17 January 2016

In October 2015, the American Cancer Society (ACS) updated their screening mammography guidelines, raising a lot of questions and concerns as annual mammograms were no longer recommended for all women starting at age 40. The United States Preventative Services Task Force (USPSTF) released new guidelines on screening mammography last week. The new USPSTF guidelines recommend an individualized risk-based approach for women age 40-49, and mammographic screening every other year for women age 50-74. The task force acknowledged that screening mammography reduces the likelihood of dying from breast cancer, but noted that the benefit was the greatest for women age 60-69, and the benefit was small for women age 40-49. For younger women, they noted that screening mammography is associated with higher false positives (false alarms).

The conflicting guidelines published by the USPSTF, ACS, and other organizations have caused much confusion. Many women simply want to know what they should do. The reality is, screening mammography is a one size fits all tool, and as any woman knows, that doesn’t really work. The sensitivity (“effectiveness”) of mammograms will vary depending on a patient’s age, menstrual status, use of hormone therapy, body mass index, breast density, and other factors. It is unrealistic to expect that one test can account for all of those variables, as well as personal risk factors for breast cancer, and personal preferences regarding screening risks and benefits.

To state it very simply:

  • Mammograms may lead to improved survival from breast cancer by detecting some cancers early
  • Some breast cancers are so aggressive that early detection does not lead to improved survival
  • Mammograms are imperfect

It is important to note that the USPSTF and ACS recommendations apply to average risk women. Unfortunately, risk assessment is not routinely performed, and many factors associated with an increased risk, such as heavy alcohol intake and breast density, are not taken into account in the existing models. In an ideal world, we would swab a cheek, obtain some DNA, and then determine whether or not a woman is predisposed to develop breast cancer [I’m thinking beyond BRCA and other genetic testing here]. If we can determine that a 30 year old woman, even without a family of breast cancer, is predisposed to develop the disease, we can make educated screening recommendations (perhaps ultrasound and/or MRI, as mammograms are not very helpful in very young women).  If we can determine that a woman is highly likely to die of a heart attack by age 60, and has no cancer predisposition, she might make the decision to forego screening mammography. Unfortunately we’re not quite there yet, but there are genetic risk tests under development.

I recently spoke with a researcher specializing in cancer risk. We discussed that at the end of the day, multiple organizations will continue to look at the evidence and draw different conclusions, so in his opinion, it wasn’t realistic that we should expect consensus. Physicians, researchers, and organizations are currently spending a lot of time and effort arguing with each other about whether mammography should start at age 40, if mammograms should be performed every versus every other year, and when screening should stop. However, our time and efforts might be better spent by working together to address issues such as disparities in access to screening mammography and lack of access to quality mammography and breast care for many women.

Recognizing the variability of each woman and her breasts, acknowledging the uncertainties regarding the risks and benefits of screening, and focusing on a shared decision making approach might help reduce some of the confusion. In medicine, as in many areas in life, there is often more than one right answer. The same applies to screening mammography. Time to move beyond the one size fits all approach.

Additional Reading:
New York Times: Panel Reasserts Mammogram Advice
JAMA: A Public Health Framework for Screening Mammography: Evidence-Based vs Politically Mandated Care 
New York Times: Insurer Rewards Push Women Towards Mammograms
Forbes: A Turning Point in the Breast Cancer Screening Debate?
NPR Shots: Federal Panel Finalizes Mammogram Advice That Stirred Controversy
OncLive Final USPSTF Guidelines
Cornell Mammogram Decision Aid for Women age 40-49

25 October 2015

The American Cancer Society has issued new guidelines for screening mammography, and they are sparking a lot of discussion. Previous guidelines, which have been in place since 2003, have recommended:

  • Annual mammography beginning at age 40 and continuing for as long as a woman is in good health
  • Clinical breast exam (CBE) [exam by a physician] about every 3 years for women in their 20’s and 30’s, and every year for women 40 and over
  • Women should know how their breasts normally look and feel and report any breast changes to a health care provider right away. Breast self-exam (BSE) is an option for women starting in their 20’s.

The current guidelines recommend:

  • Women should undergo regular screening mammography starting at age 45
  • Women 45 to 54 years of age should be screened annually
  • Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually
  • Women should have the opportunity to begin annual screening between the ages of 40 and 44 years
  • Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer
  • Clinical breast exam is not recommended for breast cancer screening among average risk women of any age

The full study was published in the Journal of the American Medical Association. These guidelines seem to be a drastic change, but they are based on careful evaluation of the available literature. They are also more in line with the US Preventative Services Task Force recommendations for breast cancer screening (which are in the process of being updated). Mammograms certainly are of benefit in terms of early detection. However, as we have gained a better understanding of the importance of tumor biology, the mantra “early detection saves lives” does not hold true for all.

As stated on the American Cancer Society website, “The goal of screening mammograms is to find breast cancer early, when treatment is more likely to be successful. But mammograms aren’t perfect, and they do have risks. Sometimes mammograms find something suspicious that turns out to be harmless, but must be checked out through more tests that also carry risks including pain, anxiety, and other side effects.” I disagree with using anxiety as a reason to limit screening recommendations. While some women do experience significant anxiety related to mammography callbacks, proper pre-mammogram counseling should help alleviate some of the worry. As Dr. Elaine Schattner noted in her piece published in Forbes, “concern about fear or anxiety should not form the basis of any screening recommendations”.

These guidelines apply to “average risk” women. But given that ANY woman (and any man) may develop breast cancer, what does “average risk” mean? The first part of risk assessment should be a careful history, including a careful and detailed family history. While most realize that a having a family history of breast cancer increases their risk, fewer understand that family history of other cancers, including ovarian, colon and pancreatic cancers may be “hereditary red flags”, and genetic counseling and testing might be indicated. There are several risk assessment models which can and should be used by physicians on a routine basis. Newer forms of risk assessment which include evaluations of small variations in an individual’s DNA may provide a more personalized risk assessment. The contribution of breast density as well as lifestyle factors such as weight, level of activity, and alcohol intake need to be considered. The North Shore – LIH Health System and Bright Pink both have helpful risk assessment tools.

Mammography has never been a perfect screening test. It has significant limitations in young women and those with dense breast tissue, and in older women it may find more than it needs to. We have a “one size fits all” test, and women and their breasts are most certainly NOT “one size fits all”. The decision when to begin screening and how often to be screened is now a shared decision, between a patient and her physician. Decision support tools, such as Weill Cornell Medical College’s Breast Screening Decisions program, can help women sort through the conflicting information and make a decision that is right for them.

While guidelines can be helpful in making recommendations for populations, the ideal screening method for the individual remains to be seen. For screening mammography to truly be of benefit, we need to determine who is at risk and then decide what imaging modality is most appropriate for that individual woman. We also need to know which lesions, once detected, can safely be ignored. We know where we need to be. Now the science and technology needs to catch up.

Additional information:
New Guidelines for Breast Cancer Screening in US Women – JAMA Editorial
Science Won’t Settle the Mammogram Debate
Stat News: New Guidelines Urge Later, Less Frequent Mammograms
Mammography Guidelines Revisited – Lori Marx Rubiner