The early detection of cancer, before the disease has metastasized beyond its initial area of development, holds promise for improving long-term patient survival outcomes.
However, some historical methods for assessing cancer risk, such as fine-needle aspiration biopsies, are costly and inconvenient if not occasionally life-threatening. Safer, faster, more effective, and less expensive cancer detection methods could contribute to reducing the burden of this terrible disease and are a hot area of research.
Chinese scientists from the Taizhou Institute of Health Sciences have demonstrated in a “large-scale restrospective longitudinal study” that five common cancer types- stomach, esophageal, colorectal, lung, and liver cancer- can be detected using a non-invasive blood biopsy up to four years prior to diagnosis, when patients are not yet experiencing symptoms of the disease.
Their research was published in the journal Nature Communications under the title “Non-invasive early detection of cancer four years before conventional diagnosis using a blood test.”
Using patient blood samples derived from the Taizhou Longitudinal Study, the scientists showed that the methylation profiles of circulating tumor DNA could be used to detect these five cancer types “in 88% (95% CI: 80–93%) of post-diagnosis patients with a specificity of 96% (95% CI: 93–98%)” and “in 95% (95% CI: 89–98%) of asymptomatic individuals who were later diagnosed, though future longitudinal studies are required to confirm this result.”
The sensitivity of the test, which indicates the frequency with which an individual who has the disease is correctly diagnosed, was “similar for early-stage and late-stage cancer samples” and “ranged from 75% in colorectal cancers to 96% in lung cancers.”
The Taizhou Longitudinal Study involved the acquisition of blood samples from 123,115 healthy individuals (age range: 25-90) between 2007 and 2014 followed by monitoring for cancer diagnosis through 2017.
Notably, the authors emphasized that their test likely does not identify cancer-free patients that will later develop the disease, but rather patients that “already have cancerous growths but who remain asymptomatic to current detection methods and standard of care, as many cancers do not cause the appearance of symptoms until late in disease development.”
The authors indicated that their assay must be evaluated via a longitudinal prospective study prior to interpreting whether it could have any influence of patient outcomes.
San Francisco-based biotechnology company Biocept has also published research supporting its liquid biopsy platform for cancer detection.
Chen X, Gole J, Gore A et al. (2020) Non-invasive early detection of cancer four years before conventional diagnosis using a blood test. Nat Commun 11, 3475.