Breast imaging is a complex topic that can be difficult to navigate. We had the privilege of hosting University of Pittsburgh Medical Center breast imaging radiologist Dr. Amy Kelly in a recent “Ask the Expert” webinar to discuss the nuances of screening guidelines, dense breasts, and different screening mechanisms. We’ve transcribed part of the discussion on mammograms to provide you with a recap of the conversation. You can also visit the full webinar recording below.
The following questions and responses have been lightly edited for grammatical purposes.
1) When should women get their first mammogram and what risk factors should be considered? There seems to be a bit of confusion when it comes to the screening recommendations.
Dr. Amy Kelly: That’s a great question and there is unfortunately a lot of confusion about the recommendations, so this is an important topic to address.
The major organizations, such as the Society of Breast Imaging, the American College of Radiology, the American Cancer Society, and the NCCN Guidelines, recommend that women of average risk start screening mammography at age 40 and continue every year thereafter.
We also recommend that women talk with their doctor about potential risk factors by age 25. This is because some women are at elevated risk and may need to start screening before age 40. It’s important for us to identify those women so that we can start screening earlier and potentially diagnose breast cancer that could otherwise be missed.
These higher-risk women include those with a genetic predisposition to breast cancer (such as BRCA gene mutations), women who had chest radiation for Hodgkin’s lymphoma before age 30, and women with a strong family history of breast cancer, specifically if a first-degree relative was diagnosed with premenopausal breast cancer. These women may benefit from earlier screening to catch any potential cancers as early as possible.
For example, if a patient’s mother was diagnosed with breast cancer at age 45, we would suggest starting screening 10 years earlier than that relative’s diagnosis. So, if my mom was diagnosed with breast cancer at age 45, I should start screening mammography at age 35.
That being said, we don’t typically recommend screening mammography for women under 30. For women at very high risk, such as those with a BRCA mutation, the societies recommend starting breast MRI screening from ages 25 to 29, and then adding screening mammography at age 30, along with continued MRI, for those very high-risk patients.
2) What’s the difference between a screening mammogram and a diagnostic mammogram?
Dr. Amy Kelly: This is kind of a bread-and-butter breast imaging question. Screening mammograms are just that, a preventive screen for breast cancer. They’re done in asymptomatic women who have no signs or symptoms of breast cancer. They’re free, readily available, and recommended once a year. You don’t need a prescription for a screening mammogram. It’s a quick, in-and-out type of exam, and the results are given to you at a later time.
The difference between a screening mammogram and a diagnostic mammogram is that a diagnostic mammogram is reserved for patients who have signs or symptoms of breast cancer, such as a palpable lump or any overlying skin changes. It’s also done when we’re currently working something up on imaging. For example, if we call a patient back from her screening mammogram, if we’re following findings that are considered likely benign, or if we’re working up a new diagnosis of breast cancer. These cases are done in the diagnostic setting.
For a diagnostic mammogram, you do need a prescription, and there may be a copay involved. It’s always good to check with your insurance company about that. Typically, the results of a diagnostic study should be given to you before you leave the breast imaging department.
3) How dangerous is the radiation from mammograms and does it increase your risk for developing cancer?
Dr. Amy Kelly: There’s a lot of talk about that online and on social media, and rightly so. I do want to say that as radiologists, radiation exposure is at the forefront of our concern. It’s something we take very seriously, and in mammography specifically, it’s something that’s highly regulated and checked on a daily basis. For example, at our imaging center, we check the dose for the mammogram machine every single day before we image any patient.
I want to validate the concerns that women have about radiation because it is a real thing, and I don’t want any patient to think that we dismiss that in any way. Now, that being said, I do want to hopefully reassure some patients that the radiation dose for mammography is very low. To give you specifics, the radiation dose is measured in millisieverts (mSv). For one view, it’s about 0.1 mSv, so for a typical 4-view mammogram, like a screening mammogram every year, the total dose is about 0.4 mSv.
You may hear a lot of analogies online, like how this dose is equivalent to about seven weeks of background radiation, or similar to a transatlantic flight. That’s true, but it helps to put it in perspective of the dose. We really have no scientific evidence of any link or connection between radiation exposure and adverse effects of doses below 50 mSv. Scientists and physicists have made a statement saying they strongly discourage any theoretical risk estimates for radiation below background. For context, background radiation for a year is about 3-10 mSv.
[As physicians,] we are constantly thinking about the patient. First do no harm and we’re also weighing the risks and benefits of everything we do. The risk of breast cancer is real. I think all of us know of someone who’s been affected personally. It is prevalent. The 1-in-8 chance of being diagnosed with breast cancer is a real risk.
I would just reassure patients that the risk of a screening mammogram is very low, and the benefits of doing that screening mammogram and finding a potential cancer are so important and far outweigh any potential risk, one that we really don’t have scientific evidence to prove.
Another thing I found quite interesting when thinking about all this is that if someone smokes a pack of cigarettes a day for just one year, their dose of radiation from tobacco is about 150 mSv. There are definitely things we can do to lower our risk, lifestyle modifications and things like that, but skipping your screening mammogram is not one of those.
View Dr. Kelly’s full webinar recording here.
