The Guardant Reveal liquid biopsy test has demonstrated effectiveness in predicting disease recurrence in patients with stage II and higher colorectal cancer (CRC). This was shown through findings from the prospective COSMOS study, which were published in Clinical Cancer Research. The test uses a tissue-free epigenomic approach, with a focus on detecting minimal residual disease (MRD). In 1461 post-treatment samples from 290 patients without recurrence, the test displayed a specificity of 98.2%, with a median lead time of 5.3 months and a maximum lead time of 28.7 months. For patients with a minimum of 16.4 months of follow-up, the sensitivity was 99.1%. Notably, all 342 patients included in the study were evaluated without the need for tissue testing.
Dr Yoshiaki Nakamura, chief of the International Research Promotion Office, Department of Gastroenterology and Gastrointestinal Oncology at the National Cancer Hospital East in Chiba, Japan, and co-lead author of the study, highlighted the value of the test. According to Dr Nakamura, the Guardant Reveal assay allows for sensitive and specific detection of MRD without the logistical complications associated with tissue handling. This reduces the burden on healthcare systems and provides a faster turnaround time for adjuvant therapy decisions, while maintaining performance comparable to tissue-informed methods.
Guardant Reveal is the first test of its kind to detect MRD in colorectal cancer without using tissue. It is also available for breast and lung cancer. The test works by analysing over 20,000 epigenomic regions from a simple blood draw, providing results in less than 10 days. These results support clinicians in making informed decisions in the post-surgery and surveillance phases for patients in the early stages of cancer.
The COSMOS study, which is ongoing, is a multicentre, non-randomised observational study in Japan. It enrolled patients with clinical stage 0 to III CRC, with eligible patients required to be at least 20 years old and scheduled for surgical resection. Those with stage I and higher disease were included in the MRD study. Blood samples were collected at day 28 post-surgery, and every 3 to 6 months afterwards for up to 5 years, or until recurrence. Samples were also taken at the time of recurrence when possible. CT scans were performed every 6 months alongside blood sample collection to monitor patient progress.
The interim analysis included patients with a median age of 70 years, and 44% of the participants were female. Among the cohort, 65% had CRC and 35% had rectal cancer, with most participants having pathologic stage II or III disease. A few patients were excluded from the analysis due to various reasons, including undergoing R2 resection or lacking post-operative timepoints.
Additional data from the study revealed that Guardant Reveal showed a sensitivity of 81% for detecting recurrence in patients with stage II or higher colon cancer and 60% in those with stage II or higher rectal cancer. The test demonstrated 100% sensitivity in detecting recurrence in patients with liver metastases, but lower sensitivity in patients with lung or peritoneum metastases.
Dr Craig Eagle, Chief Medical Officer at Guardant Health, emphasised the significance of these findings. He pointed out that the presence of residual disease after surgery is associated with a higher risk of recurrence in early-stage colon cancer. The COSMOS study supports the use of the Guardant Reveal test to inform decisions regarding adjuvant therapy in stage II or III colon cancer and to detect recurrence earlier than traditional methods during post-treatment surveillance.
The results from the COSMOS study highlight the potential of the Guardant Reveal liquid biopsy test in transforming how clinicians predict and manage disease recurrence in colorectal cancer, providing a more efficient and tissue-free alternative to existing methods.
