3 ms·

Liquid biopsy is an exciting field but to call the current results “promising” seems like a stretch to me. The entire point of doing screening is catching early

Liquid biopsy is an exciting field but to call the current results “promising” seems like a stretch to me. The entire point of doing screening is catching early stage cancers. For these cancers, liquid biopsies miss far more than imaging in every study I’ve seen (even early non peer reviewed results). For this reason there is as of yet no evidence that drawing a blood sample can be a first step before imaging for the high risk populations where screening is done today. You still need to do imaging for those. However, it seems like an interesting avenue for increasing the size of the screening population but then false positives become a serious problem within a low risk population.

sjg007 8y ago
This is definitely a get all of the data and see what sticks type of analysis. There should be some early evidence from a smaller sample set using cluster analysis that is suggestive that mutations can be classified and are predictive. Tons of issues to resolve. I would think that some biostatisticians should be able estimate the false positive rate from a theoretical basis.
- dontreact 8y ago
  My point is that there have already been a lot of results showing liquid biopsy misses a lot of the cancers in high risk populations. At this point theoretical estimates seem inferior as evidence than what we know so far from actually measuring. At some point in the future we may understand more about what markers to look for in the blood and this may change but as of yet there are no "promising" results. Maybe I'm nitpicking but the concept of liquid biopsy is exciting and I hope it's something that humanity figures out how to do!
  - sjg007 8y ago
    Do you have a reference I could check out? My point was this is looking at sequencing all of the cell free DNA and seeing post hoc if any of that data is predictive of some cancer developing. There are a wide number of issues taking that approach including it not being viable at all. Still it is an interesting data set. And as you state there are other biomarkers that may be more useful that still fall under the category of a liquid biopsy.. what we really mean here is something non-invasive like a blood draw. I was interested in the FP rate theoretically just cause it would be interesting to understanding the screening watchful waiting type approach vs what we have now.
    - dontreact 8y ago
      43% of Stage I cancers detected, 33% of breast cancers detected and called "the best result so far" by this one science blogger (for breast imaging these numbers are usually around 90): https://blogs.sciencemag.org/pipeline/archives/2018/01/22/a-hard-look-at-liquid-biopsies https://blogs.sciencemag.org/pipeline/archives/2018/01/22/a-...

sjg007 8y ago

This is definitely a get all of the data and see what sticks type of analysis. There should be some early evidence from a smaller sample set using cluster analysis that is suggestive that mutations can be classified and are predictive. Tons of issues to resolve. I would think that some biostatisticians should be able estimate the false positive rate from a theoretical basis.

dontreact 8y ago
My point is that there have already been a lot of results showing liquid biopsy misses a lot of the cancers in high risk populations. At this point theoretical estimates seem inferior as evidence than what we know so far from actually measuring. At some point in the future we may understand more about what markers to look for in the blood and this may change but as of yet there are no "promising" results. Maybe I'm nitpicking but the concept of liquid biopsy is exciting and I hope it's something that humanity figures out how to do!
- sjg007 8y ago
  Do you have a reference I could check out? My point was this is looking at sequencing all of the cell free DNA and seeing post hoc if any of that data is predictive of some cancer developing. There are a wide number of issues taking that approach including it not being viable at all. Still it is an interesting data set. And as you state there are other biomarkers that may be more useful that still fall under the category of a liquid biopsy.. what we really mean here is something non-invasive like a blood draw. I was interested in the FP rate theoretically just cause it would be interesting to understanding the screening watchful waiting type approach vs what we have now.
  - dontreact 8y ago
    43% of Stage I cancers detected, 33% of breast cancers detected and called "the best result so far" by this one science blogger (for breast imaging these numbers are usually around 90): https://blogs.sciencemag.org/pipeline/archives/2018/01/22/a-hard-look-at-liquid-biopsies https://blogs.sciencemag.org/pipeline/archives/2018/01/22/a-...