New mammogram guidelines are spurring huge controversy

This controversy is receiving massive media coverage for the second consecutive day, and being covered on every major network — the controversy is swirling around the new breast cancer screening guidelines from the US Preventative Services Task Force (USPSTF). The news is sparking a surprising amount of anger, skepticism, and confusion among women and those who love them, as well as healthcare professionals and and public health experts.

The CBS Evening News (11/17, story 3, Couric) reported that “new government guidelines for breast cancer screening” that “say routine mammograms are not necessary for most women in their 40s” are “upsetting many patients and their doctors.” The US Preventive Services Task Force recommends that “women at low risk should not get screened until they’re in their 50s and then every other year.”

NBC Nightly News (11/17, lead story, Williams) reported that “a generation of American women has grown up believing that turning 40 means getting your first mammogram,” and “a change that big, that sudden, isn’t being taken lightly. Women are surprised, they’re angry, they’re skeptical. Some are scared they’re going to miss something.”

The New York Times reports that “there remains … confusion” among women who are “uneasy with the idea of shifting” their “own approach to breast cancer detection, based on new federal guidelines without first knowing the medical specifics behind them, and also what oncologists and breast cancer awareness groups were saying.”

Meanwhile, “major medical centers from across the country, including the Mayo Clinic and MD Anderson, are rejecting the new recommendations,” ABC World News reported.

The guidelines, “which put the [panel] at odds with two major cancer organizations, came under immediate fire from some breast cancer specialists,” McClatchy reported. Both “the American Cancer Society and the National Cancer Institute said they had no plans to back down from their current” recommendations that “annual mammograms for women” start “at age 40.”

Many physicians are being reported as saying “that they were simply not ready to make such a drastic change,” the New York Times reports.

But, overall “most of the doctors … said they would inform younger women that the recommendations said they did not need mammograms if they were low-risk,” while also pointing out to patients “that groups like the American Cancer Society and the American College of Obstetricians and Gynecologists are sticking to the earlier guidelines.”

And, I think that is the tact that I’m going to take. I’ve always advocated that we physicians let our patients know all of their options, with the costs, risks, and benefits of each option and let them decide.

The unanswered question is how insurance companies are going to respond. My guess (and, it’s only a guess) is that once the furor calms down, we’ll begin to see many or most of them using the USPSTF recommendations next year.

It’s important to note that the USPSTF panel, however, is not telling women don’t get a mammogram until you’re 50. They’re just saying it’s not a blanket statement that they have to get one at 40. They’re just saying that there is more risk than benefit to mammograms in low-risk women in their 40’s.

So, I join the panel in urging women to “discuss the pros and cons” with their physicians.

The Salt Lake Tribune is reporting that the task force “updated its guidelines after it commissioned a team of researchers to perform computer-simulation models.”

The team examined “how women would fair if they received mammograms at different ages, and with varying frequency,” finding that “the potential harms of screening … didn’t outweigh the benefits for women in the 40- to 49-year-old age group by much.”

Experts note, however, that the panel “had an absence of clinicians … that is, doctors that are working in the trenches, with breast cancer patients.” Some also argue that “it’s wrong to equate saving lives with the angst caused by false positives” from mammography.

True enough, but what I’m not seeing anyone report is the fact that the current breast cancer screening recommendations may be fueling over-diagnosis of breast cancer. According to a report in Reuters News, “Roughly one in three breast cancers detected in publicly organized mammography screening programs is over-diagnosed — meaning that the cancer will not cause symptoms or death in the woman’s lifetime.”

The study was released in the British Medical Journal this last July and brings to the front a major risk of mammograms in women in their 40s, namely, as elucidated in one editorial, “Lesions that are detected at screening but which would not have surfaced clinically in the lifetime of the individual constitute overdiagnosis, the major form of harm associated with screening programme.”

The editorial adds, “A secondary issue is the question of overtreatment of cancers that would progress but are diagnosed at a very early stage.”

We face similar issues with prostate cancer screening, that I’ve discussed in previous blogs. The New York Times got it right when it reported “Blanket screenings do come with medical risks. A recent European study on prostate cancer screening indicated that saving one man’s life from the disease would require screening about 1,400 men. But among those 1,400, 48 others would undergo treatments like surgery or radiation procedures that would not improve their health because the cancer was not life-threatening to begin with or because it was too far along. And those treatments could lead to complications including impotence, urinary incontinence and bowel problems.”

In other words, prostate cancer screening can save lives. It’s just that it is more likely to cause harm than good.

You see, of the 1400 men screened, 1341 men would get good news and have no harm (other than the cost of the blood test and digital rectal exam). And, 48 men would get the unnecessary bad news and unnecessary treatments. But, and this is critical, 1 man would have his life saved.

