417P - Early experience in using plasma-only multi-omic minimal residual disease testing in early-stage colorectal cancer patients from Asia and the Middle East

Background

An increasing amount of research suggests that the presence of minimal residual dis-ease (MRD) after curative-intent surgery for early-stage cancers is associated with disease recurrence. Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for MRD assessment in patients with colorectal cancer (CRC) who have undergone surgery or completed adjuvant therapy. MRD tests are already available for use in clinics; however, treatment decisions following MRD results obtained in routine practice are infrequently described.

Methods

In this study, we report on the real-world clinical use of Guardant Reveal, a validated tissue-agnostic MRD assay which assesses genomic mutations as well as methylation sigantures, in the first 82 consecutive patients (102 samples) with CRC tested in Asia and the Middle East.

Results

Overall, 24% of patients had ctDNA detected in their first MRD test, and the frequency of ctDNA positivity increased with increasing tumor stage. Among all ctDNA-positive samples, 48% had evidence of MRD only through the detection of methylation signals, while 26% had both genomic alterations and methylation signals. In patients with stage II CRC, 78% of tests were ordered within 12 weeks after resection, while for patients with stage III disease, 63% of tests were ordered during surveillance. We also describe real-life clinical cases utilizing tissue-agnostic MRD assessment. Most of the physicians included MRD test results in the treatment pla.

Conclusions

Through retrospective analysis of real-world data, we describe how physicians in Asia and the Middle East currently apply a commercially available tissue-agnostic MRD assay in clinical decision-making for patients after surgical resection of colorectal cancer. The addition of methylation assessment to somatic mutation detection contributed to the detection of MRD in samples without mutation. Results from prospective randomized studies will further define the clinical role of MRD detection in resectable CRC. Evidence for tissue-agnostic MRD assays is building across tumor types with continuous improvements in sensitivity and specificity.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

S.S. Jain, S. Hsing, N. Joshi: Financial Interests, Personal, Full or part-time Employment: Guardant Health. All other authors have declared no conflicts of interest.