Cancer Blood Test

As this linked article indicates, there is much excitement in the cancer community about a (fairly) new blood test that can detect cancer cells in a patient's blood. It's been around for a couple of years, but it recently got the backing of Johnson and Johnson, which will give it a pretty long reach, and an agreement to be tested out at Dana Farber, Mass. General, Sloan-Kettering, and MD Anderson (which is a pretty kick-ass group of four cancer hospitals). So there is a lot of promise and hope here (though, for me, some lingering skepticism....).

The test is sensitive enough to detect a single cancer cell among one billion cells in a sample of blood. The purpose, it seems, is not to find out if someone has cancer, but rather to determine if a cancer patient's tumor has begun to spread, by way of the bloodstream. The article has a description of how the test works; the blood sample is spread across a chip that is coated with antibodies; any cancer cells attach to the antibodies, where they can be counted. Very cool concept, and one of the success stories related to the Stand Up 2 Cancer program that has tried to encourage innovative, interdisciplinary approaches to solving cancer-related problems (the four hospitals above will be testing the test as part of a SU2C grant).

The blood test could also be used for patients who are undergoing treatment. Instead of a radiation-heavy scan, or an invasive biopsy, this blood test can give doctors some sense of how well a treatment is working. This is actually being done already, allowing doctors to see if the number of cancer cells in the blood is being reduced.

The article says that the blood test holds promise for certain cancers (breast, prostate, colon, and lung), but makes no mention of lymphoma. I'm not sure how this would work for "liquid" cancers like lymphoma or leukemia, though I could see that the use of antibodies, so common now in lymphoma treatments, could complicate things in some way. Not sure -- something to throw out to the support group, maybe.

I'm still a little skeptical, though. I guess it immediately had me thinking about the "full body scans" that became popular a few years ago, where people would pay for a CT scan that would reveal anything "abnormal." That had all kinds of problems -- unnecessary radiation, false positives, not to mention high costs. Maybe it's the potential false positives that bother me about the test -- I wouldn't want this simple to test to be used for purposes that are much broader than what is described here, like having some company promise that it could detect cancer early. That could potentially lead to lots of unnecessary worries and unnecessary biospies and scans for otherwise healthy people. But I suppose the tests have to look for particular types of cancer, given that they use antibodies as detection devices, so it would be pretty hard to test for every kind of cancer. At least for now.

So enough of that negativity. 2011 is the year of hope, right? We're just going to assume that this will work, and will be used for the right reasons, and we'll be hopeful that it will be expanded for use on lymphoma patients very soon.