Last week we reported data from a study by Tangen et al. suggesting that men diagnosed with metastatic prostate cancer are living longer today than they were in the 1980s and early 1990s. Frankly, we don’t find this finding particularly surprising. Why this is happening is a whole different issue.
According to a commentary on Reuters.com, published last Friday, Dr. Brawley (the Chief Medical Officer of the American Cancer Society) appears to have gone out of his way to suggest not only that we cannot attribute this increase in survival exclusively to the application of PSA testing (which we entirely agree with, and which was clearly stated by the authors of the paper) but also to imply that this survival benefit may not even be real (which we find to be an extraordinary suggestion).
Now, to be fair to Dr. Brawley, it is not entirely clear exactly what he did or did not say when interviewed by Reuters. Only some of what he supposedly said is actually placed in quotation marks and therefore should be assumed to be what he actually stated.
In some places he is very clear that you cannot attribute this survival benefit to PSA testing alone and appears to be suggesting that there may be other good reasons for the survival benefit. This is a precise quote from Dr. Brawley as reported by Reuters:
You cannot say that PSA testing is the cause for this improvement, but when you eliminate all the other potential explanations there is something else there that is playing a role.
However, Dr. Brawley also seems to have indicated that data from the management of other cancers would suggest that the perceived survival benefit is questionable for any reason. The following information from the Reuters commentary includes a direct quotation from Dr. Brawley, but was not all actually stated by him verbatim:
… other trials done by the same research group but involving non-Hodgkin lymphoma, a group of blood cancers, also show patients live longer over time, according to Dr. Otis Brawley. … And that’s despite the facts that doctors don’t screen for the disease and that patients got the same treatment for their disease. … “There is a cohort effect that we have seen numerous times in medicine,” said Brawley, …. He added that the reasons for the improved survival over time are unclear, but could be related to advances in medical care and infection control.
Of course medical care and infection control have improved over the past 30 years. Thank goodness for that! In addition, it is reasonable to consider that we do in fact monitor people for risk of blood cancers like non-Hodgkin’s lymphoma (a group of several related types of blood cancer). Risk for non-Hodgkin’s lymphoma can be identified by swollen glands in the neck, armpit, and groin, by the presence infections (particularly of certain specific types of infection), and by the presence of excessive numbers of white blood cells in your blood. Thus, anyone who gets a regular annual check up is being monitored for the possible risk of lymphoma. Do we have a test to screen specifically for non-Hodgkin’s lymphoma? No we don’t. And we don’t have a test to screen specifically for prostate cancer either, because the PSA test is not cancer-specific.
Dr. Brawley has long expressed a strong personal belief that widespread use of the PSA test (i.e., mass, population-based “screening”) is not associated with any significant survival benefit in the management of prostate cancer. Others agree with him about this. However, unless Reuters has misinterpreted Dr. Brawley’s remarks, he is now at least hinting that any appearance that men diagnosed with metastatic disease may be living longer today than they did 30 or so years ago may also be “bunk”.
What the authors of the original paper were very, very careful to note was that while this increase in the survival benefit of men diagnosed with metastatic disease occurred during the “PSA era” it was not possible to know exactly why it had occurred.
Dr. Ian Thompson, the senior author of the current study and the current co-chair of the prostate cancer committee of the Southwest Oncology Group (SWOG), apparently told Reuters that,
I guess I have a difficult time explaining the difference [in survival].
Dr. Thompson is a highly regarded and careful scientific investigator who is also well known for his care and tact in his public remarks to the media. His comment is entirely in line with the conclusions of the original paper. He is correct. Explaining in detail why this survival benefit is occurring is extraordinarily difficult and may well involve a multitude of factors (inclusive of the advent of PSA testing). However, Dr. Thompson appears to have made no suggestion that this survival benefit is not “real.”
What The “New” Prostate Cancer InfoLink would like to understand is whether Dr. Brawley’s remarks reflect the official opinion of the American Cancer Society — which he presumably represents, as its Chief Medical Officer — or his personal opinions, which are most certainly at least “colored” by his views on PSA testing. Dr. Brawley is entirely at liberty to express his personal opinions (as are the rest of us). However, once again he seems to have failed to distinguish between those personal opinions and the official position of the American Cancer Society.