Recently at the American College of Gastroenterology’s 2021 Annual Scientific Meeting, Dr. Hee Cheol Kim, Professor of Surgery at Samsung Medical Center in Seoul, South Korea, presented an abstract detailing results from a study on Guardant Health’s LUNAR-2 blood test for colorectal cancer (CRC). It was found that the test had a sensitivity (percent of CRC patients identified as having CRC) of 96% and a specificity (percent of patients without CRC as not having CRC) of 94%.
LUNAR-2 is a multimodal circulating tumor DNA (ctDNA) blood test. ctDNA is the tiny amount of DNA from cancer cells that moves freely in the bloodstream and can be used as a biomarker for cancer diagnosis. Tests for ctDNA are often very sensitive to the smallest amount of tumor DNA and can catch cancer much earlier than physical screening tests such as a colonoscopy.
The efficacy of LUNAR-2 as a CRC screening test was evaluated retrospectively in a cohort of 699 patients with stage 1, 2, or 3 disease. Furthermore, LUNAR-2 was able to identify 90% of asymptomatic patients. This is significant because early detection is strongly associated with improved survival.
Currently, a larger trial with more than 10,000 patients is underway (ECLIPSE study) to further test whether LUNAR-2 is able to diagnose early-stage CRC. Enrollment is expected to be completed later this year.
It is important to have a less invasive and simpler test for CRC screening because of the challenges in adherence to timely screening. Colonoscopy, which is recommended once in 10 years, requires general anesthesia and is considered a medical procedure. Additionally, colonoscopy can be expensive. Stool-based screening tests, such as a FIT test or a FIT-DNA test, have to be done frequently and many people feel uncomfortable getting them done.
Guardant Health Co-CEO AmirAli Talasaz explains in the company press release why a blood test is critical right now, in a post-COVID world. “During the COVID-19 pandemic, screening rates have dropped, wellness visits have declined, and postponements of non-emergency medical procedures have made it harder for people to complete life-saving CRC screening. The study results show that the LUNAR-2 test could provide both patients and physicians with an easy-to-use and highly accurate CRC screening alternative in the form of a blood test.”