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Genetics, genomics, and biomarker applications have become critical components of prostate cancer care, and new developments in precision medicine promise to further improve outcomes -- but unfortunately not for all patients, noted authors of a review in the .

Risk assessment, diagnosis, and treatment have all benefitted from molecular applications. "Their value in providing optimal care in these settings is clear, yet not all men benefit equitably from these tools for a variety of reasons," wrote Timothy Rebbeck, PhD, of Dana-Farber Cancer Institute in Boston, and colleagues.

Their review discusses the challenges that clinicians and healthcare systems face in implementing treatment advances equitably. Rebbeck, who is director of the Zhu Family Center for Global Cancer Prevention for Harvard T.H. Chan School of Public Health and Dana-Farber's Center for Global Health Equity, elaborated on some of these topics in the following interview.

A chief barrier to equitable treatment is that clinical trials tend to include mostly white patients. How can this lead to suboptimal care for nonwhite patients?

Rebbeck: Diversity in clinical trial participants is critical because we know that when a treatment, screening test, technology, or other medical modality is developed in a narrow population, the resulting intervention may not be as effective for populations not included in the original research. This is not limited only to racial differences, but also to any characteristics of patients who represent the broader population in terms of health conditions, including health status, tumor, molecular signatures, and other features that may be relevant to treatment response.

Thus, a treatment may not be optimally transportable from the population in which it was discovered (i.e., the original clinical trials) and its future broader use in the population. This may reflect not only efficacy of the treatment, but also treatment toxicities.

Very importantly, we know that when therapies are developed in narrowly defined populations and more diverse patient groups are not included, the treatments don't work as well for anyone – including the majority population that was originally studied. Thus, diverse data is required to optimize efficacy and effectiveness, and this can be achieved through inclusion of diverse populations in drug discovery and testing.

What would it take to achieve true diversity in clinical trial research, and is anyone actually trying to achieve this?

Rebbeck: There are numerous initiatives underway around the country to enhance the diversity of clinical trial participants. This is happening in major cancer centers, as well as in the community oncology network in which clinical trials are undertaken outside of large cancer centers.

Many best practices have been developed to increase inclusivity of enrollment in clinical trials. Perhaps the most important of these address the issue that medically underserved populations tend not to be asked to participate in clinical trials; this may be due to clinician biases about whether a patient will accept being in a clinical trial, whether they will have the ability to complete the trial, and other factors that have been shown many times over not to be the case.

For example, when Black patients and white patients are asked to participate in a clinical trial, they agree at approximately the same rate. But Black patients are less likely to be seen in centers that offer clinical trials, and they are less likely to be asked to participate in a clinical trial.

Insurance or other healthcare barriers limit access to state-of-the-art approaches for some patients. Is there anything clinicians can do to help overcome these kinds of barriers?

Rebbeck: It is true that insurance can represent a barrier in access to advanced treatments and clinical trials. Most cancer centers will accept any patient who comes into their care, even if it means providing indigent care. However, many insurers don't allow their covered patients to go to "high cost" centers, where clinical trials may be offered. There are examples where major cancer centers have negotiated with insurers to allow their patients to access these state-of-the-art treatments and clinical research.

There are numerous resources that identify clinical trials for which patients may be eligible, even if they are not being offered at the center where they are seen. Clinicians are mostly aware of these, but it is often difficult for a patient to get access to a clinical trial, particularly if the trial is offered a long distance away, or if the eligibility criteria are extremely strict and do not include, for example, patients with comorbidities that may be more likely in some medically underserved groups.

Many traditionally underserved patients appear late to the healthcare system with advanced disease and so miss the opportunity to benefit from the newest diagnostic and risk-assessment tools. What can be done to encourage these patients to see a doctor earlier?

Rebbeck: There are many opportunities for cancer screening and other early detection tools that will help diagnose cancer earlier. These include mammography, colonoscopy, Pap smears, and low-dose CT screening for lung cancer. For many of these, there are free screenings, help with screening navigation, and other facilities and resources that help medically underserved people to access these tools.

But it remains the case that many individuals have limited access to medical care, insurance constraints, or time constraints due to work or family issues. These individuals either delay or do not have access to timely interventions. Education is certainly an important part of addressing this, but navigation of patients can play an important role as well. Mobile mammography, assistance with transportation or childcare, and other patient resources are available to help those with care-access issues.

Read the review here and expert commentary about it here.