Development of a comprehensive cell-free DNA (cfDNA) assay for early detection of multiple tumor types: The Circulating Cell-free Genome Atlas (CCGA) study

Background

  • The majority of cancers are detected at advanced stages when treatment burden is high and cure rates are low, thus early diagnosis is likely to improve survival and improve quality of life
  • The use of circulating cell-free DNA (cfDNA) for early cancer detection would require very high specificity in a screening population to avoid false positives and thus unnecessary workups and follow-up testing
  • Available cfDNA-based tests for cancer are almost exclusively focused on detecting later-stage tumors, when ctDNA levels are high
  • Additionally, there are few studies of people without cancer to define specificity in the intended use population
  • Tumor fraction in cfDNA is lower in early stage cancers versus later-stage cancers, and can be low even in some metastatic disease
  • High levels of technical and biological specificity near the molecular limit of detection will be required to detect lowprevalence cfDNA shed from cancer across large genomic regions with confidence
  • This is especially true for a test aimed at detecting multiple cancers from a single blood draw