Imagine a firefighter at risk of cancer due to exposures or an ataxia-telangiectasia mutation (ATM) carrier who is too young to start pancreatic screening but has high anxiety about the disease. They arrive at their primary care visit asking about a new blood test they saw online that claims to detect dozens of cancers. Their physician is uncertain but notes this is a genomic test and contacts you for help. Do you feel comfortable offering this test? Who should help the patient navigate? 

Multi-cancer early detection (MCED) tests analyze circulating tumor DNA (ctDNA) and other biomarkers to look for signals of cancer, typically in blood. Unlike hereditary tests that evaluate inherited risk, these assays detect methylation patterns and tumor-specific signatures that may suggest cancer is present. Tests vary, and some only detect one type of cancer. Commercial examples include Grail Galleri , Exact Sciences CancerGuard, Guardant Shield and Freenome. 

Most MCED tests are not FDA-approved and are not intended to replace standard-of-care screening, such as mammography or colonoscopy^1,2. At a time when 70% of cancer-related deaths in the U.S. are due to malignancies with no screening test³, MCED tests may help identify cancers with no current screening guidelines, such as head and neck cancers. With growing awareness and marketing, patients are asking about these tests more frequently. 

Public opinion demonstrates a healthy skepticism. Challenges include addressing sensitivity, specificity, variable tumor DNA shedding and positive predictive value. A positive result without correlative imaging can leave patients anxious or trigger an exhausting diagnostic odyssey. A negative result can be misleading if patients don’t understand the limitations. A recent publication concluded there are no controlled studies completed that demonstrate benefits of screening with MCED tests⁴. At our institution, an expert committee reviewed several MCED tests and concluded that, while data are still emerging, they can be offered with careful pretest counseling. 

Genetic Counselors Ordering MCED 

Genetic counselors (GCs) can add unique value for emerging technologies like MCED. Our training in risk assessment, informed consent and results interpretation positions us to guide patients through the complexities of this testing. We are skilled at explaining sensitivity, specificity and test limitations in plain language and preparing patients emotionally for a range of outcomes. Patients often have more time with genetic counselors than in other clinical encounters, creating space to explore motivations and health history and develop a follow-up plan. Pretest counseling can clarify eligibility criteria (such as age, smoking history or family history), set appropriate expectations and reduce the chance of false reassurance or unnecessary alarm. Our skills from hereditary counseling do transfer to MCED counseling. 

At our institution, each GC chose whether they wanted to counsel on MCED testing. These tests can be discussed in addition to standard hereditary cancer counseling and testing since there is some overlap in criteria. Our precision oncology GC oversees MCED test utilization across the system, supporting executive health, occupational health, primary care and oncology departments. For providers who prefer not to order directly, patients are referred to our GCs for germline and/or MCED counseling. Our precision medicine team serves as the point of contact for MCED laboratory representatives and can address patient and clinician FAQs across the health system. GCs collaborated with IS to develop an alert within the electronic medical record that provides information about testing to potential ordering providers. We worked with our medical oncology colleagues to develop a referral protocol for patients with positive MCED results. Because diagnostic workup is outside the GC role, our pathway ensures a smooth handoff to medical oncology.   

The Question of Scope 

Not all genetic counselors agree that MCED testing belongs within our scope of practice. Screening tests have traditionally been ordered by physicians and many feel MCED should be managed like mammograms or colonoscopies. However, not all physicians are familiar with MCED implications or have the time to counsel patients in depth. Several of our primary care physicians have specifically asked for GC involvement, noting that our expertise helps patients make better-informed decisions. Without access to counseling, patients may have unrealistic expectations or instead pursue direct-to-consumer testing, leaving them with results they cannot interpret or act upon. 

The NSGC Scope of Practice⁵ is broad, and many of its core elements could apply to MCED counseling: educating patients, assessing risk, facilitating decision-making and supporting follow-up. Although MCED testing is not included in graduate training, this is not insurmountable. There was a time when noninvasive prenatal testing and BRCA sequencing were also new technologies not included in training. Today they are standard. While there is limited training available, opportunities are expanding, including our annual NSGC conference and education led by the NSGC special interest groups for GC training programs. MCED testing presents an opportunity for professional growth. 

Looking Ahead 

MCED tests are moving quickly into the cancer screening landscape, even as the validation data continues to evolve. The role of GCs is not yet defined, but our skills uniquely equip us to support both patients and providers in navigating this new frontier. As a profession, we can choose to engage. That may mean pursuing additional training, joining institutional review committees, collaborating with oncologists on protocols or building relationships with testing companies. Whatever the approach, our voices are critical in ensuring these technologies are used responsibly. 

Genetic counselors have always adapted at the leading edge of innovation — from the earliest days of BRCA and NIPT testing, and now to our expanding role in somatic oncology. MCED testing represents the next chapter. Whether through counseling, education or system protocol, we have the chance to demonstrate that GCs are not just participants in precision medicine, but leaders in its thoughtful implementation. 

 References

1. Klein, E. A., Richards, D., Cohn, A., Tummala, M., Lapham, R., Cosgrove, D., … & Seiden, M. V. (2021). Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set. Annals of Oncology, 32(9), 1167–1177. https://doi.org/10.1016/j.annonc.2021.05.806 

2. Cohen, J. D., Li, L., Wang, Y., Thoburn, C., Afsari, B., Danilova, L., … & Velculescu, V. E. (2018). Detection and localization of surgically resectable cancers with a multi-analyte blood test. Science, 359(6378), 926–930. https://doi.org/10.1126/science.aar3247 

3. NORC at the University of Chicago. (2025, Dec 22) New Research Highlights Just One in Seven Diagnosed Cancers Found by a Recommended Screening Test. https://www.norc.org/research/library/new-research-highlights-just-one-in-seven-diagnosed-cancers-foun.html#:~:text=However%2C%20many%20people%20do%20not,%25%20of%20cancer%2Drelated%20deaths. 

4. Kahwati, L. C., Avenarius, M., Brouwer, L., Crossnohere, N. L., Doubeni, C. A., Miller, C., Siddiqui, M., Voisin, C., Wines, R. C., & Jonas, D. E. (2025). Multicancer Detection Tests for Screening : A Systematic Review. Annals of internal medicine, 10.7326/ANNALS-25-01877. Advance online publication. https://doi.org/10.7326/ANNALS-25-01877 

5. National Society of Genetic Counselors. (2021). Genetic counselor scope of practice. Journal of Genetic Counseling, 30(6), 1575–1581. https://doi.org/10.1002/jgc4.1466 (accessed 10/2/25) 

6. The authors used an AI tool (ChatGPT) for assistance with editing and refining the tone of this article. The authors maintain full responsibility for the final content.   

---