The news release highlights this recent study of a commercially unavailable blood test to detect ovarian cancer. The study is quite small and explores whether the test detects cancer in women already known to have it. The results are too preliminary to conclude whether or not this experimental method could reliably detect cancer in large numbers of women whose cancer status is unknown.
This is key information for readers and should have been made much more clear.
The news release does well in establishing the scope and diagnostic challenges of ovarian cancer, but falls quite short in letting readers know that most of the authors — two of whom offer quite optimistic quotes — are inventors of the test with pending patents.
Ovarian cancer is common and often fatal. Symptoms often develop late, when the cancer is advanced and much more difficult to treat. Technologies that might facilitate earlier diagnosis could have a much needed impact on disease stage and rates of death.
Anyone writing news releases about such early detection methods should place a premium on caution and clearly address: How preliminary are the results? What limitations should readers be aware of? What are the chances of both falsely positive tests (finding cancer when it isn’t there) and falsely negative tests (not detecting cancer when it IS there).
Finally, as this news release illustrates, do the researchers strongly promote the tests, even though their results are quite preliminary, and their financial conflicts of interest quite significant?
Cost is not mentioned and, according to the published study, the high costs of the sensors used in detecting the cancer have proven to be a major drawback.
The only benefit mentioned is this:
“the new test detected significant levels of the cancer glycan in blood samples from over 90% of women with stage 1 ovarian cancer, and in 100% of samples from later stages of the disease, but not in any of the samples from healthy controls.”
We’re glad to see it made clear that the blood test was increasingly positive for cancer in those women already known to have increasingly advanced cancer.
However, it should have been made even more clear the overall study group is quite small (69 women), with only 23 women having known stage I/II disease; therefore, this study can not show if the blood test would be effective as a screening tool in healthy women.
It’s very important to show how the test looks in populations with and without cancer — which will likely be done in the future. The public needs to know and be clear about that when a person has cancer, the test is positive and if we know there is no cancer the test is negative.
As is so often the case with news releases about cancer screening tests, what usually gets highlighted is the sensitivity; in this case, that early stage cancers resulted in a positive test 90% of the time.
But what’s not highlighted — and can cause significant emotional harm — is that 10% of the time the test will be negative in someone who has cancer. That “false-negative” result provides false reassurance that there’s no cancer present. In addition, there may be a small number of “false-positive” tests leading to inappropriate procedures. Readers need to know how often false positive results occur with the test, and that’s something a small study such as this can’t confidently address.
As mentioned above, this is a relatively small study that could only show that the screening test worked most of the time in women already known to have ovarian cancer.
Its effectiveness as a screening method for the general population can not be determined from this study.
Therefore it’s premature to state this blood test “has the potential to dramatically improve early detection of the disease … a potential game changer.” These preliminary data do NOT support such claims.
No disease mongering here. The scope and diagnostic challenges of ovarian cancer are appropriately included.
A major weakness of this news release is failing to mention that four out of six of the authors are “named inventors on a patent” related to this screening test.
Also, the funding for this study is not included.
No other alternative tests are mentioned. Cancer antigen 125, or CA-125, a test for screening for ovarian cancer, is recommended when there is high clinical suspicion (when the patient is having particular symptoms to suggest the presence of cancer).
Mentioning this test, and its pros and cons, would have provided useful context for readers wondering about how these preliminary results stack up against our current screening tests.
The release should also have noted that the US Preventive Services Task Force recommends against screening for ovarian cancer in asymptomatic women. The American College of Obstetricians and Gynecologists does not support screening.
Here’s the last sentence of this very brief news release:
“The [research] team is currently seeking scientific and commercial partners to further test the technology with larger numbers of patient samples and to adapt it for mass screening.”
It doesn’t completely clarify for readers whether the test is currently available, but suggests it isn’t.
It’s stated that the bacterial toxin used in the test was “discovered” by the Adelaide researchers, and that this is a “new blood test.”
As noted above, there is some unjustified language used; especially given the preliminary nature of these findings.
Most distressing is that a lead author — who stands to benefit from a pending patent related to the blood test — claims “our new test is a potential game changer.”
Likewise, reference to adapting this technology “for mass screening” is rather premature given this study does not address the specificity/sensitivity of this blood test in screening a large population whose cancer status is unknown.
(Remember: mass screening implies being able to reliably find cancer in people without symptoms.)