And, each man I face in the office is potentially that one man.

I’ve not seen where anyone has done this same calculation for mammogram screening for women age 40-49, but it has been done for women age 50 or greater in an editorial om tje British Medical Journal earlier this year.

The editorial concluded that for every 1000 women, age 50 or over, undergoing annual mammography for 10 years, 1 life will be saved. However, 10 women will be overdiagnosed and treated needlessly; 0 to 15 women will be told they have breast cancer earlier than they would otherwise have been told, but this will not affect their prognosis; and 100 to 500 women will have at least 1 “false alarm” (and about half these women will undergo biopsy).

In other words, of the 1000 women screened, between 475 to 890 women would get good news and have no harm (other than the cost and discomfort of the mammogram). And, between 110 to 525 would get unnecessary bad news and unnecessary treatments. But, and this is critical, 1 woman would have her life saved.

Remember, screening is a balance between risk and harm not just for the population but at the level of each and every person screened. For every one woman saved, in this calculation, between 110 and 525 could be harmed.

Another analysis concluded, “for every 2000 women invited for screening throughout 10 years, one will have her life prolonged and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings.”

Instead of comparing lives saved to lives harmed, another science blog has compared women saved to women overdiagnosed and says, “Zackrisson and colleagues reported 62 fewer deaths from breast cancer and 115 women overdiagnosed — a ratio of one death avoided to two women overdiagnosed. Recently, Gøtzsche and colleagues argued in the BMJ that the ratio is one to 10. For many women, the tipping point may be within this range. Careful analyses that explicitly lay out their assumptions and methods, which will improve the precision of these estimates, are sorely needed.”

Now, I’ll be facing the same issue (likely with even worse numbers) with the women aged 40 – 49 who come to see me. If they are low risk, a screening mammogram, at least according to the USPSTF, is more likely to cause her harm than good.

But, and this is critical, there are lives to be saved. And, each 40 to 49 year-old woman I face in the office is potentially that one woman.

The Task Force says, “The harms resulting from screening for breast cancer include psychological harms, unnecessary imaging tests and biopsies in women without cancer, and inconvenience due to false-positive screening results.”

In other words, in breast cancer screening for women, just like prostate cancer screening for men, a few deaths would be prevented by mammogram testing in women age 40-49, but, at least in the USPSTF calculus, that is outweighed by the risks and worry caused for many more women by misdiagnoses, overdiagnoses, and in many cases unnecessary treatments, biopsies, and surgery.

Said another way, in a blog by a British breast cancer expert, “it is becoming clear that mass screening programs of the ‘one-size-fits-all’ variety for breast cancer are probably not doing as much good as advertised or are arguably doing more harm than previously expected.”

Another editorialist in Britain says, “Mammography is one of medicine’s ‘close calls’ — a delicate balance between benefits and harms — where different people in the same situation might reasonably make different choices. Mammography undoubtedly helps some women but hurts others. No right answer exists, instead it is a personal choice.”

However, virtually all of my female patients are hypersensitive to the possibility of breast cancer for them, no matter how low the risk. So, my guess, is that most will choose for the screening. And, that’s okay by me. Just so their decision is one that’s informed by the best scientific data.

The bottom line, I join the panel in urging women to “discuss the pros and cons” with their physicians and make a decision with which they are most comfortable, irrespective of whether the screening is covered by an insurance company or not.

And, to inform that choice, women and their healthcare professionals need a simple tabular display of benefit and harms of screening mammography for women age 40 – 49 years old — a balance sheet of credits and debits, potential benefits and potential risks — and sooner rather than later.

As one expert has written:

The problem in changing the way that screening programs for breast cancer are done is likely to be convincing women that a more selective approach to mammographic screening is desirable.

To people not educated in cancer, it makes intuitive sense that detecting cancer earlier will result in better outcomes, and it is hard to explain the down side, namely over diagnosis, unnecessary biopsies and treatment, and the emotional distress that such false positive diagnoses make.

Also, the maintenance of public and therefore political support often depends upon keeping the message as simple as possible.

Including a discussion of the risks of mammography will likely be seen by many public health officials as “muddying the waters” and harming their efforts to promote screening.

Moreover, great care has to be taken to make sure that the public understands that this discussion is only about the screening of asymptomatic women. Women with breast masses or other symptoms worrisome for cancer should not be led to refuse mammograms because of this discussion.

