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MRI Scans Recommended for Women at High Cancer Risk

March 28, 2007 at 9:22 AM EST
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JUDY WOODRUFF: For much of the past week, the subject of cancer has again captured national attention. Two public figures — Elizabeth Edwards, wife of presidential candidate John Edwards, and White House Press Secretary Tony Snow — disclosed their cancers had advanced.

And today, new guidelines are calling for expanded use of MRI scans for women who are at higher risk of breast cancer. To fill us in on the latest research is our health correspondent, Susan Dentzer. Our Health Unit is a partnership with the Robert Wood Johnson Foundation.

Susan, thank you for being here.

SUSAN DENTZER, NewsHour Health Correspondent: Thank you, Judy.

JUDY WOODRUFF: Let’s start with these new breast cancer guidelines that have come out by the American Cancer Society. Explain what those are, who they apply to.

SUSAN DENTZER: Judy, the average American woman will have a one out of nine chance of being diagnosed with breast cancer over the course of her lifetime. But some women will have a much higher risk, a one in four risk or even a one in five risk.

These are women who have some particular strong family history of breast cancer. And by strong, I mean they’ve been assessed according to various risk models that look closely at this or they have perhaps inherited one of several identified breast cancer gene mutations that we know are linked to breast cancer, a couple known as BRCA1, BRACA-1, or BRCA2, which are associated with breast and ovarian cancer.

And women with those genetic mutations will have as high as a 45 percent to even a 90 percent chance of developing breast cancer or ovarian cancer over their lifetimes.

So if you fall into any of those categories or you fall into another category, which is you’re a woman who’s also been treated for something called Hodgkin’s disease, and you’ve been treated essentially with radio therapy, you can also be at greater risk for breast cancer.

If you’re in any of those pools, the American Cancer Society now says you should be not just screened by routine mammography, which of course as we know for all women is recommended by the Cancer Society for routine annual screening, starting from age 40 on. In addition to mammography, the American Cancer Society says, you should also be screened with MRI.

MRI, magnetic resonance imaging, is a technology that is distinct from mammography, which has very low-dose x-rays that gives you a couple of different views of the breast. MRI is going to give you a cross-sectional view, much more refined.

And, in fact, if it’s also used with what is the equivalent of a kind of a dye, a contrast agent, it’s going to show, in much higher resolution, even very small cancers, tumors as small as a 100th of an inch or less.

So the Cancer Society says you should be screened with an MRI, if you fall into one of these high-risk groups, because that is going to do a much better job of detecting a cancer when it’s very small and very treatable.

NEJM study

JUDY WOODRUFF: So that's one new set of guidelines that came out today. Completely separately, the New England Journal of Medicine, another set of guidelines. Briefly, what were those about?

SUSAN DENTZER: Not guidelines in this case, but, in fact, a study that was very much brought out in time to coincide with the guidelines. This study looked at a different pool of women. These are women who already have been diagnosed with breast cancer in one breast.

And the question is, what do you do about concerns that that woman could also have the cancer in another breast? This study said that, for those women who have been diagnosed with one breast cancer, MRI screening is also an effective technology.

This study essentially took about 970 women who had been diagnosed with cancer already, gave them all MRIs, and, in fact, it found in about 3 percent of the women overall, a tumor was detected in the other breast that was not already present or shown to be there by mammography or a so-called regular breast exam.

So that study seemed to indicate this was a very effective technology to use for those particular women, as well.

Unanimity in using MRIs?

JUDY WOODRUFF: So two sets of findings, recommendations. Does this represent unanimity in the medical community?

SUSAN DENTZER: By no means, because there rarely is. There's probably a little bit more unanimity around the notion of screening a woman who's already had cancer in one breast with MRI for the second one, mainly because, for one thing, that gives a woman a much fuller sense of what her treatment options are or should be.

Many women with cancer in one breast will elect to have the other breast surgically removed, also, just because they're worried about it. If you can give them an MRI and give them some confidence that they don't have cancer in that other breast, women just have a better sense of what their treatment options should be. So there's probably more unanimity there.

On the question of screening women at higher risk, screening always brings about debates, because a big issue in cancer screening is, did you establish that somebody had a cancer sooner, and therefore treated them appropriately, and therefore you actually extended their life or made them less likely to die? Or did they die about the same time they would have anyway, they just knew that they had cancer longer and you treated it further in the process?

And so there's a lot of concern that this type of study and the guidelines that the American Cancer Society unveiled are not based on the kind of evidence that would give you real assurance that there would be real deductions in deaths and expansion of life, extension of life.

The American Cancer Society and others who are in favor of this kind of screening say, we probably could never do the kinds of trials that would give us unequivocal evidence, and this is the best evidence we have to treat women in the here and now.

Detecting cancer early

JUDY WOODRUFF: But there are those who would hold out for that. Just quickly, Susan, in the real world, magnetic resonance imaging, expensive procedure, these MRI devices, is there the insurance coverage to do this? And are there the equipment? Is there enough equipment out there to take care of it all?

SUSAN DENTZER: There probably are enough MRIs in America to do this. The real issue is more, do we have radiologists who can read these scans appropriately? And even more important than that, do people understand when things that are found should be biopsied?

In the study that we just talked about, 120 women were actually biopsied. And in 90 of those cases, the lesions were found to be benign. There was not cancer. There was a high false positive rate.

You have to be able to know when something is really a cancer and really needs treatment. And that's really going to be the bigger question: Do we have enough people who really know that, enough sophisticated centers that can screen women appropriately?

JUDY WOODRUFF: And, finally, Susan, bringing it back to the news of the last week, Mrs. Edwards, Elizabeth Edwards, and more recently Tony Snow, does what we've learn today in any way add to our broader understanding about the causes of cancer, our ability to prevent it? Because all of us, I think, are more focused on it as a result of what we've learned.

SUSAN DENTZER: I think what we know is that one in three Americans now will face a diagnosis of cancer, and the cancer caseload will probably double over the next 10 to 15 years. So the name of the game is going to be early detection.

We want to detect cancers as early as possible, when they're localized and haven't spread, as has been now shown to be the case in both Tony Snow and Elizabeth Edwards. Those cancers are much less treatable, and survival records are much poorer. So you want to find cancers early as possible.

And screening is one mechanism to do that. And as we'll see in our forthcoming piece, a lot of hopes are now being pinned on cancer biomarkers as another tool for early detection and also monitoring of the effectiveness of treatment over time.

It's pretty clear that both Tony Snow and Elizabeth Edwards would have benefited if their treatment could have been monitored in a new way, by evaluating cancer biomarkers, that probably would have given an even better indication of the state of their disease.

JUDY WOODRUFF: All right. Susan Dentzer, thank you very much.