Late stage cancers often lack an effective treatment option. Survival rates increase significantly when cancer is identified at early stages, as the tumor can be surgically removed or treated with milder drug regimens. Most cancer types currently lack an effective non-invasive early screening option. A new study published in Nature Communications describes a blood-based screening test that enables early-stage cancer detection.
In the Taizhou Longitudinal Study (TZL), 123,115 healthy subjects provided plasma samples for long-term storage and were then monitored for cancer occurrence. The current study reports the preliminary results of PanSeer, a noninvasive blood test based on circulating tumor DNA methylation, on TZL plasma samples from 605 asymptomatic individuals, 191 of whom were later diagnosed with stomach, esophageal, colorectal, lung or liver cancer within four years of blood draw. They also included plasma samples from an additional 223 cancer patients, plus 200 primary tumor and normal tissues.
The results show that PanSeer detects five common types of cancer in 88% (95% CI: 80–93%) of post-diagnosis patients with a specificity of 96% (95% CI: 93–98%). Furthermore, it has been demonstrated that PanSeer detects cancer in 95% (95% CI: 89–98%) of asymptomatic individuals who were later diagnosed, though future longitudinal studies are required to confirm this result.
In conclusion, the study demonstrated that five types of cancer can be detected through a DNA methylation-based blood test up to four years before conventional diagnosis. This lays the foundation for a non-invasive blood test for early detection of cancer in a high-risk (or average-risk in the future) population.