Archive for the ‘Science’ Category

I abhor the pinkification of our culture.


I have nothing against the color pink (for a brief time in my childhood, after wearing a princess-like peach bridesmaid dress at my aunt’s wedding, peach was actually my favorite color), but I do have a deep dislike of the culture of cancer that has grabbed pink ribbons (or pink cookware, clothes, and even garbage barrels) to raise awareness *cough* money *cough* for foundations that make a big deal out of breast cancer.


I don’t want to downplay breast cancer.  According to The American Cancer Society, breast cancer is the most common cancer among American Women after skin cancer.  It is estimated that around 40,000 women will die from breast cancer this year.  But breast cancer awareness is also a BIG money maker- turning over many million dollars per year.


I’ve yet to see this movie, but the trailer raises some interesting points.



All the pinkification and fanfare would be tolerable if the breast cancer awareness campaigning, and most importantly the mammography that it promotes, reduced the toll of breast cancer, but the reality, according to a November 2012 New England Journal of Medicine article [1], is not such a pretty picture.


Let’s cover some of the basics…


To be an effective screening tool, a modality must detect life-threatening disease at an early treatable stage.  It follows that an effective screening tool then decreases the prevalence of late stage disease.


While screening mammograms have certainly led to an increased detection of breast lesions (it has effectively doubled the rate of diagnosis), the reality is that this increase in detection has not led to a significant decrease in advanced disease.  [The NEJM abstract is here, and certainly worth a read]. Furthermore, it appears that increased detection has had, at best, only a small effect on the rate of death from breast cancer.


What the NEJM of article doesn’t cover is the psychological toll that the pinkification of our culture has had.  Women feel like they are failing themselves if they don’t start getting annual mammograms at the age of 40.  Teenage girls are being brought up to believe that their breasts are two pre-cancerous lesions… ticking time bombs.


Yes- breast cancer kills, but there are also plenty of breast lesions that women have that they would live and die with, not from, if it weren’t for aggressive screening recommendations.  I’m not a psychiatrist (and I’m not going to be), but I do wonder what the increased diagnosis (and then “survival”) of otherwise slow-growing and relatively benign cancers does to the psyche – the survivor effect.  These factors raise a number of concerns, without even bringing up any monetary issues…


Apparently the prostate cancer ribbon is blue, but men (and our culture) seem to have avoided a tidal wave of “bluification”.  Perhaps, as the gender that tends to utilize the healthcare system less, [2], men have been seen as a less lucrative target. Nonetheless, prostate cancer has fallen victim to some of the same pitfalls (abuses?) as breast cancer.


Prostate cancer is the most common non-skin malignancy and the second leading cause of cancer death in men. Prostate specific antigen [PSA] is a protein that can be detected in the blood, and until fairly recently it had been recommended that men undergo regular PSA testing as a screening for prostate malignancy.


The problem with PSA testing however, much like mammography, is that it catches many lesions that a man would die with, not from.  As with mammography, increased detection leads to increased treatment, increased surgery, increased patient stress, and increased financial burden for the patient and the system. And for what?


Many of the lesions that PSA screening catches do not negatively impact the life expectancy of the patient.  In fact, a paper published yesterday in the Annals of Internal Medicine [3] shows the opposite- that treating these lesions (instead of observing them), actually leads to a decrease in quality-adjusted life expectancy (and increased medical costs).


What does this all mean?  Should we give up on screening tests for the two big sex-specific cancers?


No- I’m not a nihilist when it comes to screening, but I do think that screening should be done with full patient awareness of the risks, benefits, and consequences.


I think the American Urological Association (AUA) is on the right track, with their 2013 guidelines that greatly limit the recommendations for PSA testing (these came after the 2012 US Preventative Taskforce recommendations, which advised against the use of all PSA screening). While the AUA made general recommendations for some populations that PSA screening is unnecessary (those with a low-risk who are young, those who are old, and those with less than a 10-15 year life expectancy), for a large group the recommendation is that men should talk to their doctors about the relative risks and benefits, and from that discussion make a decision based on their personal values and preferences.


Having a patient weigh in with his personal values doesn’t seem like a particularly groundbreaking recommendation, but in many ways it is.  A patient’s medical care should be in his hands as much as possible, and when the risks and benefits of a screening tool are unclear it is appropriate that the patient and doctor discuss the risks and benefits.  Looking back at the data on mammography over the last few years, I think it is only right that doctors start to have similar discussions with women about their personal values and preferences when it comes to mammography. [The elephant in the room, however, is that if screening tests are deemed “optional”, will insurance companies cover them?]


So where does that leave us.   


Screening MAY catch an early cancer, but it may also catch a lesion that you would die with not from.  It can lead to extensive testing, stress, expenses, and surgery.  I’m not saying we shouldn’t screen, but I’m saying that the medical community (and the organizations that profit from cancer-awareness) need to be honest about the reality of our testing modalities.


I also think this is a call to arms for scientists.  The screening tests we have are not meeting our needs.  While the tests above can tell us about potential lesions, they tell us little about the malignancy of the lesions.  We need tests that can more accurately tell us what is going on in our bodies.  Those tests are coming- in the forms of mRNA and protein assays, but until they get here I think we ought to have more informed discussions about what screening tests are really doing today.


