ACS Defends Their Breast Cancer Screening Guidelines

American Cancer Society Responds to Expert Opinions on the Breast Cancer Screening Guidelines

breast cancer screening guidelinesThe American Cancer Society recently released their Guidelines for the Early Detection of Breast Cancer. Women look to this as their essential guide to detecting breast cancer early on. After much controversy surrounding these new guidelines in the breast cancer community, the world leading expert in mammography Dr. Laszlo Tabar spoke with us to share his concerns with the public.

The American Cancer Society (ACS) responded to Dr. Laszlo Tabar‘s article and wanted to set the record straight. There are two sides to every opinion regarding these Early Detection Screening Guidelines. What are your thoughts? You be the judge.

Below is the American Cancer Society’s response.

BCA: The American Cancer Society has been considered as one of the most respected and influential groups in breast cancer, and many people look to ACS as a guide for the standard of breast cancer early detection and prevention. But recently, they released new screening guidelines that have cause a lot of controversy in the breast cancer community.

Unfortunately ACS has angered many breast cancer survivors and experts by recommending that women should start getting mammograms at 45 instead of 40, and that everyone can skip the routine manual breast checks by doctors. They have also implied that less screening for breast cancer is better than more.

ACS: The ACS Guideline Development Group (GDG) focused on the long standing debate about the age to begin screening. We decided early in the process to look not only at the data in the traditional 10-year age groups (30-39, 40-49, or 40-49 vs. 50+) but also to carefully examine various measures of disease burden in 1-year and 5-year age groups. Two points are important.

First, we concluded that starting screening at age 50 was not supportable when the benefit of screening and the burden of disease are comparable between the 22 million women who are 45-49 and 50-54. Further, we concluded that the risk of breast cancer from ages 40-44 was sufficiently low, especially in the very early 40s, that women should have the option to start screening  at 40, or wait until age 41, 42, etc. or age 45.

In the coming year, about 9 out of 10,000 women aged 40 in the U.S. will be diagnosed with breast cancer. This is similar to the 8 in 10,000 women aged 39 who will be diagnosed with breast cancer. The proportion of 40-year old women who will be worked up for a suspicious finding in U.S. imaging centers is greater than 10% on the first mammogram (or over 1000 in 10,000 women). This proportion of false positive findings is similar for women age 40 and age 45, but at age 40, the risk of disease is much lower.

We concluded that in an era when there is a greater emphasis on benefits and harms, women need to consider both positive and negative aspects so they can make an informed decision about when to start screening. Many women will make the decision to start screening at age 40, and the new ACS guideline supports that informed choice. And, by age 45, ACS strongly recommends that all women should be undergoing annual screening.

Second, the ACS did not imply that less screening for breast cancer is better. In fact, we supported the recommendation for annual screening for women ages 40-54 with new evidence from a study commissioned by ACS and published on the same day in JAMA Oncology showing that pre-menopausal women screened every 24 months were at significantly higher risk of being diagnosed with an advanced breast cancer.

This finding is consistent with the important conclusions about age and sojourn time observed in the Two County Trial.  For post-menopausal women, there was no significant difference in the advanced cancer rate with biennial screening vs. annual screening. This element of the new guideline received no attention from the media.  While the ACS guideline recommends that women transition to biennial screening at age 55, it also recommends that they retain the option to be screened every year, since annual screening at any age is associated with some additional benefit, but also an additional chance of being recalled.  Some women may choose to keep screening each year until the age of 60 or 65, but at some point from age 55 onward biennial screening will make sense.

Again, the recommendation provides women with a guideline based on the evidence, but we also allow for women to choose to continue with annual screening.  Finally, regardless how one feels intuitively about clinical breast examination, or personal experience, there is little supporting evidence to continue including this examination as part of the screening recommendation, although we expect many clinicians will recommend to their patients that they undergo annual palpation, and this has to be judged as acceptable within the doctor/patient relationship.

BCA: But with recent scientific evidence proving that breast cancer is affecting more women at a younger age, why have they pushed the recommended age limit up to 45? Unfortunately, this isn’t the only concern breast cancer experts have about these new guidelines.

ACS: ACS did not “push” the age limit to 45 (see above). Further, ACS did not see evidence that that there is a significant increase in the incidence in young women. In the U.S., between 1992 and 2012, the breast cancer incidence rate in women under age 50 increased from 43.1 to 43.8, less than 1 case per 100,000 women.  A more relevant number might be the rate for women ages 35-49 in the recent time period, which increased about 4 cases per 100,000 over the past decade (from 2001 to 2012), although rates are down 2 per 100,000 since 2007. The incidence rate is important at any age, but the statement above suggests a large change in rates, which we are not seeing.

