Breast Cancer Screening: The Quiet Truth
The political brouhaha that followed the new guidelines on mammograms has now died down, maybe enough so that patients can start to absorb the quiet truth about breast cancer and the role of mammogram screening.
The National Breast Cancer Coalition has worked since 1991 to get Congress to fund research and appropriate treatment for this disease. The Coalition believes in sticking to the facts and analyzing closely the research studies that have been published about what mammograms can and cannot do for women who aren’t aware of a lump in their breasts.
Here is an excerpt from their discussion of the US Preventive Services Task Force recommendations:
Has breast cancer screening had a significant impact on mortality from breast cancer?
No, over 40,000 women continue to die of breast cancer each year, despite the emphasis on breast cancer screening in our country. To change this, we must address the facts about breast cancer and not simply accept what we want to believe. The fact is that all breast cancers are not equal and that we don’t currently have tools for “early detection” that are good enough for the life-threatening breast cancers.
But doesn’t early detection save lives?
Not necessarily. Some breast cancers are slow-growing and have a good prognosis, whenever they are found, whether small or large. Other breast cancers are aggressive and fast growing, and we don’t have the tools to catch them early enough or treatments that will work.
Why doesn’t mammography work as well for women in their 40s?
Younger women have more dense breast tissue, making mammography less accurate. Also, mammography is better at detecting slower growing tumors more common in older women, than the fast-growing, aggressive tumors more often found in younger women. And the balance of benefit vs. harm changes as women get older since the likelihood of breast cancer increases with age. The disease is relatively rare in younger women.
But shouldn’t a woman in her 40s have a mammogram if she feels a lump?
Certainly. The Task Force recommendations are meant to be guidelines for broad public health policy for healthy women with no symptoms, and an average risk for breast cancer. These guidelines are not meant for any woman with an increased risk or for any woman who feels a lump or change in her breast. Women who have any concerns need to visit their doctors and may need diagnostic mammograms. Mammograms taken to assess a problem are not the kind of mammograms we are talking about with these guidelines.
What’s the harm in trying to detect breast cancer early, even if our methods don’t work that well?
The harms from screening too early or too often include increased false positives, leading to increased imaging and radiation exposure, biopsies and scarring that can affect the accuracy of future mammograms, and anxiety. There is also the harm of overdiagnosis of breast cancer. This would involve treatment of cancers that would never be life threatening, and treatment of cancers that may regress, or go away on their own. The treatments for breast cancer are not aspirin, they are toxic and can be life threatening; the scenario of overdiagnosis should not be taken lightly.
The cancer coalition supports the Task Force’s recommendation that women who are not in a high risk category (from a family history or presence of the BRCA gene) start thinking about mammograms around age 50, not age 40.
Here is another useful summary from the National Breast Cancer Coalition: 31 Myths and Truths about breast cancer. You can read it here.
We have discussed the statistics behind breast cancer screening in several entries on this blog. Read them here and here and here. My belief is that women need to understand the numbers and then make a personal choice. Politicians don’t need to enshrine mammograms as some sort of constitutional right, as happened in the US Senate not long ago. We need more compelling evidence before this screening device goes onto the “do not touch” pedestal.