This is a story about a study for a test under development, the results of which suggest that it may be better able to predict which diagnosed prostate cancers are aggressive and which are not. This would be an exciting development as indicated by the spokesperson from the UK Prostate Charity. However – the story should have tempered its enthusiasm a bit until the results have been reproduced.
A better test would have fewer false positives and be less likely to detect clinically unimportant disease. In addition, it would be useful to remind readers that it is one thing to properly identify disease that is aggressive but more important to be able to identify aggressive disease still sufficiently early in its course that it can be treated before metastasis takes place.
Not applicable. There was no discussion of cost but since this test is investigational, information about pricing is not expected at this time.
Readers could extrapolate that if the MSMB test results are demonstrated to be reliable and reproducible, then it could be expected to reduce the number of men treated for prostate cancer who likely would never suffer ill effects from the disease. However it is appropriate to withhold some enthusiasm until the test’s performance is demonstrated to live up to its potential. And, true to what we expect in this criterion, the story never explained the sensitivity or specificity of the test in absolute numbers; it only used unhelpful general terms such as "found at significantly lower levels." How often? How reliably? All the time?
The story detailed the harms associated with the current means of testing for prostate cancer. While suggesting that the new MSMB test was able to distinguish between aggressive and non-aggressive prostate cancer, the story did not provide details about how well the test was able to do this. In a nutshell, the story mentioned (though it didn’t quantify) the high false positive rate associated with PSA, but it provided no detail on the relative false positive rate of MSMB. It also failed to mention whether the test failed to pick up on a percentage of prostate cancers that were present.
The real heart of the evidence was not clearly explained. It is difficult to interpret the comment that men with aggressive tumors are likely to have lower levels of MSMB protein in their urine. That may be true, but does it distinguish men with aggressive tumors from those with non-aggressive tumors? If a substantial proportion of men with less aggressive cancers also have low levels of the protein in the urine, then the test may not be that helpful in discriminating the two groups.
The story did engage in a bit of disease mongering with the number of men diagnosed world wide with the disease and reporting that prostate cancer was the second most common cancer cause of death among American men without indicating that in the U.S., the lifetime risk of dying from prostate cancer is 3% . Most problematic was the statement that "In Britain, around 35,000 men are diagnosed with it and some 10,000 die from the disease." But no time frame was given – no way to give such estimates.
The story included comments from two individuals involved with the study reported on as well as an individual with expertise in the field without links to that study.
The story indicated that the current laboratory screening test for prostate cancer (PSA) has low specificity and that because it doesn’t distinguish aggressive disease from that which is less aggressive, it leads to unnecessary treatment. The story was strongly suggestive that the test reported on had the potential to reduce both of these. But it didn’t offer any data-driven comparison – limited though that possibility may have been given the early stage of this research. But it also didn’t compare this test with other urine tests trying to do the same thing.
The story was clear that the MSMB test reported on is investigational and not currently available.
The story neglected to mention that there are other urine tests (PCA3 for example) that are already available. What’s the relative advantage/novelty of this urine test over those others?
The story would have been improved by indicating that the study reported on is among several that have indicated the utility of this protein for the purpose of diagnosing and predicting the aggressiveness of prostate cancer that have been published in the last couple of years.
Does not appear to rely solely on a news release