Critics of LQ for Cancer Screening
Critics of Liquid Biopsy for Cancer Screening are taking to their keyboards to fire their last few bullets against the players in the nascent field of Liquid Biopsy for Cancer Screening.
We’ve seen several people comment on Grail Bio’s move to calculate the value of their MCED Galleri assay as number of years gained with an MCED diagnosis compared to death toll of standard non-screening methods (late-stage cancer incidence). For many critics, AACR is the best time to come up with criticism as it’s when cancer is on the front pages of online publications.
There's ongoing debate in the screening community about whether fatality or overall survival is a reasonable endpoint for such exciting new technology. Critics of LQ MCED are using this to altogether trash the work of Grail Bio and other players in this field. In many occasions, the criticism shifts from “MCED has too many false positives” towards the argument “we wouldn’t know how to treat them even if we found cancer early”.
In the US, even though five cancers have a screening procedure, including prostate, still 600,000 people die due to cancer every year, and mostly because the lack of screening for the cancers that people die from. Waiting 12 to 15 years, is 600,000 more deaths per year, every year, cumulatively, or 7.2 million deaths in 12 years time.
Delfi updates
Delfi Diagnostics reported on the applicability of their FirstLook LQ lung cancer screening test in ovarian cancer at AACR.
FirstLook uses cfDNA WGS to detect patterns of fragmented DNA (the length of the cfDNA molecules in the bloodstream) that are associated with the presence of cancer cells. Delfi’s FirstLook was out in October 2023 for people at elevated risk for lung cancer as long as they are eligible for screening.
FirstLook lung cancer test has now been validated in a prospective study in close to a thousand patients between patients and controls, Now the company will focus on ovarian cancer, where there is a significant unmet need for early detection methods.
In their ovarian cancer work, they analyzed blood samples from nearly 600 women with ovarian cancer, benign lesions, or without any known ovarian lesions who had been screened at hospitals in the Netherlands or Denmark. Cross-validation ranged from 72 percent for stage I disease to 100 percent for stage IV. This Delfi-pro test would then have a PPV of 16 percent, compared to 5 percent or lower for CA125 alone.
Other companies
Chinese firm, SeekIn reported on the results of their MCED test in a study of nearly 10,000 participants, The test is protein-based, utilizing a pre-defined panel of seven protein tumor markers — AFP, CA125, CA15-3, CA19-9, CA72-4, CEA, and CYFRA 21-1 — assayed using standard immunoassay technology plus clinical information like sex and age.
Overall sensitivity was 51.7 percent with a specificity of 93 percent, consistently even when using assays run on three different platforms (Roche, Luminex, and ELISA).
Cambridge, UK-based ProteoType, presented on a method that profiles the immune response to disease development by detecting the changing ratio of immunoglobulins and albumin, as well as class-switching among immunoglobulins, by measuring the overall concentration of amino acid residues incorporated into proteins in patient plasma. In internal data, they showed detection of 84 percent of cancers in a 92-patient cohort with a less than 1 percent false positive rate.
Finally, Chinese company Geneseeq showed data for a case-control assay development and some early results from its ongoing prospective validation of its CanScan test, which also analyzes patterns of DNA fragmentation. The assay achieved 87 percent sensitivity and 98 percent specificity.