Read Original Story

Reuters adds some cold water to direct-to-consumer ‘liquid biopsy’


5 Star


Pathway launches 'liquid biopsy' to find cancer in healthy people

Our Review Summary

This story did a very nice job of examining the premise behind “liquid biopsies” and pointing out the lack of supporting evidence — a slightly more thorough look than was given by a strong competing story from Bloomberg. While the story could have had a fuller explanation of the costs associated with liquid biopsies and how the tests are ordered, it better explained the potential harms and made better use of independent sources to provide context than Bloomberg did.


Why This Matters

Genomic testing of healthy people is going to cost this country a lot of money, and the proposed benefits of such testing haven’t been proven at all.


Does the story adequately discuss the costs of the intervention?


The story mentioned the cost of the test, but the competing Bloomberg story gave a more detailed breakdown of costs. There was no mention of insurance coverage, or of total costs of work ups of positive tests and the need for continual testing.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


The story cites a company figure stating that the test “is more than 99 percent accurate in detecting mutations in blood samples that contain at least nine copies of a tested mutation.”

It then knocks down that figure with a quote from a researcher who says the statistic represents the test’s “technical ability to detect DNA in the blood.” It goes on to state that a large clinical trial would be needed to determine the test’s true accuracy, including false positive and false negative results. But such a study hasn’t yet been done.

Does the story adequately explain/quantify the harms of the intervention?


The competing Bloomberg story gave a nod to false positives and false negatives, but Reuters really explained why these tests could lead to harms. The story says, for example, “Patients might be attracted to a less-invasive test for colon cancer, but if it is less effective, it might result in more cases of colon cancer, not fewer. Another concern is that the tests may pick up on markers that are never destined to be cancer, something already known to occur in blood tests for prostate cancer”.

Does the story seem to grasp the quality of the evidence?


The story nicely explained the lack of evidence for this particular test.

Does the story commit disease-mongering?


There was no disease mongering in this story. Quite the opposite. It turned a light onto this growing industry and questioned whether tests of biomarkers would actually lead to better clinical outcomes.

Does the story use independent sources and identify conflicts of interest?


The story quoted more independent sources than the competing Bloomberg story, and it also did a good job of identifying where people had conflicts. For example, the last expert quoted says that the test should undergo a large clinical trial, a point of agreement among multiple experts quoted in the press. But then the story says that this expert, “is advising two companies developing liquid biopsy tests for cancer screening: Sysmex and Personal Genome Diagnostics.”

Does the story compare the new approach with existing alternatives?


The true alternative to these tests is routine cancer screening using proven screening methods recommended by the US Preventive Services Task Force. In fact, the whole name “liquid biopsies” is wrong. These are not biopsies at all, they are screening tests for healthy people that look for biomarkers of cancer in the blood. But we don’t know what kind of clinical significance they have or if they will lead to better outcomes. Neither story gave a full explanation of the alternative screening approaches, although this story did mention colonoscopies (which are one such screening method) as well as screening tests for prostate cancer. We’ll give the benefit of the doubt.

Does the story establish the availability of the treatment/test/product/procedure?


The story says that “The tests must be ordered by a doctor, based on a patient’s risk profile.” However, it’s not clear that this fully describes the process. While the tests can be ordered through the patient’s physician, the Pathway website also suggests that patients can order them autonomously online through Pathway’s “online physician network.” Here’s the text:

Patients can also order CancerIntercept™ Detect online through Pathway Genomics’ online physician network. After speaking with a client services representative, the patient must create a personal account with Pathway Genomics Member Site ( and enter all personal health information into the website for physician review. It will take up to 1-2 business days for physician review, at which time a sample collection kit will be sent to the patient’s provided shipping address if the test is approved.

This process seems essentially to be a direct consumer purchase with the involvement of an online physician middleman — something which is not fully conveyed by the text. We’ll give the benefit of the doubt since it’s debatable whether the story is technically wrong on this point or not. But we wish more detail had been provided.

Does the story establish the true novelty of the approach?


The story establishes what’s novel about the test compared with existing tests.

Does the story appear to rely solely or largely on a news release?


The story went beyond any news release that may have been issued.

Total Score: 10 of 10 Satisfactory


Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.