Tabar: Dr. Laszlo Tabar’s Response to the American Cancer Society Breast Screening Guidelines

“On the positive side, I would like to mention that the ACS guidelines are in line with the American Cancer Society’s several decades long support for early detection of breast cancer using high quality mammography screening. There are at least two important components that need to be on place for successful breast imaging that leads to detection of breast cancer in a significantly earlier phase.

1) The quality of the mammography examinations, that, fortunately does not vary from breast center-to-breast center as much as it used to vary when screen-film mammography was used. The introduction of digital mammography has evened out the differences, so high quality mammography is provided in the vast majority of breast centers.

2) The problem lies in the considerable variation in the quality of interpreting mammograms. Therefore, I would have liked to see that the American Cancer Society strongly recommends regular training and retraining of all categories of professionals involved in mammography screening. This includes the technologists, nurses, and the physicians. As I see it, most of the issues debated today (“harm”) would not be headlines if the interpretation of the mammograms and management of the findings varied less among the providers.

ACS: We acknowledge the many and substantial contributions that Dr. Tabar has made in the field of breast cancer screening and appreciate the opportunity to clarify some misconceptions. Dr. Tabar’s points 1 & 2 are on target, and we agree completely with the importance of quality assurance programs that go beyond MQSA’s requirements. In the JAMA report, the guideline states, “Improving access to high-quality breast imaging remains a priority.”  A

CS did not go beyond that, given the challenge to stay within word limits, and recommending improved interpretive skills is not directly related to the screening guideline. However, it is critically important, and the ACS agrees that the experience of so-called harms could be measurably reduced by improved accuracy, and more effective communication to women about what to expect when they undergo screening.

Over the past 25 years the ACS has devoted considerable resources to advocacy and research for high quality mammography, in particular addressing point 2, the importance of improving interpretative skills. ACS has spent several million dollars over the past decade to develop a better understanding of factors associated with interpretive accuracy and how interpretive skills can be improved. The results of this research were recently highlighted in a meeting at the Institute of Medicine in Washington, D.C. Below is a link to the meeting announcement, and a link to the summary report.

Sources

http://iom.nationalacademies.org/Activities/Disease/NCPF/2015-MAY-12.aspx

http://iom.nationalacademies.org/Reports/2015/Assessing-and-Improving-the-Interpretation-of-Breast-Images.aspx?utm_source=IOM+Email+List&utm_campaign=2c51d65293-IOM_News_September15&utm_medium=email&utm_term=0_211686812e-2c51d65293-180216449

Tabar: In my personal opinion, there are two points where the guidelines should have done a better job. Since it did not, that resulting strong reaction among the physicians is understandable:

  1. Recommendation of the lower age limit for screening. Unfortunately, more and more young women are getting breast cancer; the disease is creeping down in age and at the same time, there is a massive scientific evidence for starting screening at age 40:

ACS: The disease burden issue is addressed above. The GDG  concluded that there is strong evidence of the benefit of screening in women ages 40-49, based on age at randomization, age at invitation, and age at exposure to screening, while there is less evidence of the benefit of starting screening at age 40. These data principally are limited to the SCRY study, and the UK Age Trial. The new recommendations acknowledge the benefit. They make a distinction between recommending that everyone should be screened from age 40 onward vs. everyone should have an opportunity to start screening at age 40.

Tabar: The SCRY Study carried out in the entire country of Sweden. This study found that breast cancer death was 29% lower among 40-49 year old women who attended mammography screening regularly. This result was observed above and beyond the benefit of using modern therapeutic regimens.

ACS: We agree, but the benefit was greater in women exposed to screening between ages 45-49 (32%) vs. 40-44 (18%). This was noted in the guideline, but did not influence the recommendation for informed decisions at age 40.

Tabar: The recently published nationwide breast screening study in Canada proved a 40% decrease in mortality starting at age 40.

ACS: The Pan-Canadian trial was based on age at entry into screening at any age within the intervals that were compared.

Tabar: The WHO’s International Agency for Research on Cancer (IARC) has published the view of 23 experts from 16 different countries in the New England Journal of Medicine. They recommended starting mammography screening at age 40.

