Abstract 505P
Background
Presence of MRD after curative-intent surgery for early-stage cancers increases recurrence risk. MRD tests are already available in clinics but real-world usage pattern is infrequently described.
Methods
The 376 patients tested in Asia and Middle East by Guardant Reveal (Guardant Health Inc USA) with CRC (n=284), BC (n=36) and NSCLC (n=56). This assay is a tissue-free MRD test focusing on methylation patterns (in earlier version, included genomic alterations) in cell-free DNA. Patients till 05 Jul 2024 with a test result and documented clinical stage. Samples categorized as post-surgery (within 12 weeks after surgery) or surveillance (>12 weeks after surgery).
Results
The median turnaround time (TAT) from sample reaching the laboratory until report release was 9 days (5-29 days). Total of 284 CRC patients (387 samples) with stage II (n=108), III (n=164), and IV (n=12) disease underwent testing. 62% male. In patients with stage II CRC, 67% of tests were post-surgery, while for stage III CRC, 71% of tests ordered during surveillance. Overall, 21% had MRD detected in their first test, and positivity rate increased with tumor stage (stage II, 11%; stage III, 25%, stage IV: 58%). The 36 patients with breast cancer (43 samples) had stage I (n=1), II (n=22), III (n=10), and IV (n=3). 22% of tumors were HER2 positive disease, 44% were hormone receptor (HR) positive/ HER2 negative, and 31% lacked HER2 and HR. Both stage II and stage III BC test ordered predominantly surveillance (stage II: 64%; stage III 73%). Overall, 22% had MRD detected in their first test. The 56 NSCLC patients (81 samples) had stage I (n=2), II (n=21), or III (n=33). 53% male. Regardless of cancer stage, majority of tests (75%) were ordered during surveillance, up to 5 years after surgery. Overall, 14% had MRD detected in their first test, with the MRD positivity increased with tumor stage: stage I, 0%; stage II, 10%; stage III, 18%. Variation in MRD positivity can be attributed to biological differences across cancer types. Follow-up is ongoing to assess the performance of the MRD tests.
Conclusions
Preliminary real-world experience with a tissue-free test to detect MRD in cfDNA from CRC, BC and NSCLC patients illustrates use patterns in practice with a rapid TAT.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
S. Hsing, S.S. Jain: Financial Interests, Personal, Full or part-time Employment: Guardant Health. All other authors have declared no conflicts of interest.