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Detecting the unseen: how Haystack MRD™ helps guide cancer treatment decisions

What is MRD?

As cancer treatments become more advanced, a critical challenge remains: determining which patients will benefit from additional therapy and who can safely avoid it. Tracking minimal residual disease (MRD) can help clinicians decide when to act. MRD refers to tiny numbers of cancer cells that may remain in the bloodstream after a cancer diagnosis and treatment. DNA fragments from these cells, known as circulating tumor DNA (ctDNA), can be detected in a blood sample using the Haystack MRD™ test. Haystack MRD™ is purpose-built by pioneers in cancer genomics for ultrasensitive ctDNA detection. Each Haystack MRD™ test is custom-designed to look for up to 50 DNA variants that are unique to a patient’s cancer— and were initially identified in a tumor tissue sample from biopsy or surgery. The presence or absence of these tumor DNA variants in blood can be monitored to help providers guide their cancer patients’ care. 

Haystack MRD™ in practice: an example

Dr Smith is caring for 2 patients with colon cancer, Sally and Joe. Both patients have been diagnosed with stage II colon cancer and undergone surgery. Dr Smith now needs to determine the next steps in their cancer journey. She needs to consider multiple factors in her decision-making in her effort to obtain the best outcome for every patient. Adjuvant chemotherapy may help to destroy residual cancer cells that remain after surgery that, if left untreated, may lead to later cancer recurrence. However, because chemotherapy may have multiple adverse side effects, Dr Smith prefers to avoid using chemotherapy if it is unlikely to benefit her patients. 

Dr Smith’s decision is a complicated one for patients with early-stage cancer because it is difficult to know which patients have truly achieved remission after surgery and which patients have residual disease that could lead to a cancer recurrence without further treatment. To help with this decision, Dr Smith orders the Haystack MRD™ test for both patients to help with her decision. 

Joe’s initial Haystack MRD™ test result is negative, indicating that there was no evidence of residual disease. Based upon the MRD test and all other available evidence Dr Smith does not recommend chemotherapy for Joe since it may cause more potential harms than benefits. Dr Smith and her clinical team will continue to monitor Joe for possible future MRD while engaging in other appropriate clinical surveillance testing to ensure he remains disease-free.

In contrast, Sally’s test result is positive for MRD, indicating a high chance that cancer cells remain in her body. Based on all available evidence including the MRD results, Dr Smith recommends that Sally be treated with adjuvant chemotherapy. During her chemotherapy treatment, Sally continues to be monitored with the Haystack MRD™ test to assess how well her treatment is working. Upon completion of chemotherapy, her MRD result is negative, which is an indication that her chemotherapy treatment was likely successful. Over the next year, Sally continues to have imaging tests to look for recurrent cancer in her body and blood work done for her MRD monitoring. Unfortunately, after a year, Sally’s MRD testing again shows a positive result. This suggests that she is at high risk for clinical recurrence and therefore requires close monitoring to detect and appropriately treat the recurred cancer.
Frequently Asked Questions

Can this test be completed before a cancer diagnosis?
No, this test is not meant to be a screening test for cancer. This test is designed to be used only after a patient has been diagnosed with cancer. 

How is this test personalized to the individual?
The Haystack MRD™ test is tumor-informed, which means that DNA from a patient’s tumor, obtained from a biopsy or surgery, is sequenced using whole exome sequencing (WES). The patient’s white blood cells are also sequenced, allowing us to determine which DNA variants are specific to the patient’s tumor. With this information, we create a personalized panel of up to 50 variants selected from each unique patient’s tumor to look for ctDNA molecules that contain these variants in the patient’s blood.

How often is this test completed?
Following the first (baseline) test, the frequency and duration of a patient’s monitoring blood draws is dependent on several factors, including cancer type, stage, risk features, and treatment. Providers will discuss an optimal testing schedule with each patient. 

Can this test be used for individuals with blood cancer?
No. This test can only be applied for solid tumors. 

Does this test detect hereditary cancer syndromes?
No, this test does not evaluate for inherited variants in genes that can increase someone’s cancer risk. 

To learn more about Haystack MRD™, visit HaystackMRD.com, email info@haystackoncology.com, or call 1.844.966.7050. 

Resources

1. Chidharla A, Rapoport E, Agarwal K, et al. Circulating tumor DNA as a minimal residual disease assessment and recurrence risk in patients undergoing curative-intent resection with or without adjuvant chemotherapy in colorectal cancer: a systematic review and meta-analysis. Int J Mol Sci. 2023;24(12):10230. doi:10.3390/ijms241210230

2. Tie J, Cohen JD, Phil M, et al. Circulating tumor DNA analysis guiding adjuvant therapy in stage II colon cancer. N Engl J Med. 2022;386(24):2261-2272. doi:10.1056/NEJMoa2200075

Authors

Erin Nordquist, MS CGC
Rebecca Johnson, MS CGC

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