Lack of evidence should be clearly shared with patients

Many readers of this news blog may want to listen to or read Dr. Gerald Chodak’s latest video blog on the Medscape Oncology web site.

Under the heading “Physicians ‘want to do the right thing’“, Dr. Chodak argues (with his accustomed passion) that this also implies that “Lack of evidence should be shared with patients”. In other words, Dr. Chodak is saying that physicians need to clearly advise and inform their patients about the differences between guidance based on actual evidence (e.g., that drug X is better than drug Y in the treatment of metastatic, castration-resistant prostate cancer) and guidance based on opinion unsupported by reliable evidence (e.g,, that radiation therapy of type A is better than radiation therapy of type B in the treatment of locally advanced prostate cancer).

We would certainly agree with Dr. Chodak (and the data he cites from an article by Prasad et al. published earlier this year in Mayo Clinic Proceedings) that many recommendations made to patients are actually countermanded by data from well-structured, randomized clinical trials — when such trials get carried out. Regrettably, all too often, for one reason or another, the needed trials do not get carried out. In such cases patients need to be told with absolute clarity that the recommendation being provided is an opinion and is not supported by good scientific evidence. (Even the most recent AUA recommendations on screening for prostate cancer would appear to be a case in point.)

Of course the other point made by Dr. Chodak is that it is long past time that some really critical clinical trials (in prostate cancer in particular) needed to get done … and those needs are still outstanding.

One Response


    One of the examples of reversals is the PLCO study, in fact the original 2009 version of the study, that found no benefit of screening for prostate cancer. As readers and participants of this site are well aware, that paper was critically premature, with grossly inadequate time for follow-up that would be sufficient to observe a meaningful result. There were also other serious flaws that made any conclusion about the value of screening impossible to observe.

    In his video, Dr. Chodak talks about the need for “randomized studies that we can trust.” Clearly, indisputably, the PLCO study about the value of screening for prostate cancer, at least at this point, is not one of those studies.

    That gives me serious doubts about the rigor of the source paper by Prasad, Vandross, Toomey and others. I hope to have time to check the point about the value of vitamin D and calcium.

    However, I’m glad Dr. Chodak highlighted this new paper, and at least it gives us leads regarding challenges to accepted practices regarding our own personal medical issues. I’m going to pursue some of those.

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