular profiling of prostate cancer reveals increased inflammatory markers and poor clinical outcomes in African American compared to European American men. Paper presented at the 2021 American Urological Association Annual Meeting; September 10-13; virtual. Abstract MP60-05

3. Bernstein A, Talwar R, Handorf E, et al. Racial disparities in prostate cancer treatment in a multi-institutional regional collaborative. Paper presented at the 2021 American Urological Association Annual Meeting; September 10-13; virtual. Abstract PD03-02

4. Racial disparities found among men with prostate cancer. News release. American Urological Association. September 10, 2021. Accessed September 14, 2021. https://www.prnewswire.com/news-releases/racial-disparities-found-among-men-with-prostate-cancer-301373376.html