Fewer Mammograms Means More Breast Cancer Deaths
Jan. 26, 2007 — -- It is a small statistic in a straightforward report. But its impact and implications are potentially huge.
From 2000 to 2005, the percentage of women age 40 and over who received a mammogram within the previous two years fell from 76.4 percent to 74.6 percent -- a 1.8 percent drop.
A 1.8 percent drop doesn't seem like much, so why all the fuss?
Because in real terms, this means that thousands of women may have undetected breast cancer and could potentially miss the opportunity to save their own lives.
This wasn't really unexpected by those of us who try to keep up with current mammography practices.
My colleagues at the American Cancer Society noted a year ago that there had been a decline in mammography-screening compliance. We were also aware that there appeared to be a decline in mammography in women on Medicare, a group that is at particularly high risk of developing breast cancer.
During the course of the past year, we have had discussions with several different groups, including insurers and quality-assurance organizations, who were concerned about their own observations that mammography-screening rates were dropping.
Then, at the San Antonio breast cancer conference in December, there was a stunning report that from 2002 to 2003 the number of new breast cancer cases diagnosed in the United States had actually decreased 7 percent.
Decline Threatens Breast Cancer Gains
We have been making considerable progress in reducing deaths from breast cancer, despite what has been up until recently a continuing increase in the number of women diagnosed with this disease.
More recently, the American Cancer Society reported that the number of new cases diagnosed in year-to-year comparisons actually appears to be leveling off.
But what will happen in the future with respect to deaths from breast cancer if the trend detected by the Centers for Disease Control and Prevention continues, is a source of great concern.
We know that annual mammograms for women at risk for breast cancer significantly decrease deaths from this disease.
Dr. Len Lichtenfeld is deputy chief medical officer for the American Cancer Society. You can view the full blog by clicking here.
None of the advances we have made in the treatment of breast cancer even begin to have value in the treatment of a woman's breast cancer unless she starts by taking care of herself and getting a mammogram every year.
As a result of the widespread availability and uptake of mammography in the United States, we have been able to increase survival rates from breast cancer. Today, for a woman whose breast cancer is found early and not spread to regional lymph nodes, the five-year survival rate is 98 percent.
Let's take a quick look at some numbers. These are just estimates for discussion purposes, but they at least will give you some perspective on the problem.
My colleagues tell me there are approximately 80 million women in the United States who should be getting a mammogram every year as recommended by the American Cancer Society.
But of those 80 million women, not all get an annual mammogram. In fact, we estimate that about 60 percent of women currently follow that recommendation.
So, if there is a decrease in mammography compliance (as measured by the CDC's standards), that would mean about 1.44 million fewer eligible women had a mammogram in 2005 compared with 2000.
Now, let's take the next important step in this analysis.
My colleagues also tell me that the rate of breast cancer found on mammograms is about 4 to 6 per 1,000 mammograms per year.
If 1.44 million fewer women had mammograms, that translates into about (and these are rough estimates) 5,760 to 8,640 women having a breast cancer that was not found in 2005.
Read that sentence again carefully: Thousands of women have undiagnosed breast cancer that would likely have been found if they'd had a mammogram in 2005, as compared with 2000.
These aren't breast cancers that don't exist. These are breast cancers that do exist and are not being diagnosed.
Reason for Decline Unclear
Why are we seeing this decline? Frankly, we don't have all the answers.
We know that the number of doctors specializing in mammography is declining.
Dr. Len Lichtenfeld is deputy chief medical officer for the American Cancer Society. You can view the full blog by clicking here.
We know that in some areas of this country, women are having problems getting access to mammograms in a timely manner.
We know that women who don't have health insurance or are less educated have a lower rate of mammography screening.
When the large decline in breast cancer incidence from 2002 to 2003 was reported in December, there was much speculation by experts interviewed in the media that this was due to the fact that women discontinued hormone replacement therapy as a result of a report in July 2002.
My own opinion, as I expressed in my blog entry at the time, was that although this may have had some impact, it wasn't logical to assume that every woman stopped her hormone replacements right after the article was published, and that breast cancers stopped occurring.
I thought that, although the decrease in HRT may have had something to do with declining diagnosis, there were likely additional explanations, including a decrease in the growth rate of some already-existing cancers.
And, I noted, declining mammography screening was quite possibly one of those reasons.
Complacency Could Cost Lives
So what is going to happen as a result of the observations in this current CDC report?
First, and most concerning, is that this may be just the tip of the iceberg and that this may be a very unwelcome trend. In a sense, these numbers may be the canary in the coal mine. We will certainly want to follow this very carefully.
Next, we need to understand exactly what is behind this decline. Is it limited to certain groups of women? The need to know why this is occurring is critical to our understanding of what we need to do to fix the problem.
Mammograms don't prevent breast cancer; they find it early in most cases. So, having more mammograms doesn't put you at less risk of finding breast cancer on the next study as you get older.
A comment on my blog from a breast cancer survivor noted that she was concerned that women were becoming complacent about getting mammograms because they stopped their hormone therapy.
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Dr. Len Lichtenfeld is deputy chief medical officer for the American Cancer Society. You can view the full blog by clicking here.
However, the risk of breast cancer for the average woman is only slightly increased because of the hormones. Almost all the risk of getting breast cancer for any one woman is simply due to the fact she is a woman, and is getting older (assuming there is no significant family or genetic history).
So is all of the publicity that has questioned the value of mammography having a negative impact on the behavior of women?
Study after study has demonstrated the value of mammography. We have seen declines in death rates from breast cancer, in no small part due to the contributions of mammography. The American Cancer Society stands behind its firm recommendation that women need to get mammograms.
But we also know that when the public message gets muddled, people react by ignoring the recommendations.
If that's the case, that is unfortunate because women will pay with their lives.
If we continue to see fewer women getting mammograms, then it is inevitable that we will see the tides turn in the wrong direction.
That won't be evident for several years, but it is likely going to happen unless we reverse this trend.
And that would be tragic.
Dr. Len Lichtenfeld is deputy chief medical officer for the American Cancer Society. You can view the full blog by clicking here.