Are Mammograms as Effective as We Thought?Apr 2, 2014
We’ve known that mammograms can prevent breast cancer. But can the radiation from those mammograms actually cause cancer? Are they effective? Should women even continue screening for breast cancer? Dr. Tom Miller and Dr. Nicole Winkler discusses the controversial questions surrounding mammogram screening. They also address the debate on when a woman should get her first mammogram, and how often.
Dr. Tom Miller: Screening to prevent breast cancer. We're going to talk about that next on Scope Radio. This is Dr.Tom Miller.
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Dr. Tom Miller: I'm here with Dr. Nicole Winkler. She is an assistant professor in the department of radiology and also a specialist in breast imaging. How are you today, Nicole?
Dr. Nicole Winkler: Great, thank you for having me.
Dr. Tom Miller: There's been some interesting discussion in the press based on some research over the last few years that mammograms may not save as many lives as we thought. Do they save lives? Should women continue screening for breast cancer?
Dr. Nicole Winkler: Absolutely. That's a great question, because it's very controversial. Women are hearing different opinions from all directions, and it's hard to know what they should do. We recommend that screening mammograms are done every year starting at age 40. We do think that mammography saves lives. We have several randomized controlled trials that have shown a mortality reduction of about 30%. We think that may even be underestimated.
Dr. Tom Miller: You still think it's very important.
Dr. Nicole Winkler: Absolutely.
Dr. Tom Miller: Sometimes I'm confused by the literature myself. My patients will come in quoting something they saw on the Internet that maybe they don't need a mammogram as often, or maybe it doesn't help as much, and what should they do. I think that's very helpful. What about the interval? You mentioned beginning at age 40. There is some controversy about when to begin. Should it be 50, or 40, or even lower?
Dr. Nicole Winkler: There is. The U.S. Preventive Task Force Services recommends age 50, but we actually think...
Dr. Tom Miller: That's a conservative task force group I think, right?
Dr. Nicole Winkler: Yes, yes.
Dr. Tom Miller: There are several others, but I guess...
Dr. Nicole Winkler: There are several others. Many groups have challenged that recommendation. We follow the American College of Radiology and the American Cancer Society guidelines, and that's every year starting at age 40.
Dr. Tom Miller: Is it true that more lives are saved in women who begin screening at the age of 50 than between the ages of 40 to 50? That's been some of the things that I've heard.
Dr. Nicole Winkler: Yes.
Dr. Tom Miller: Maybe we screen between this 40 and 50 and it doesn't help as much.
Dr. Nicole Winkler: We still think that it helps. The mortality reduction is a little bit less than if you start at 50, but in women 40 to 50 they actually tend to have a little more faster growing cancers. That's why the annual mammogram is so important rather than bi-annual mammograms. We have studies that show that there is reduced mortality in that age range.
Dr. Tom Miller: What about 50 and over? Some of the women come in and say this is uncomfortable, I've heard you can do it every two years. Is that okay compared to every year? What's your thought on that?
Dr. Nicole Winkler: I think it's a good discussion to have of the pros and cons. The pros are if you have a cancer that's maybe very subtle, slow growing, we would be able to maybe pick that up sooner if you have it a year before than two years later. Also, with calcifications that's a sign of an early cancer, and if you let that go two years by the time you come in for your screening mammogram you may have a 2 centimeter cancer as opposed to a 1 centimeter cancer if you had come in every year. The goal of a screening mammogram is to find cancers early and to find them before they've gotten to the lymph nodes. Mammograms don't prevent breast cancer. They just find them early. If we do it every year we do think that that gives us more of a chance of finding a cancer.
Dr. Tom Miller: That's interesting. You mentioned that mammograms don't cause cancer, but I've even had patients come in and say they're reluctant to do a screening because they're worried about the radiation, because they've read that radiation from mammograms could cause cancer. What's your thought on that as a radiologist?
Dr. Nicole Winkler: I think it's an important question, because this is a medical device and it is a small dose of radiation to a patient. We think that it's a very low dose. I think having it annually doesn't affect your overall mortality as to whether you're going to get cancer, but there still are a lot of questions about that. We don't actually know from long term data what happens. We're still in that phase of mammograms are still pretty young. We've only been doing them for about 40 years.
Dr. Tom Miller: Also, the new X-ray machines, the digital machines, don't they use less radiation? Is that right?
Dr. Nicole Winkler: They do, yeah. We have regulations that we have to stay below a certain dose, and we're well below that dose here at Huntsman. That's probably the case at most American hospitals.
Dr. Tom Miller: That also brings up another question, because I'll have a patient come in and say because of the radiation I'd rather have an M.R.I. because I hear there's no radiation involved in an M.R.I. What's your thought on the different types of screening for breast cancer? Could we use an M.R.I. or other modality like ultrasound?
Dr. Nicole Winkler: There is no replacement for a screening mammography. Breast M.R.I. does not see the early calcifications that we would see on a mammogram. The other disadvantage of M.R.I. is that it's actually a pretty long exam. It's 45 minutes. They have to put an I.V. in and give contrast. It's an expensive test, and it has a high probability of us finding some things that are benign but that we have to work up.
Dr. Tom Miller: No procedures that don't show anything.
Dr. Nicole Winkler: Yes. We really only recommend breast M.R.I. in women that are high risk with a lifetime risk of over 20%.
Dr. Tom Miller: All right. For our older patients, older women, when is there a safe time to stop screening for breast cancer, or is there?
Dr. Nicole Winkler: There actually is not any really precise time that you should stop. The studies that were done on the benefit of screening mammography were for ages up to 74. No one really knows over age 74 whether mammograms help or not. What we usually recommend is that a woman who is 75, and in good health, and could live another 20 years probably should continue to have screening mammograms, whereas a 65 year old who has a lot of medical problems and maybe is not going to live for 10 more years probably should stop screening mammography. We usually say if your life expectancy is about five to seven years, and no one knows what their life expectancy is, then you could continue mammograms until you think probably not more than five years. The other thing I want to say about that, too, is women who get screening mammograms should be willing to continue on with whatever work up needs to be done.
Dr. Tom Miller: Breast tissue. Some of my patients will come in and say doctor, I don't have enough tissue to have a mammogram; do I really need a mammogram? A corollary to that is what about men and mammograms. Do they need to be screened for breast cancer? What's the thought on that?
Dr. Nicole Winkler: Men do not need to be screened. There is a little bit of controversy about men that have genetic mutations like BRCA mutations, but there is not really any screening recommendations for men.
Dr. Tom Miller: What's a BRCA?
Dr. Nicole Winkler: It's a breast cancer mutation.
Dr. Tom Miller: Gene, abnormal gene.
Dr. Nicole Winkler: Gene, an abnormal gene.
Dr. Tom Miller: That predisposes for breast cancer.
Dr. Nicole Winkler: Exactly.
Dr. Tom Miller: Right. Should all women have a mammogram, or can all women have a mammogram depending upon the tissue?
Dr. Nicole Winkler: Every woman can have a mammogram. If you've got skin we can squeeze it.
Dr. Tom Miller: The take home message for our audience is?
Dr. Nicole Winkler: The take home message is mammograms are recommended in all women age 40 and over annually. The time to stop is a little bit controversial, and you should have that discussion with your doctor probably around age 75.
Dr. Tom Miller: You heard it from Dr. Winkler. Thanks very much.
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