October is breast cancer awareness month.
Breast cancer awareness seems to be everywhere. And yet confusion about screening for breast cancer is ubiquitous.
Should you get a mammogram? Should you examine your own breasts? And lately, should you even have an annual exam with your doctor?
I admit that I might be biased because I am a doctor, but to me, the last question is the most compelling reason to see your doctor once per year. “Recommendations” about what screening you should have, what medications are best (or worst), how much exercise you should get, what type of exercise you should get, what vegetables are good for you (or bad for you?!) and what supplements you should take (or should not take) are in the newspaper and online every day. But they seem to change every day. It seems that one day you are supposed to take calcium for your bones and the next day you are supposed to stop taking calcium because it damages your heart. Your doctor trained for many years to learn to evaluate new studies and to parse out which recommendations should apply to you. Your doctor must engage in continuing education each year to keep those skills sharp and to keep up with current recommendations as they apply to you. The best reason to see your doctor for an annual exam is to review what you, as a complete and complicated individual, should be doing to maximize your health and prevent disease.
Now, back to breast cancer awareness.
The evidence is strong that mammograms pick up breast cancer early, when it is most easily treated and survival rates are highest. Breast cancer deaths have been steadily decreasing, due both to early detection by mammograms and to better treatment options. My patients will often tell me that they are not worried about breast cancer because there “is none in my family”. It is very important to know that one in eight (12.5%) women will get breast cancer, just by virtue of having breasts. Having a family history can increase that risk, but even without a family history, the risk of developing breast cancer is significant. Experts all agree that mammograms save lives. Mammograms can pick up a cancer up to two years before it would be palpable by a physical exam. The real question is when should you start and how often should you get them?
The US Preventive Services Task Force (USPSTF) has released recommendations that have been extensively reported in the media. However, the understanding of these recommendations remains confused. Many people have interpreted the recommendations to mean that women under age 50 should not be getting mammograms and that is simply not the case. The USPSTF now recommends that a woman aged 40-49 should make an individual decision about whether the potential benefit of getting mammograms outweighs the potential harm of mammograms for her. How in the world can you do that without spending your life on your computer looking up statistics and studies? This would be a great time to talk to your doctor!
Until today, every medical association recommended starting mammograms at 40. The American College of Obstetricians and Gynecologists. The National Comprehensive Cancer Network. The National Cancer Institute. Either every year or every 1-2 years. Just today, while I was writing this blog, the American Cancer Society updated its recommendations. They now recommend starting mammograms at 45 instead of 40, continuing yearly until age 54 and then continuing every other year for as long as you are expected to live another 10 years. Fascinating if you can predict when you will die. Hard to decide if you cannot.
So, why the difference in recommendations? The USPSTF makes recommendations based on value to a population. How prevalent is the disease? How many screenings do you have to perform to find one cancer? And, most importantly, how much does it COST to do all those screenings to find that one cancer? These are valid and important questions, especially when we all know that health care resources are not unlimited. The USPSTF and the medical societies make the cut off for “worth” at different levels.
Almost 50,000 breast cancers are diagnosed in women between the ages of 40 and 49 each year in the United States. Almost 5,000 of these women will die of their disease.1 Medical societies are adamant that these cancers are worth finding and treating. Adamant that these lives are worth saving. We can look at it another way. One out of 42 women in their 50’s will be diagnosed with breast cancer. One out of 69 women in their 40’s will be diagnosed with breast cancer. Those statistics are not that different. To give these numbers some perspective, we typically recommend screening couples for genetic disorders that are much less common than one out of 100 before they attempt to conceive.
If you screen women in their 50’s with mammogram, you have to do about 1300 mammograms to prevent one cancer. The USPSTF has decided that those numbers are worth it and feels that this recommendation is based on solid data. You have to do about 1900 mammograms to prevent one cancer if you screen women in their 40’s. The medical societies have decided that these numbers are worth it and base their recommendations on the same data.
Much has been made in the media about balancing the risks and benefits of mammograms. Many of my patients have interpreted this to refer to the risks of radiation. The amount of radiation you receive from a full set of films on a mammogram is about the same as the amount of radiation you get from just living and walking around the earth in two months. The increased risk of cancer from this amount of radiation is on the order of hundredths to thousandths of one percent.2 So, the amount of radiation received with a mammogram is not actually risky. The real risks of mammogram include the discomfort of the exam, the possibility of needing to undergo biopsy for what ends up being a benign abnormality or even treatment for an early, slow growing cancer that was found on mammogram but would have never killed you. These risks are real. Most of us think these risks are outweighed by the possibility of finding and curing a potentially deadly cancer but some of us may make a different assessment. Your doctor can help you determine the right answer for you.
Between 50 and 74, the USPSTF recommends mammograms every two years. Most of the medical societies (except for the National Cancer Institute and as of today, the American Cancer Society) recommend every year after age 50. The time from when a breast cancer can be seen mammographically to the time it can be felt on exam (the sojourn time) is between two and four years. Waiting two years between mammograms decreases the likelihood that a breast cancer will be picked up at the earliest stages of disease, when it is most treatable and most curable.
After age 75, mammograms still pick up breast cancer and pick it up early, but it is less clear that there is a benefit in prolonging life. Again, these recommendations are based on population statistics. For a healthy, active 75 year old, continuing mammogram screening might be more important than for a 75 year old who is plagued by more serious health problems that are more threatening to her life than her risk of breast cancer. Each woman should discuss the decision to continue mammograms after age 75 with her doctor.
Finally, there has been much debate about whether women should do a self breast exam. I have never understood this debate. Monthly self exams have probably never been necessary. But what is the harm in examining your own breasts several times a year so you know what your normal is? The new advice is “breast self awareness”. How can you be aware of what your normal breasts feel like if you never examine them? There is nothing magical or medical about a breast self exam. The only thing you need to know is that if you are menstruating, the best time to check your breasts is after your period, when they are no longer tender and swollen. It should not be stressful and it should not take you longer than a minute or two. Mammograms, for all their benefits, do miss 10% of breast cancers. There are no costs to breast self exams and there is no pain involved.
When all is taken into consideration, all societies are basing their recommendations on the same data. Each society is making a different judgment call about when the risks and costs of screening outweigh the benefits. My general advice to my patients is to do breast self exams two or three times per year, start mammograms at 40, do them every 1-2 years until 50 and then yearly until the mid-70’s. After age 75, we should talk about what you want to do. If you have a family history of breast cancer, you should start mammograms at an age that is 10 years before the person in your family was diagnosed. Of course, this general advice is then tempered by what each woman finds important for her, what her risks are and if her tolerance for the possible false positive test is more or less than her tolerance for possibly missing an early cancer. For women who have a family history suggestive of a cancer gene, please see my previous blog, https://melaniemarinmd.com/breast-and-ovarian-cancer-gene-testing.html, and talk to your doctor!
References:
1 http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-042725.pdf
http://www.cancer.gov/types/breast/patient/breast-screening-pdq
