Inaccurate Claims about the Unequivocal Benefit of Early Detection Persist Despite Evidence to the Contrary.

When Dr. Susan Love was updating the 2015 edition of her Breast Book for a chapter titled, “When Cancer Comes Back,” she asked women with metastatic (stage IV) breast cancer what they wished the public knew about this disease. Many replied that, “the ‘early detection’ of an invasive cancer through [mammography] screening does not guarantee you will not get metastatic disease.”[1] Why the emphasis? Those women were pointing to no guarantees from early detection strategies.

Accurate information about the benefits of screening an entire population of women for breast cancer is missing from most awareness campaigns. Yet it’s something women with recurrences know firsthand, and what many experienced researchers have said for years.

The Most Studied Screening Tool Ever

The most reliable way to estimate the effectiveness of screening for reducing mortality is with randomized trials. Knowing this, Drs. Peter C. Gotzsche and Karsten J. Jørgensen scrutinized existing studies of screening to determine their accuracy. In a systematic review published in 2000, they reported on the research designs and findings of seven screening trials involving more than 600,000 women who were randomly assigned to receive screening mammograms or not. What they found was that poor research designs led to the questionable results. Whereas the less carefully done studies found a reduction in breast cancer mortality among screened women, the best designed studies found little or no benefit.

These studies taken in combination suggest that mammo-screening, at best, could improve the relative death rate (i.e., the screened groups studied relative to the unscreened groups) by 10 or 15 percent. That is, for every 2000 women invited for screening throughout 10 years, one could avoid dying of breast cancer. In absolute terms, the reduction in mortality due to mammo-screening remains miniscule. In addition, the effect of screening on all-cause mortality (or, the lethal complications of cancer treatments typically ascribed to ‘other causes’ in addition to breast cancer) erases any mortality benefit from mammo-screening. This crucial insight emerged when insufficient documentation across studies was corrected. Add to that, a more recent recognition that screening also creates harms including overdiagnosis and overtreatment from surgery, radiation, and adjuvant drugs — for far more than those helped against breast cancer.

Find more analyses of screening studies here ».

The Screening Engine Keeps On Churning

clarityinfographic-cropIn view of the most reliable evidence, the promise of early detection via screening mammograms to ‘save lives’ is a lie. [2] Why, then, do we still see claims about the overwhelming benefits of mammogram screening?

Consider this PR pitch from Solis Women’s Health, a limited liability corporation that owns and operates a network of breast screening and diagnostic centers in Arizona, North Carolina, Ohio, and Texas. A 2016 email blitz from Dallas-based TrizCom Public Relations, on behalf of Solis, headlined some strong and poorly substantiated claims:

“Mammography Saves Lives—National Women’s Health Week 5/8-5/14—Experts from Solis Mammography Share the Importance of Early Detection with Original Infographic.” [3]

The pitch piggybacked onto National Women’s Health Week (NWHW), a sound initiative from the U.S. Office on Women’s Health that promotes exercise, healthy eating, safety, mental health, and a variety of so-called preventive screenings that include mammograms. [4] But whereas the NWHW’s website acknowledges “problems with mammograms” that include exposure to radiation, the risks of false positives and false negatives, the incompleteness of screening as a stand-alone test, and the important caveat that, “finding cancer does not always mean saving lives,” Solis avoids all of this to focus the reader’s attention on factoids and misinformation.

Solis Mammography’s [Fast and Loose] Facts

To lend credibility to its claims, the PR pitch cited four “Fast facts” from the American Cancer Society’s “2015 – 2016 Breast Cancer Facts & Figures.”

  1. In 2015, 231,840 women were diagnosed with invasive breast cancer and of that, 46,350 (20 percent) were diagnosed under the age of 50.
  2. Mammography is the single most effective method of early detection since it can often identify cancer several years before physical symptoms develop.
  3. The decrease in breast cancer-related deaths over the past two decades is almost entirely attributed to mammography detection.
  4. The 5-year survival rate is 100 percent for women diagnosed with stage 0 and stage 1 breast cancer.” (My emphasis added.)

Fact-Checking the ‘Facts’

Fact 1 is technically correct, but what do the figures really mean?

Breast cancer is the most commonly diagnosed cancer among women, excluding skin cancer. Incidence rates continue to rise. A woman’s lifetime risk of breast cancer diagnosis is 12.3 percent, or 1 in 8, and that risk was just 1 in 11 in the 1970s. Breast cancer risk increases with age, and the median age at diagnosis is 61. In other words, there is a lot of breast cancer and older women are at greater risk.

What does the “under the age of 50” reference really point to then?

In 2002, U.S. government agencies began shifting mammography screening protocols to reflect new research. Most recently, the U.S. Preventive Services Task Force updated its recommendations: “biennial screening mammography for women 50-74 years.” [5] The recommendation, based on moderate evidence of benefit, flies in the face of traditional protocols that recommended screening women every year beginning at age 40. Radiologists and breast imaging centers accustomed to testing women in that age group face sizable losses in revenue if women heed the advice. If women over age 50 do the same and get screened every other year instead of annually, the losses are substantially higher. And if women know that that the current evidence on high-tech digital mammography is insufficient to recommend it as a better alternative to traditional mammograms, that too will be a challenge to the forecasted growth rates of the medical imaging industry, one that is estimated to reach $33.42 billion by 2020.

Fact 2 is mostly correct. Mammography X-rays can find cancers before a lump can be felt, though mammograms miss about 10 percent of breast cancers. The underlying narrative that ‘early detection’ via mammography translates to more lives saved is another story.

