A Vietnamese prospective study by Hanh Thi-Hue Nguyen, BS, and Le Son Tran, PhD, both of the Medical Genetics Institute and Gene Solutions, Ho Chi Minh City, Vietnam, and colleagues, investigating the feasibility and performance of a circulating tumor DNA (ctDNA) analyzing test in the early detection of the five most common cancer types in Vietnam—liver, breast, colorectal, gastric, and lung cancers—found the test was successful in detecting cancers in asymptomatic individuals, with a positive predictive value of 60%. In addition, the test had nearly 84% accuracy in detecting tumor location.¹ The study was presented during the 2023 ASCO Breakthrough meeting in Yokohama, Japan, and virtually.

Studies have shown that both the incidence of cancer and mortality rates from the disease in Vietnam have tripled over the past 3 decades.² In 2020, more than 182,560 new cases of cancer were diagnosed, and nearly 123,000 people died of the disease.³ In addition, most cases—up to 80%—are diagnosed at stage III or IV, leading to a lower 5-year survival rate compared with other countries with similar disease distributions.³

Study Methodology

The researchers launched a prospective cohort study, K-DETEK (ClinicalTrials.gov identifier NCT05227261), in 13 major hospitals and one research institute in Vietnam to validate their previously developed multimodal liquid biopsy–based assay, Screening for the Presence of Tumor by Methylation and Size (SPOT-MAS), which works by measuring signals of cancer DNA in the blood (including methylation profiles, DNA copy number, size of ctDNA fragments, and the sequence motifs at the end of the fragments). The ctDNA analyzing test is used for the detection of early-stage disease in the five most common cancers among high-risk or asymptomatic individuals, including liver, breast, colorectal, gastric, and lung cancers.

The study recruited 10,000 asymptomatic participants, aged 40 years and older, with follow-up testing at 6 and 12 months. The performance of the ctDNA test was assessed by computing the number of cases with the detection of a signal, including a positive predictive value and accuracy in detecting the tumor tissue of origin.

Results

At the time of the abstract submission, the researchers had analyzed blood samples from 2,795 participants. They found the ctDNA test detected cancers in asymptomatic individuals with a positive predictive value of 60%, with 83.3% accuracy in detecting the tumor location.

In addition, the researchers presented a case report to support the further use of SPOT-MAS as a complementary method of early cancer detection and provide the opportunity for early treatment.

Clinical Significance

“Our study has demonstrated the clinical application of a multicancer test in a low- and middle-income country like Vietnam, where a nationwide cancer screening program is urgently needed but currently not available. Beyond detecting cancer signals, our test predicted the tumor location, allowing clinicians to fast-track the follow-up diagnostic and guide any necessary treatment,” concluded the study authors.

DISCLOSURE: The study authors reported no conflicts of interest.

REFERENCES

1. Nguyen THH, Tran LS: Clinical validation of a ctDNA-based assay for multicancer detection: An interim report from a Vietnamese longitudinal prospective cohort study of 2,795 participants. ASCO Breakthrough. Abstract 135. Presented August 4, 2023.

2. Pham T, Bui L, Kim G, et al: Cancers in Vietnam—burden and control efforts: A narrative scoping review. Cancer Control 26:1073274819863802, 2019.

3. International Agency for Research on Cancer/World Health Organization: Vietnam, Globocan 2020. Available at https://gco.iarc.fr/today/data/factsheets/populations/704-viet-nam-fact-sheets.pdf. Accessed August 1, 2023.