The promise of scientific and medical innovation often comes with a downside: improvements in care benefit some people, but not all. Without concerted effort, that is exactly what could happen with liquid biopsy — an evolving technology aimed at improving cancer care using just a few milliliters of blood or other body fluids.
Liquid biopsy technologies are maturing at a rapid pace. They are already being used as a precision medicine tool, helping clinicians match a patient’s cancer to targeted therapies. Additional uses are on the horizon. The Food and Drug Administration’s approval this week of a liquid biopsy test for colorectal cancer is the latest step forward in the effort to make this approach part of the existing toolbox to detect hidden cancer. Liquid biopsy is also demonstrating promise in monitoring how individuals are responding to treatment and in detecting cancer recurrence.
Experts are appropriately highlighting the need for additional research to understand the potential clinical value and optimal use of liquid biopsies in these areas, including early detection and monitoring treatment and recurrence.
As uses of liquid biopsy grow, and new uses inch closer to the clinical setting, the risk they may exacerbate existing health disparities, or create new ones, is coming into focus. Now is the time for thoughtful collaboration among key stakeholders to address the issue.
Using liquid biopsy to match people with cancer to the treatments that are right for them can help address cancer disparities. But research is already showing that liquid biopsy for selecting treatment is falling into well-established patterns of use — and non-use. One recent study disappointingly demonstrated a 10-percentage point difference between Black and white people with lung cancer receiving next-generation sequencing-based tumor profiling. Such tests are an indispensable gateway for people to be treated with targeted therapies; when an individual isn’t tested, their prospects of accessing matched treatments are low. That 10% disparity in tumor profiling sets up the next chapter in cancer disparities, with the clinical benefits of newer treatments accruing to only some patients rather than benefiting all individuals with cancer.
Working now to prevent disparities in future clinical applications of liquid biopsies is critical. Industry, patient organizations, health care providers, and payers must anticipate and prepare for upcoming innovation, to head off tomorrow’s access gaps and ensure guideline-supported care for all. If the question of access is deferred until there is widespread use, disparities may have already taken root and “widespread use” will actually mean disproportionate adoption among patient populations who typically have fewer barriers to accessing new health care advances.
To tackle these challenges, we collaborated with colleagues working with the BLOODPAC consortium, a nonprofit organization focused on accelerating the development and accessibility of liquid biopsy assays, to publish a paper detailing barriers to access and describing a roadmap for equitable implementation of liquid biopsy testing.
Disparities in access appear to be fueled by multiple factors, and the evolving nature of liquid biopsy’s different applications may pose one of the greatest challenges in adoption. We found that lack of familiarity with liquid biopsy, uncertainty around test performance, and inconsistent payer coverage are barriers to use that affect everyone with cancer. We also identified barriers specific to underserved populations, including discrimination in health care, patient mistrust in the medical establishment lending to leeriness of new technology, and inconsistent or inaccessible terminology that hinders communication and potentially discourages uptake of liquid biopsy. Barriers facing underserved populations are compounded by awareness gaps among health care providers, provider bias, and a health care system that does not adequately support all patients.
The disparities we identified, and others, are why the discussion about access to liquid biopsy is so essential. The technology doesn’t just have the potential to generally improve cancer care today. The evolving utility of these tests to help promote early detection and to detect recurrences earlier means liquid biopsy can serve as a tool to specifically combat cancer disparities. Because they use samples of blood, urine, or other body fluids to look for signs of cancer, liquid biopsy tests can be performed outside of specialized health care and imaging centers, and in places more accessible to patients, such as mobile health clinics. Closer proximity to care can reduce the burden of travel, costs, and time taken off work for patients. Collecting blood or other fluids is inherently less painful or invasive than a tumor biopsy, reducing the psychological and physical burdens that cancer care places on individuals.
As technologies advance, liquid biopsy tests will continue to transform early detection efforts by expanding the number of cancers that can be caught early through routine checks, beyond the current handful, and offering second-line options to individuals who are not able to access guideline-recommended standard cancer detection tests. Given what we know about the economic burden of a late diagnosis, the hope is that liquid biopsy could create cost savings for patients and health care systems through earlier detection, reduction in invasive diagnostic procedures, reduced need or frequency of tumor biopsies, and more effective cancer treatment selection and recurrence monitoring.
Through a comprehensive understanding of the barriers to access, and by holistically addressing these challenges, the cancer community can ensure that these precision medicine tools benefit all patients. We see three essential steps to getting there:
First, developers of liquid biopsy tests must work with diverse and representative populations — in clinical trials and real-world studies — so results apply to all people with cancer. This can generate greater trust and credibility that the results are relevant to all eligible patients and help inform the larger discussion of liquid biopsy’s role in value-based care.
Second, as more assays come to market, receive FDA authorization, and enter the standard-of-care, it’s especially important that payers engage in the access discussion to inform how they cover liquid biopsy tests. The decisions payers make regarding covering tests will influence whether liquid biopsy can be appropriately used to close gaps in cancer care and outcomes. Consortia like BLOODPAC can help understand what the majority of payers are covering, review the available evidence, and identify and fill in gaps that are limiting coverage. In addition, to optimize patient access, collaboration between payers, clinicians, patient groups, and industry will be needed to ensure that prior authorization or cost-sharing measures frequently used by payers do not become stumbling blocks for appropriate use.
Third, patient and provider education will require time and attention from all sides. Developing the right educational tools and effectively reaching patients and their care providers will require gathering real-world perspectives from community leaders and health care centers. In particular, understanding and alleviating privacy concerns and effectively communicating what tests can — and cannot — tell patients and their health care providers is necessary for building trust in an emerging technology. This work will require creating educational materials using language patients can understand, in English, Spanish, and various other languages. Clinicians play an essential role in the adoption curve of these technologies, and resources that are informed by patient and clinician input will support their decision-making.
Each of these goals is a tall order, which is why it’s important to leverage the space for conversation and collaboration that BLOODPAC has provided since it began working as a pilot project under the Cancer Moonshot in 2016. People with cancer don’t have the luxury of time to wait for health system stakeholders to reinvent the wheel, and the pace of progress in liquid biopsy is being closely shadowed by emerging disparities. It is vital to strategically and collaboratively address the inequities that exist today and to prevent new ones from emerging as new uses become standard of care. We hope that entities across the cancer ecosystem — researchers, industry, health care providers, payers and patient advocates — will use the recently published roadmap and frameworks that already exist to address emerging gaps and target disparities that have been the norm for too long.
Gebra Cuyun Carter, Ph.D., M.P.H., is the senior director of health economics and outcomes research at Exact Sciences. Caitlin Kubler, M.S., is the senior director of policy and advocacy at the Prevent Cancer Foundation. Both authors are members of BLOODPAC’s Accessibility Working Group.