First, not all cancers are the same. Some are slow and would never end up causing symptoms in a person’s lifetime (so they don’t really need to be found with screening). Others are more aggressive and, if found before they spread to other parts of the body, can be contained with treatment. Still others are so aggressive that regardless of when or how they are found, they are already on a deadly path. Mammography is excellent at finding those indolent cancer cells. But it misses about 10 percent of invasive cancers, often those that are faster growing and more deadly. Thus, screening mammograms increase overtreatment.

Second, if the theory about early detection were correct, that “every breast cancer is curable as long as you catch it in time,” then finding and treating more “early” cancers would lead to fewer cases of advanced disease, and significantly decrease mortality. This has not been the case. Some 20 to 30 percent of breast cancers come back (15 years or longer) after the successful completion of treatment. The average number of breast cancer deaths per year, hovering at 40,000 for women, has not changed in decades. Yet, mammography is often described as the best tool we have, without explaining its shortcomings.

Fact 3 that mammography screening is responsible for the decline in breast cancer deaths over the past 20 years is incorrect.

Despite the steady number of deaths each year from breast cancer, the overall mortality rate has declined over the last three decades. A study of 30 years of breast cancer data published in the New England Journal of Medicine found that screening itself has had only a marginal effect on the breast cancer death rate. Corroborating findings from other studies, the researchers concluded that, “the good news in breast cancer — decreasing mortality — must largely be the result of improved treatment, not screening.” They also find that one-third of all newly diagnosed breast cancers are the result of overdiagnosis (detecting cancers that would never become life-threatening or cause symptoms). Even the American Cancer Society, a long-time proponent of mammograms, has acknowledged the persuasive evidence that improvements in treatments, not screening, account for most of the recent mortality decline. [6] Solis ignores this fact to pump up its claims about the benefits of screening mammograms.

Fact 4 that 100 percent of women diagnosed with stage 0 and stage 1 breast cancers are alive after five years is correct but irrelevant, and therefore misleading.

Lumping together a pre-cancer confined to the breast (stage 0) with an invasive cancer that has the capacity to spread (stage 1) combines apples and oranges, artificially inflating survival statistics to support the alleged benefits of early detection via screening mammograms. Breast cancer charity Susan G. Komen for the Cure was criticized in 2012 for misleading the public with similar claims. Researchers argued that, “there is a big mismatch between the strength of evidence in support of screening and the strength of Komen’s advocacy for it.” At issue was an advertising campaign suggesting that screening is the key to surviving breast cancer. Like Solis, the accompanying website shared rosy survival statistics as evidence to support the claim. These, too, were taken out of context. “Early detection” does nothing to improve long-term survival for women with metastasized disease.

Adding to the Confusion, with an Infographic

The PR pitch with its partial facts and inaccuracies foreground Solis’s primary deliverable, an infographic casting updated screening guidelines as confusing simply because they conflict with the old, preferred ones, the ones that keep customers flocking in for their state-of-the-art, but increasingly problematic, breast x-rays.

The infographic titled, “Confusion vs. Clarity, capitalizes on an ongoing turf war—promoted largely by the radiology profession–about the evidence-based recommendations to do fewer mammograms. Echoing a website sponsored by the American College of Radiology that headlines with, “Mammography Saves Lives…one of them may be yours,”and calls to “END THE CONFUSION,” Solis and colleagues show their true colors. Instead of promoting evidence-based protocols, these groups are actually promoting fear, stating that, “The danger [from the confusion] is the risk to a woman’s life.”

In concert with messaging on the infographic which states, “Mammograms are knowledge. Knowledge is power,” the real story is that this billion-dollar industry co-opted the language of empowerment because it can’t keep pace with an overwhelming body of evidence that has the capacity to deflate its bottom line.

 

End Notes and Additional References

[1] Susan M. Love, Dr. Susan Love’s Breast Book, 6th Edition (Boston: Da Capo Press, 2015), 509.

[2] See www.thennt.com on mammogram screening for a succinct summary.

[3] E-mail from Jo Trizia to Gayle Sulik, April 22, 2016, “SUBJECT: Mammography Saves Lives—National Women’s Health Week 5/8-5/14—Experts from Solis Mammography Share the Importance of Early Detection with Original Infographic.” Also at http://newsroom.solismammo.com/2016/02/29/what-the-facts-are-saying/.

[4] U.S. Department of Health and Human Services. http://womenshealth.gov/screening-tests-and-vaccines/screening-tests-for-women/#tests.

[5] Average risk does not include women with a strong family history or known mutations. By 2009 there was enough evidence on women in their 40s to show that harms from excessive false positives outweighed the small, if any, survival benefit. USPSTF 2009.  (U.S.) Department of Health and Human Services Office of Women’s Health, 2016, www.womenshealth.gov. See BCC, Bonnie Spanier, “What We Can Learn from New ACS Guidelines on Screening Mammography,” December 22, 2015.

[6] ACS Facts & Figures changed in 2015-2016: “The decline in breast cancer mortality has been attributed to both improvements in breast cancer treatment and early detection.” (page 8).  Mette Kalager, Hans-Olov Adami, Michael Bretthauer, “Too much mammography,” BMJ 2014;348:g1403 doi: 10.1136/bmj.g1403. Mette Kalager, Marvin Zelen, Froydis Langmark, Hans-Olov Adami, “Effect of Screening Mammography on Breast Cancer Mortality in Norway,” New Eng J Med 2010;363:1203-1210.

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