There are 429 words in this news release. Nearly half are contained in just two exuberant quotes from Stanford researchers. If the study itself backed up the claims made in these quotes, we would applaud the release for its economy of language.
As it stands, the release needed much more information to help journalists and other readers understand that this is a very limited study that may or may not turn into a true alternative to other cancer diagnostics.
The news release makes a huge claim with its headline: “New blood test may transform the way cancer is monitored and treated.” It then doesn’t provide any evidence to support this claim. It could just as well have declared “new blood test may not transform the way cancer is monitored and treated.”
We like that the cost issue is addressed. But the terms are vague. It says that the test is “relatively low cost.” Relative to what? To traditional “whole body imaging,” as the release notes above? Then provide some of those costs. It also says, “especially compared to next-generation DNA sequencing,” which costs how much?
We were expecting a thorough explanation and some numbers that illustrate how this test could more regularly track the growth and spread of cancer cells. But there was no quantification in the release.
There is no mention of harms. The assumption here is that more regular monitoring of patients via blood samples will lead to better outcomes, when we actually know from repeated studies that more monitoring for disorders leads to more unnecessary treatments and surgeries.
What is the false positive rate? The false negative rate? What are the possible clinical harms that can result from either of these scenarios?
The release does explain, after a very effusive quote about how broadly applicable this test may be, that the test was only examined in six patients who had only two types of cancers. Then it says, “the researchers were able to identify tumor-derived circulating DNA from three out of six patients.” So the study was extremely limited in scope. The release would have been better to call out this caveat explicitly instead of leaving it up to the reader to figure out. Other releases we have seen say things like, “This study was only conducted in six patients and would need to be repeated with a much larger group in order to make strong claims about its broad efficacy in cancer diagnosis and monitoring.”
There is no disease mongering in the release.
Funders are noted in the sidebar where this release is hosted on EurekAlert! but not in the release itself. We encourage news release writers to include funders in the body of the release. There is no mention of conflicts of interest in the release, nor in the study itself.
The release makes a glancing reference to “other methods.” It says, “The single-color digital PCR test offers several advantages over other methods of circulating tumor DNA analysis, compared to next-generation targeted sequencing and fluorescent probe-based digital PCR assays. The main advantage is that the new technique does not rely on pre-amplification, which can introduce errors and biases.” This is not an adequate comparison.
It would have been helpful to mention specific blood tests for the tumor types looked at even in this small sample size–this would have given context and why this work is important.
It is clear from the release that the test is not widely available and is only just now being developed.
The release establishes novelty here:
The test, which is called single color digital PCR, requires only a fraction of a tube of blood and can detect as few as three mutation-bearing molecules in a single reaction.
We think that given the extremely small number of patients who even had test results that could be monitored for cancer growth — three people! — making broad claims about this being a low-cost alternative for all cancers is over the top. This is what the release says:
“For monitoring patient tumors, only a handful of blood tests are available which are limited to only several types of cancers. Nearly all cancer patients require monitoring by whole body imaging, which can be costly, complex, and time-consuming. In contrast, molecular tests like the one we have developed will enable patients to be monitored at every visit, and thus have the potential for quickly tracking cancer growth and spread.”
Does that sound like a test that was only used on six patients, only three of whom had detectable cancer?