Blood test holds promise for early cancer detection

In an interim analysis of the K-DETEK study, a noninvasive blood test was able to detect early-stage cancer and identify tumour location in asymptomatic individuals in Vietnam.

“Common screening methods are often invasive, inaccessible, and involve separate procedures to screen individual cancer types. Affordable, accessible, noninvasive multicancer screening tests are needed for early detection, especially in a lower-middle income country like Vietnam,” said senior study author Dr Le Son Tran from Gene Solutions, Ho Chi Minh City, Vietnam.

“Our study has demonstrated the clinical application of a multicancer blood test in a low/middle-income country like Vietnam, where a nationwide cancer screening programme is urgently needed but currently unavailable,” Tran continued. “Beyond detecting cancer signals, our test predicted the tumour location.”

This longitudinal prospective cohort study recruited 10K participants across 14 sites in Vietnam. The interim analysis included 2,795 participants (57 percent female, 51 percent <51 years) with moderate to high cancer risk who had neither clinical suspicion nor a confirmed history of cancer. The researchers evaluated the feasibility of the SPOT-MAS* test, a multimodal liquid biopsy assay developed to test the five most common cancer types in Vietnam (liver, breast, colorectal, gastric, lung), in capturing multiple cancer signals from circulating-tumour DNA (ctDNA) in the blood. [ASCO Breakthrough 2023, abstract 426774]

SPOT-MAS was able to detect cancer in asymptomatic individuals with a positive predictive value of 60 percent. This means that for every 100 people that test positive, 60 have cancer. Negative predictive value for cancer signal detection was 99.89 percent.

SPOT-MAS was also able to predict the location of a tumour with 83.3 percent accuracy. “This allows clinicians to fast-track follow-up diagnostics and guide any necessary treatment,” said Tran.

Early screening is essential for better outcomes

In Vietnam, up to 80 percent of cancer patients are diagnosed at later stages, leading to a low 5-year survival rate. Early screening assays capable of identifying early-stage cancer in high-risk or asymptomatic individuals are needed to achieve better treatment outcomes and reduce mortality.

“Our study provides clinical evidence for the applicability of the SPOT-MAS ctDNA-based assay as a complementary method in early cancer detection,” said Tran.

“Detection of early-stage disease is one of the best ways to cure cancers. Although cancer screening tests currently exist, uptake around the world may be limited by cost, complexity, and scarcity,”  commented ASCO Expert Dr Erica Mayer, in a press release.

The findings demonstrate how a single blood test could identify certain types of cancer, counter the limitations of the current detection tools available, and offer a more convenient alternative.

“These interim results demonstrate that next-generation ctDNA screening holds promise as an early detection tool in Vietnam, although additional validation of the SPOT-MAS assay is needed before this test is ready for clinical use,” Mayer continued.

The investigators are conducting an extension of the study to refine the assay and expand its capacity to identify other cancers. “We are recruiting 10,000 additional participants to further validate the performance of SPOT-MAS in a larger cohort, evaluate participants’ attitude towards cancer screening, and evaluate cost-effectiveness and clinical benefit,” they said.