It seems like the more medicine seeks to try and make strict recommendations on what good screening policies to follow, the more confusing it gets. This time questions are being raised about the efficacy of mammograms.
Conventional wisdom had taught us that the best approach is for women to have a screening mammogram every year after 40. Now, we hear that maybe that approach needs to be changed or at the very least revisited.
A recent study published in the British Medical Journal indicates that there is no decrease in deaths from breast cancer as a result of yearly mammograms.
As you might imagine, that has really caused quite a bit of concern and confusion.
The study was started in 1980 and followed almost 80,000 women in Canada divided into 2 relatively equal groups. One group got the physical exam and mammograms, and the other received just the physical. The sheer numbers of patients in this study make it impossible to ignore. The question becomes though, What does the data that they have really mean? Is there a difference between 1980’s mammography and the digital mammograms of today?
The researchers in Canada drew the following conclusions: “Our data show that annual mammography does not result in a reduction in breast cancer specific mortality for women aged 40-59 beyond that of physical examination alone or usual care in the community. The data suggest that the value of mammography screening should be reassessed.”
Wow….that does seem to turn our routine procedures on its head…but not so fast.
As with many of these studies, it is important to really evaluate what we are being told. If we dig a little deeper into the report, we also see that in the group without the mammograms, those who ended up with breast cancer, had larger tumors (2.1 cm v 1.4 cm) and that the cancer was more likely to have spread into their lymph nodes (34.7% v 16.5%).
In addition to that, the women with larger tumors had a lower the survival rate. The study authors themselves state: “The 25 year survival was 77.1% for women with tumours of less than 2 cm, compared with 54.7% for tumours greater than 2 cm (hazard ratio 0.46, 95% confidence interval 0.37 to 0.58; P<0.001). “
The American College of Obstetricians and Gynecologists maintains its recommendation that mammography screening be offered annually to women beginning at age 40. They also state that there have been eight other randomized controlled trials that have shown mammograms do help prevent deaths for women in their 40s and 50s. In addition, data from numerous and much more recent observational trials have been published confirming a reduced mortality with modern mammography screening methods.
This is clearly a debate that has only just begun. The question for those of us in the trenches though, is what do we do now?
As we continue to get more and more information I would suggest that we all pay attention to any new data, but for now I would recommend sticking with the current recommendations for annual mammograms after age 40. Although there is always a risk of over diagnosis, from what we know today, it seems like sticking to the status quo of yearly mammograms is the safest approach.