Wednesday, July 16, 2014

The mammogram benefit discussion

There have been a few (thousand) discussions on the benefits of regular mammograms in the past few years. There are all sorts of claims on the problems of false positives, over diagnosis, false negatives, and all that.

So stop the presses and read the results of this latest survey. Its a bit of a statistics lesson so allow me to break it down with my stellar liberal arts education and marketing background

This survey looked at the incidence of breast cancer and the increased diagnosis trend from 1941 on. The first half of the time studied was from 1941 to the 1970s before mammograms - the base data.* Then it looked at the rates of diagnosis from the 1970s to the present.

What they could tell from the base data is the trend in increase in breast cancer from increased environmental or whatever factors and got their base rate of increase of 1.3% annually - or the expected rate of increase in breast cancer diagnosis. They also got their percentages of expected diagnoses of early and late stage diagnosis.

Then they looked at the date from the 1970s to present. What they then determined is that since the introduction of mammograms, the proportion of diagnoses of early stage cancer are up significantly and there is a 30% decrease in the expected rates of late stage diagnosis.

That is the benefit of mammography. The 30% decrease in late stage diagnosis. If you wish to debate the benefits or lack of benefits of mammography, please figure out a way to dispute that point.

*My 1981 cancer resource book from my first thyroid cancer diagnosis does talk about how mammography was being considered for annual screening for all women.

1 comment:

Anonymous said...

Caroline, with all due respect, you shouldn't be fooled by the misinformation put out by proponents of screening mammo. The fact is, screening mammo has not reduced the incidence of metastatic breast cancer, and that is what really kills women. "Late stage" is a red herring. Since screening doesn't reduce the incidence of breast cancer that has spread, it can't work. Please see the following from dr. Gil Welsh:

According to Dr. Welch, we are seeing an excess of early-stage breast cancer diagnosis with only a small reduction in late-stage diagnosis. Troublingly, there has been no benefit in terms of decline in women who are diagnosed with metastatic breast cancer.
- See more at: http://www.bcaction.org/2013/12/11/sabcs-2013-screening-mammography-and-overdiagnosis/#sthash.opG6isTu.dpuf