Advancing Precision Oncology: Pharmacist Perspectives on MRD Testing and Diagnostic Innovation

At the San Antonio Breast Cancer Symposium in San Antonio, Thomas P. Slavin Jr., MD, MBA, FACMGG, DABMD, discussed in this Q&A with Pharmacy Times how rising cancer incidence among younger adults is accelerating the integration of precision diagnostics including circulating tumor DNA (ctDNA) minimal residual disease (MRD) testing and hereditary cancer panels into routine oncology care. He noted that younger, tech-savvy patients are increasingly engaged in these tools, creating greater need for pharmacist involvement in education, interpretation, and therapy support.

Dr. Slavin highlighted that the demand for personalized, technology-driven care is rapidly advancing innovation in cancer diagnostics. Emerging platforms such as the Haystack MRD Test and multi-cancer early detection technologies are enabling earlier identification of molecular disease signals and more tailored treatment strategies.

Pharmacy Times: As cancer incidence rises among younger adults, how do you see pharmacists playing a more central role in guiding patients through precision diagnostics—such as ctDNA MRD testing and hereditary cancer panels—especially as these tools become more integrated into routine oncology workflows?

Thomas P. Slavin Jr., MD, MBA, FACMGG, DABMD: It goes without saying that pharmacists play a crucial role in a cancer patient’s care team, and that will only continue to grow as cancer incidence rises among younger people. Younger people may have different expectations of how they will interact with their care team, such as potentially desiring more personalized touchbases, and may prove to be more up-to-speed on the latest diagnostic tests such as ctDNA MRD testing and hereditary cancer panels. While this is only conjecture, what’s clear is that different approaches will be required for different audiences, and pharmacists can help lead the way by being the patient’s trusted medication resource. Whether inpatient, ambulatory, specialty, or in industry or academic settings, all pharmacists have a role to play in ctDNA MRD, which has potential to improve monitoring of patients during and following treatment for solid tumor cancers.

Pharmacy Times: You’ve spoken about how younger cancer patients are driving demand for personalized, tech-enabled cancer care. How is this shift influencing innovation in cancer diagnostics, and what changes do you anticipate in the standard diagnostic pathway over the next few years as this cohort grows?

Slavin: Younger patients, as well as tech-savvy older patients, are driving demand for new patient care modalities. This, combined with a more tech-savvy generation of researchers, is pushing cancer diagnostics forwards in exciting ways, especially MRD testing. Depending on what you look at, 40-80% of oncologists have used this type of testing (ctDNA MRD) in their practice at this point. People have pretty much every question they want answered at their fingertips now, especially with AI. We're entering into a whole different field of informed patients who can start thinking about these types of tests and are they getting the right treatment. This will only accelerate over the next few years, as tests like the Haystack MRD Test from Quest Diagnostics (which is a tumor-informed, next-generation MRD test that detects ultralow levels of ctDNA to uncover residual or recurrent disease with exceptional accuracy in patients treated for cancer), new technologies for cancer treatment matching, as well as Multi-Cancer Early Detection based on cancer genetic fingerprints push the industry forward by offering laboratory tools that can spot cancer signals and features that might otherwise be missed. 

Pharmacy Times: With increasing adoption of MRD testing to inform treatment escalation or de-escalation, what are the most important considerations pharmacists should understand when interpreting MRD assay results to support therapy optimization, patient counseling, and adherence?

Slavin: When it comes to new modalities like MRD testing, patient education is more crucial than ever. Pharmacists are uniquely equipped to explain to patients why a certain therapy is being selected for them and the specific steps they need to adhere to it. At Quest Diagnostics, we aim to provide a test that demonstrates both clinical impact. Our ultradeep MRD sequencing reads each molecule up to 1 million times, delivering results that may help guide critical treatment decisions. Pharmacists should also be aware that MRD testing is relatively new. However, research partnerships are underway to study the test, including with Rutgers and Mass General Brigham (see press releases below).^1,2

Pharmacy Times: As MRD testing becomes more widely used across solid tumors, what do you see as the biggest opportunities—and limitations—of ctDNA-based MRD assays in real-world practice, particularly regarding treatment selection, clinical trial matching, and earlier intervention strategies

Slavin: The opportunity for MRD testing to help clinicians understand their patient’s particular cancer situation is incredible. From early detection of recurrence, to treatment monitoring, to personalized tumor tracking, to accelerating clinical trials and producing insights that drive biopharma pipeline development, to reduction in unnecessary treatment. However, MRD testing is still relatively new, having only been available since 2020. It's early in its lifecycle of adoption, which creates certain challenges: 

• Diagnostic complexity: The increasing number of diagnostic options can be confusing for patients, not understood in totality by the extent of the care team, or reimbursed yet by insurance. MRD is not yet commonly supported across major guidelines, like the NCCN, despite evidence of clinical utility in many cancer types.
• Cost: The financial barrier can be significant for some patients particularly if health plan reimbursement is not available. Many companies offer some type of financial assistance for patients who qualify.
• Global access: Availability and adoption of MRD testing varies significantly between countries, with testing in the United States being more accessible currently compared to other regions. Europe has been slower to adopt MRD tests than the U.S. However, Quest collaborated with a laboratory in Germany to support their ability to offer MRD testing, based in part on our Haystack technology. We also provide global access through a network of partner laboratories.

REFERENCES:

1. Haystack Oncology and Rutgers Cancer Institute Collaborate in a Clinical Study to Examine Haystack MRD as a Guide for Post-Surgical Treatment for Lung Cancer. Questdiagnostics.com. Published September 22, 2025. Accessed December 12, 2025. https://ir.questdiagnostics.com/press-releases/press-release-details/2025/Haystack-Oncology-and-Rutgers-Cancer-Institute-Collaborate-in-a-Clinical-Study-to-Examine-Haystack-MRD-as-a-Guide-for-Post-Surgical-Treatment-for-Lung-Cancer/default.aspx

2. Mass General Brigham Launches Two Clinical Trials to Study Haystack MRD ctDNA as Guide for Post-surgical Treatment for Two Cancer Types. Questdiagnostics.com. Published August 7, 2025. Accessed December 12, 2025. https://ir.questdiagnostics.com/press-releases/press-release-details/2025/Mass-General-Brigham-Launches-Two-Clinical-Trials-to-Study-Haystack-MRD-ctDNA-as-Guide-for-Post-surgical-Treatment-for-Two-Cancer-Types/default.aspx