Characterizing cancerous tumors is a very important step in personalizing treatments. Traditional tissue biopsies have been extremely invasive for patients and can lead to unintended side effects. But liquid biopsies -- which detect and analyze fragments of a tumor's DNA circulating through the bloodstream -- could be a much more effective and less expensive way to catch cancer at its earliest stages. Liquid biopsies have several technical challenges still to overcome, but they could unlock a $150 billion market for preventative cancer screening.

In the following video, Industry Focus: Healthcare host Shannon Jones and Motley Fool contributor Simon Erickson describe what liquid biopsies are and the opportunity they could offer to personalized healthcare.

A full transcript follows the video.

This video was recorded on Oct. 22, 2018.

Shannon Jones: You talked about biopsy. For most cancers, biopsy is how you diagnose a cancer. That's extremely invasive. What we have here is this shift. What we're really diving into is, can we actually detect within a blood sample this free-floating DNA? And, can we then use that to tailor or personalize the treatment options? Of course, there's also the aspect of early prevention, early detection, as well. But really, looking at it from a treatments-specific, personalized medicine approach.

There's huge advantages with not only capturing all this data, which was led by the Human Genome Project that started decades ago. Now, we're actually starting to see the fruit of that. Also, as you look further down the line, it's, how can we now take that and use those insights into actionable treatment plans that actually make a difference? And, to your point, Simon to do it early on, because that's where it makes a difference?

Simon Erickson: Absolutely. Liquid biopsies, like you say, so much less invasive than a tissue biopsy. This is a huge step for the medical community. It has its challenges, but that's definitely the direction I think we want to go with this.

Jones: Absolutely. This is a huge market. I was looking at some numbers, Simon. I saw upwards of $150 billion across the entire spectrum. Do you think that's outrageous at all?

Erickson: It's going to take time. It's not outrageous in any form. Like you said, this is a reactive vs. proactive approach that will determine the ultimate addressable market for these screenings. Again, right now, the addressable market is mostly later-stage cancers, patients that are showing symptoms. Maybe you're at Stage III or Stage IV. You just want to identify what cancer it is that's appeared. That might be less than a $10 billion market right now. Not so large. If we can push that back, like you said, with the liquid biopsy, a preventative screen through a blood test, there are estimates that even just in Stage II, that's a $40 billion market right there. Stage I would be more than $100 billion market. You add all those up together.

It depends how good we get at doing these screens. There's still a lot of challenges we have, not only financially, from a reimbursement perspective, of whether or not they're medically necessary for patients or just nice to have, nice to know. At this point, that's still unclear. And then, the other thing is the technical challenges, too. The last thing you want to do is have false positives where you're starting to really worry emotionally about having a cancer that's not actually there in the first place. Anything less than 100% or very near to 100% accuracy is going to cause a lot of issues.

This is a field that's still developing. Still has a lot of work to go, but definitely could be a $150 billion market. No doubt my mind.

Jones: Another thing to watch here is, as these companies start to develop these products, and we actually see them in these large patient populations, is looking to see just how congruent are these tests? Do they represent and show the same thing? There was some research a little bit earlier this year that seemed to put a question mark on that. I think there'll be more to come. But I think that's also another huge area to watch. You mentioned on the reimbursement side. Will payers like Medicare pick these up? Even from a regulatory pathway. I know the FDA has become much more open to innovative, personalized treatments. We'll want to continue to see that, and hopefully will continue to spur the entire ecosystem that's involved, from diagnosis all the way to care.