1.            Bleyer, A. and H.G. Welch, Effect of three decades of screening mammography on breast-cancer incidence. N Engl J Med, 2012. 367(21): p. 1998-2005.

2.            Bertakis, K.D., R. Azari, L.J. Helms, E.J. Callahan, and J.A. Robbins, Gender differences in the utilization of health care services. J Fam Pract, 2000. 49(2): p. 147-52.

3.            Hayes, J.A., D.A. Ollendorf, S.D. Pearson, M.J. Barry, P.W. Kantoff, P.A. Lee, and P.M. McMahon, Observation Versus Initial Tretment for Men with Localized, Low-Risk Prostate Cancer: A Cost-effectiveness analysis. Annals of Internal Medicine, 2013. 158(12): p. 853-860.

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Abstract dangers

Scientific journals aren’t for everyone. Journal articles use technical writing and can be rather dry. They can be long, they can be dull, they can show nothing new and exciting, or the research they describe can be so poorly thought out you wonder how a reviewer ever allowed the paper to go to the presses. Many good article are behind pay walls, so even if you want to read them, sometimes you can’t.


Fortunately an abstract of most papers can be found for free.  An abstract is a brief summation drawn up by the authors to get their point across.  Maybe it’s just me, but I sometimes think that abstracts can be a bit like movie trailers- they introduce the major players and they give you a general plot of the movie (and they try and hook you in by showing you all the good scenes).


Like a movie trailer, abstracts can be deceiving.  Take the trailer for The Matrix Reloaded– how excited were you when you first saw that trailer? How much did you wish the movie had never been made after you saw the actual feature?


Unfortunately, while in the cinematic world people are unlikely to act like they’ve seen the whole movie when all they’ve done is watch a trailer, in the world of scientific literature it often seems that people assume that reading the abstract is as good as reading the paper.


It is not.


The list of examples is endless, but this morning I stumbled across an example of this that finally pushed me to write about abstract abstraction.


It all started when I saw a tweet proclaiming “A high saturated fat mixed meal induces inflammation & insulin resistance & elevated glucose cf [compared to] other types of fats”.  Considering my interest in fats and my particular fondness for saturated fats you may not be surprised to hear that I decided to dig a little deeper.


The paper is from an open access journal. The full text is available here.


To be fair, the title of the paper is not quite as sensational as the tweet that led to it- The effect of two iso-caloric meals containing equal amounts of fats with a different fat composition on the inflammatory and metabolic markers in apparently healthy volunteers– but the “conclusions” offered in the abstract (the line that anyone who is just skimming the article will jump to) is rather dubious:


Metabolic and modest inflammatory changes occur within a few hours after the ingestion of a high SFA meal in apparently healthy adults.


I don’t have the time or the inclination to totally dismantle this paper (I really wonder how they did their statistics to show there was a significant difference), but I do want to point out how unwise it can be to draw conclusions from this abstract.


Let’s compare the methods sections. In the abstract, the authors say that healthy participants “were given two iso-caloric meals with similar amounts but different composition of fats: a meal high in monounsaturated fats (MUFA), and a meal high in saturated fat (SFA).”


The methods section in the paper reveals more detail:


The chosen meals represented two very popular meals habitually preferred by the general population: 1. Chicken sausages with fried potatoes, ketchup and mayonnaise (defined as SFA); 2. Pasta with olive oil, ketchup and nuts (defined as MUFA).




Two entirely different meals, and we’re supposed to believe that any differences in blood markers (of which I am skeptical) are due to the change in the type of fat- fat types that aren’t particularly well represented in at least one of the meals.  Chicken is not high in saturated fat.  Chicken fat is predominantly unsaturated, a combination of MUFA and polyunsaturated fats (PUFA), with less than a third of chicken fat being saturated.  What were the potatoes fried in? These days most things are fried in PUFA rich vegetable oils not SFA rich animal fats or coconut oil.  And mayonnaise? Mayonnaise contains very little saturated fat (because it’s usually made with PUFA-rich vegetable oils).  At least the second diet utilizes olive oil, which is rich in MUFA.


The authors state that they used the Israeli Food Database to calculate the breakdown of SFA:MUFA:PUFA in each diet and that the “SFA” and “MUFA” diets contained 24:33:17g and 8:51:14g respectively. Without knowing more about the ingredients (what fats and oils were used in the SFA diet and what nuts were used in the MUFA diet) it’s hard to know if the breakdown is accurate.  The meals are so different in every regard, it’s silly to quibble over the exact proportion of each fatty acid type.


The point of this post isn’t (or wasn’t) to pick this paper apart.  The purpose was to show that we should be cautious when drawing conclusions from abstracts.


The authors chose to say that any changes (that may or may not be real) occurred after “the ingestion of a high SFA meal”, but they could equally have said “after the consumption of mayonnaise (or potatoes)”… Likewise, they could have claimed that pasta (or nuts) “protects against metabolic changes induced by ketchup”. Of course, all of these claims would be ridiculous- though perhaps less ridiculous than suggesting any changes were due to ingestion of a high SFA meal (something they didn’t even test)!


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