Mammograms and a “history of breast cancer”
I was talking about my previous post (http://wp.me/p4e7xm-1H) with a colleague. We were discussing how the cautions against regular mammograms probably do not hold for individuals with a family history of breast cancer. My colleague then pointed out that in fact women’s histories have been contaminated by the high number of women “successfully” treated for tumors that would likely have gone away on their own. This means that for a whole group of people with relatives whose tumors were successfully treated, it is unclear whether they truly have a family history of breast cancer or not.
Let me explain. Remember that cancer cells compete with other cells for the body’s resources. When cancer cells “win”, the tumor grows and grows and ultimately can kill. When cancer cells lose, they shrink away and don’t impact health. Mammograms don’t distinguish between the tumors that are destined to be winners and those destined to be losers. Now consider that mammograms have been in increasingly common usage since the mid 1970s. Consequently, many young women have mothers, aunts, and cousins who have had “positive” mammograms. Customarily, tumors discovered by mammograms have been treated – typically by surgical removal – and in many happy instances, no recurrence occurred. In these happy instances, there is indisputably a family history of a relative treated for breast cancer. However, the treatment may or may not be the reason that no recurrence occurred. So do the female relatives have a family history of breast cancer or not?
My graduate advisor taught me the phrase: “true-true-unrelated”, which is shorthand for saying that Truth A and Truth B are both true but that Truth A did not cause Truth B and Truth B did not cause Truth A. [ I have always liked true-true-unrelated as a pithy way to say that no causal relationship exists.] In the absence of a causal relationship between treatment and survival without recurrence, it is not clear whether women whose relatives have successfully been treated for breast cancer do indeed have a history that would warrant regular mammogram screening.
Similar concerns exist for other cancers including prostate cancer. My understanding is that many men, including young men, have cells that exist somewhere on the continuum toward malignant prostatic cancer and that the vast majority of these should not be treated as they are bound for defeat anyway (and in fact are not treated). While the cancers and tests differ, the psychology is similar. In order for an individual to choose not to treat “cancerous cells”, that person has to beat a deeply held belief that all cancer is bad. And we know that facts are typically insufficient for this job. Maybe facts that include an understandable framework could do the trick.
Finally, for those of you who are wondering about the picture above, it is has nothing to do with this blog post. But it is a pretty picture of the Eiffel Tower and I am in Paris right now.