ACS: In the 2015 NEJM summary of the soon to be published update of the Handbook on Breast Cancer Screening, IARC did not issue recommendations, but rather issued judgements about the degree to which benefits of screening exceed harms. The Committee concluded that there was sufficient evidence to conclude that benefits exceeded harms for women 50-69 and 70-74, but only limited evidence for 40-44 and 45-49. For ages 45-49, a footnote was appropriate, stating, “The majority of the voting members of the IARC Working Group considered the evidence as limited; however, the vote was almost evenly divided between limited and sufficient evidence.”

Tabar: The Age trial in the UK showed a 15% mortality reduction in women aged 40-49.

So my question is: Why has the American Cancer Society not taken these recent publications into account when recommending about the lower age limit? Instead, they diligently emphasized the limitations of mammography in younger women and also used the term ‘harm’, a term I strongly dislike. We all know that mammography has its limitations in women with dense breast tissue. We have a solution to compensate for this limitation: the use of multi-modality approach to screen younger women and women with dense breasts in any age. The recommendation should have therefore suggested the use of an additional examination method to digital mammography, such as e.g. automated breast ultrasound to compensate for the flaws of mammography.

ACS: We feel this is a misinterpretation of the guideline statement. The ACS update stands apart from all other guideline statements in highlighting the limitations of the RCT evidence, and emphasizing the benefit observed in studies of modern, population-based mammography screening. It is not correct to say that we “diligently emphasized” the limitations of mammography in younger women. ACS simply stated that at a time when risk and cancer detection rate was lower (less than 1 in 1,000 women will be diagnosed at age 40), and recall rates were higher (close to 1 in 5), that women should have an opportunity to choose to begin screening at age 40, at some age before age 45, or at age 45, when ACS strongly recommends that they should be undergoing annual screening.

The recommendation allows flexibility; nothing in the discussion implies that we would discourage the decision to begin at age 40. As for supplemental imaging, among Dr. Tabar’s many important contributions to breast cancer screening, data on the value of supplemental imaging for women with dense breasts is an important, recent contribution. ACS now is initiating an update of screening recommendations for high risk women, and mammographic breast density will be included in the review.

Tabar: I had strong feelings when I realized that the ACS does not recommend clinical breast examination for breast cancer screening among average risk women at any age, since it was immediately interpreted as if they did not recommend physical examination of the breasts in the offices of the gynecologists and general practitioners. I reacted on this point because physicians should not be told to eliminate such a basic medical practice and principle; also, in quite many countries this could be the only means leading to improved breast care and better outcome of the breast cancer patients.

ACS: Mammography is the single best method for detecting breast cancer before it is palpable and likely has worse prognosis than if it were detected when it was occult. The GDG examined the evidence carefully and did not find any evidence to support routine clinical breast examination in addition to mammography in women ages 40 and older, nor did we find evidence supporting the use of clinical breast examination for younger women. Some doctors and nurses perform this exam with great competence; however, most do not, devoting too little time to the exam and having poor technique. For decades efforts have been devoted to improve the quality of CBE, and they have not proved effective. This may be one reason why the data reveal so little benefit.  We expect many doctors will continue to recommend and provide this examination to their patients.

Tabar: Many of us have the impression that those that wrote these recommendations looked a little too much to the left and to the right, i.e. they were looking at the US Task Force and other organization’s recommendation. There seem to have been a bit too much politics involved. The American Cancer Society might have lost some of its good reputation through publishing the current guidelines. It is unfortunate if that is the case. Hopefully, the debate that follows, will help us to arrive at practical solutions that will serve women better.”

ACS: The ACS expected that the new guideline would be controversial. However, ACS also expected that it would have received very careful scrutiny by those who are familiar with the evidence, particularly in terms of interpretation of the age-specific recommendations. In this update, the committee firmly endorsed the importance of observational studies. The careful review of disease burden, benefit, and adverse outcomes is so similar in women ages 45-49 and 50-54 that it calls into question the rationale for guidelines that endorse screening beginning at age 50. The burden of disease, the benefit of mammography, and the benefit/harm ratio (we as well appreciate the problems with the term “harms”) show that the 11 million U.S. women ages 45-49 are very similar to the 11 million women ages 50-54. We also affirmed the benefit of annual screening, but provided new empirical evidence that the benefit was principally important for women who are premenopausal. Going forward we’ll be able to more clearly identify post-menopausal women who also should vs. may elect to continue annual screening, most likely women with significant mammographic breast density and women with a family history.

Our interest here is to clarify some points of misunderstanding in the new ACS guideline. We welcome feedback about the guideline and are hope to bring greater clarity to the recommendations. We are committed to implementing practical solutions.