Two other brief items from the USPSTF. One on the doctor doing a clinical breast exam (CBE), and the other on women doing self breast exams (SBE):

  • The USPSTF concludes that the evidence is insufficient to recommend for or against routine CBE alone to screen for breast cancer. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.
  • The USPSTF recommends against teaching breast self-examination (BSE). The USPSTF recommends against (BSE) as there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.

So, I’ll continue to provide CBE during my preventive medicine visits for women, but I won’t be having my nurse teach BSE anymore. If a patient wants to do monthly BSE, again, I’m okay with that.

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2 Responses to New mammogram guidelines are spurring huge controversy

  1. Debra Deyton says:

    Hi, Dr. Larimore, I’m confused as to why JUST the mammogram is so harmful. It would appear to me that the more extensive testing that follows a mammogram would be considered the culprit for a mis-diagnosis. I am 53 years old but I recall once in my late thirties when my mammogram was followed up with a coned-down view and an ultrasound that ultimately cleared any potential diagnosis. In my case, a biopsy was not required but I wonder what harm a biopsy would do. I haven’t studied to learn. My view is that a simple routine mammogram is harmless and any further testing should be examined carefully before moving into the treatment phase. I would not want to be that patient who received a fatal diagnosis because insurance required a 2-year wait for a mammogram. Thank you for discussing this topic.

    Debra Deyton

  2. Dr. Walt says:

    Hi Debra. Great question and I appreciate you posting it.

    First, to the question of potential benefit. The USPSTF says, “For women aged 40-49, the evidence that screening mammography reduces mortality from breast cancer is weaker, and the absolute benefit of mammography is smaller, than it is for older women. Most, but not all, studies indicate a mortality benefit for women undergoing mammography at ages 40-49, but the delay in observed benefit in women younger than 50 makes it difficult to determine the incremental benefit of beginning screening at age 40 rather than at age 50.” (http://www.ahrq.gov/clinic/3rduspstf/breastCancer/brcanrr.htm)

    They go on to conclude, “Analyses of individual studies suggest that at least some of the mortality reduction is due to early detection of tumors before age 50, but definitive estimates of the proportion of benefits due to early screening cannot be made.” So, there MAY BE a benefit to screening between the ages of 40-49, and there MAY NOT BE.

    However, as to your important question of potential harm, the USPSTF says this: “Similar to other cancer screening tests, the large majority (80 percent to 90 percent) of abnormal screening mammograms or CBEs are false-positives.”

    And, it’s these “false positives” that cause harm.

    Why?

    The USPSTF says, “These (false positives) may require followup testing or invasive procedures such as breast biopsy to resolve the diagnosis, and can result in anxiety, inconvenience, discomfort, and additional medical expenses.”

    They point out that “In one large community study, 6.5 percent of screening mammograms required some additional followup and, over a 10-year period, 23 percent of all women had experienced at least one abnormal mammogram.”

    Therefore, “The cumulative risk for a false-positive result after 10 mammograms was estimated to be 49 percent.”

    Furthermore, “The proportion of false-positive results that lead to biopsy varies substantially in different settings. In screening trials, 1 percent to 6 percent of all women screened underwent biopsy, and the proportion of biopsies that revealed cancer ranged from 12 percent to 78 percent.”

    So, “The consequences of false-positive mammograms are uncertain. Most, but not all, studies report increased anxiety from an abnormal mammogram.”

    All that said, I, and most of the patients I’ve talked to about this issue, agree with the USPSTF when it adds, “At the same time, some studies report that women in the United States may be willing to accept a relatively high number of false-positive results in the population in return for the benefits of mammography.”

    This is why I think most women, after considering these issues, and talking with their physicians, will continue to choose to have screening mammograms.

    However, as I mention in my post above, there is another factor to consider.

    The USPSTF says, “Some experts view the over-diagnosis and treatment of ductal carcinoma in situ (DCIS) as a potential adverse consequence of mammography. Although the natural history of DCIS is variable, many women in the United States are treated aggressively with mastectomy or lumpectomy and radiation. Given the dramatic increase in the incidence of DCIS in the past two decades (750 percent) and autopsy series suggesting that there is a significant pool of DCIS among women who die of other causes, screening may be increasing the number of women undergoing treatment for lesions that might not pose a threat to their health.”

    This, to me, is a huge concern.

    One last thought from the USPSFT: “A final potential concern about mammography is radiation-induced breast cancer, but there are few data to directly assess this risk. A 1997 review, using risk estimates provided by the Biological Effects of Ionizing Radiation report of the National Academy of Sciences, estimated that annual mammography of 100,000 women for 10 consecutive years beginning at age 40 would result in up to 8 radiation-induced breast cancer deaths.”

    Therefore, this is not a huge risk, but worth considering.

    Hope this helps.

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