How much more study do we require to understand that there are things which cannot be known? In the British Journal of Medicine (BJM link), a twenty five year follow up of the Canadian Breast Screening Study again failed to show any benefit in the screened group. Gina Kolata followed up with a NYT piece today (Kolata). I doubt this work will sway anyone. We have left the realm of a world settled by data and entered into the realm of medical partisanship where belief trumps everything.
I became aware of the work of Dan M. Kahan who recently published a working paper as part of the Cultural Cognition Projection. In the paper, he published the results of a clever experiment (Motivated Numeracy and Enlightened Self-Government) where he looked at conclusions drawn from simple data in 2 x 2 tables. The same exact data when linked to non-controversial scenarios (response of a rash to treatment with a cream) yielded completely different conclusions from individuals as opposed to when these data were associated with partisan questions regarding gun control. When strong beliefs entered into the equation, objective assessment of the data disappears.
Within the medical world, we have developed a host of partisan issues and we would be well served to
Much like the last time such an article was published in NYT, the letters displayed remarkable partisanship. For the true believers, particularly those in whom mammography found what was diagnosed as cancer, no contrary information will convince them that their lives were not saved. It may be that for a vanishing small group, their perception may represent the truth. The estimates are somewhere in the realm of 1-2 per thousand screened for 10 years may have their lives saved. It is worth it? It depends on how you look at the question, whether the resources spent were your own, and whether similar resources spent differently may have saved or enhanced more lives.
This does not need to be a controversy for a simple reason. Screening mammography is a relatively cheap tool. The roughly $100, which needs to be spent every two years, represents about two tanks of gasoline or a fraction of a family grocery bill for one week. If patients were required to pay for this out of pocket, would a well informed consumer, given all of the data we know, view it as a good investment of their own money? One can ultimately feel as strongly about this issue as you desire, and this can be translated into action through the allocation of your own resources. Something cannot be that important if you cannot convince a patient to allocate $100 once every two years.
My guess is if patients had to buy this product using their personal resources, it would be a tough sell, given how convincing the data is. There are some patients who will purchase just because the activity resonates with them. I am also sure that a shrewd marketing campaign might be successful in convincing at least some additional patients to partake, much in the same way that marketers cleverly use fear to sell or sorts of products, whether it be insurance, home security, or anything that can be dressed up as a solution to some sort of personal threat. Fear sells. However, there is a not so fine line where patient educational materials cross over into marketing materials, especially if the fear message is is heavy handed and not supported by data which shows your customers garner actual value from their investment.
There are literally millions of choices we can make relating to how we allocate our personal resources. How we make these decisions depends upon our own individual preferences and our individual resources. I think I am on safe ground to say that the case for screening mammography is not going to get any more conclusive and there is no good reason to try to force some sort of universal set of actions on the parties involved. My take on this and a host of other screening activities is many are a bad deal for me and for other patients. There are better ways for me to invest my time and money.
The mammography controversy screams out that current insurance system only makes this problem oodles worse. We need to figure out how to take whatever resources that now go to pay for these back in the hands of women who can decide if participation makes sense. If they elect to get screened, they are no worse off than they are now. If they elect not be screened, they can allocate those resources to something else they deem of greater value. Good and smart people will make a variety of decisions, not all of which all members of the medical community will agree with. Many women will continue to chose to be be screened. Many will not. It is not entirely clear what the best decision should be and we will likely never know that answer. One size does not fit all.