Screening Mammography

Filtering out the noise

Roughly one in eight women will get some sort of breast cancer during their life, but only about 20% of those will have any identifiable risk factors. Screening for breast cancer has therefore been and continues to be an essential part of care for anyone who has breasts (usually women, but not always . . . for convenience only I will reference just women) but, in my 40+ years of specialty practice, best practice has never been quite settled. One group’s recently updated guidelines have made headlines, though the changes are not really new, having been available in proposed draft form for a year but now finalized. It has been a popular discussion topic but let me try to cut through the noise and outline the important points and my personal methodology and insights.

• In the absence of specific risk factors, my personal recommendation, that I have modified little over the years, is to begin annual mammograms at age 40, get a supplemental breast ultrasound if the breasts are dense, and continue until one’s remaining life expectancy is less than ten years (conventionally considered to be age 75).

• Recommended guidelines establish the standard for the advice that providers are expected to offer and document. Not following them could lead to liability risks and could be considered medical misconduct by a state licensing board. However, individuals may still choose not to follow the provider’s advice for valid reasons specific to their situation and preferences ("shared decision making"). The USPSTF moved up their recommended age for screening after observing increased rates of breast cancer in younger women, black women in particular, which outweighed their previous concerns about false negatives and unnecessary procedures. These concerns might still convince women to defer testing:

  • It is probable (greater than a 50% chance) there will be a false positive report at some point. Many of those will be resolved with just additional studies and closer follow up, but roughly 10 to 20% will require a biopsy. If a biopsy is necessary, an open biopsy might be necessary but usually minimally invasive needle biopsies or core biopsies (essentially a very large bore needle that can possibly remove the entire area of concern) can be done under X-ray, ultrasound, or MRI guidance.

  • Some not uncommon cancers (pre-cancers?) are not aggressive and might never cause a problem, even with no treatment, and an earlier diagnosis is not beneficial. Life as a cancer patient can be extremely stressful and minimizing that, when an earlier diagnosis makes no difference, is attractive.

  • Mammograms can be uncomfortable. Really uncomfortable.

  • The process is unavoidably anxiety provoking, especially when tests are positive (false or otherwise). Some people don’t manage anxiety well.

• If anyone feels a breast lump, they need a diagnostic and not a screening procedure. If you definitely feel something do not be put off because a particular clinician doesn’t detect anything. Do not accept an opinion that a lump is not cancer based on just the physical exam. A tender lump is admittedly very unlikely to be cancer, and might go away with the next period, and a lump that suddenly appears may be a cyst only (and could also go away or resolve with aspiration), but anything that persists needs to be investigated further. Depending on circumstances this could be a mammogram, a breast ultrasound (a “sonogram”), or a breast MRI, and the most definitive treatment would be a biopsy. Finally, a palpable lump should still be biopsied even if the mammogram/ultrasound/MRI are all negative.

• Like conventional photography, digital imaging has replaced traditional analogue imaging, and film and light boxes have been replaced by large computer monitors. Digital breast tomosynthesis (DBT or “3-D mammography”) can be done at a cost and radiation exposure (about the same as flying cross country) comparable to the older analogue technology. The quality and clarity of the images are definitely superior and these days all mammograms should use DBT whenever possible.

• Since I first started in practice, breast cancer management has become much less frightening to contemplate and therefore less of a deterrent to appropriate screening. Standard treatment then was very disfiguring, consisting of radical removal of the breasts along with underlying muscles and multiple lymph nodes, then possibly followed by wide field radiation and/or systemic nonspecific chemotherapy. Surgery has improved, radiation treatment has become much more focused and precise, chemotherapy is more targeted and selective. Primary treatment may only require removal of the lump, and mastectomies when indicated are more limited. Reconstructive breast surgery, if desired, is standard and often started at the time of mastectomy, with results that are remarkably normal appearing and natural feeling.

• Breast screening guidelines are published by:

  • The United States Preventive Services Task Force (USPSTF) “is an independent, volunteer panel of national experts in prevention and evidence-based medicine” created in 1984 to “make evidence-based recommendations on effective ways to prevent disease and prolong life.” Draft recommendations are published for comment about a year in advance of being finalized.

  • The American Cancer Society (ACS) was established in 1913 and is “a nationwide nonprofit organization dedicated to eliminating cancer.”

  • The National Comprehensive Cancer Network (NCCN) is “a not-for-profit alliance of 33 leading cancer centers,” originally formed in 1995 with nineteen centers.

  • The American College of Obstetricians and Gynecologists (ACOG) was founded in 1951 and “is the premier membership organization for obstetrician-gynecologists.” I am a Life Fellow member of ACOG.

  NCCN guidelines are the most conservative/aggressive, followed generally by the ACS, ACOG, and USPSTF. All of the different guidelines agree that, in the absence of additional risk factors, starting at least by age 45 mammograms should be done at least every other year through age 74. You will be following someone’s guidelines if screening mammograms are started anytime between age 40 and 45 and continued either once a year or every other year after that. Before the recent USPSTF finalized guidelines the consensus starting age for screening was 50. Over the years I often had women tell me that they felt their risk was low because “breast cancer was not in the family.” This is a misconception. As mentioned at the beginning, there will be no prior identifiable risk factors 80% of the time. High risk individuals, based on family history or on risk calculators like the Gail Model, will need an individualized plan and may need to start screening as early as age 25. Diagnostic or screening studies performed before age 40 generally should be a breast ultrasound or breast MRI. Breasts are more dense in younger women, making mammography interpretation more difficult and much less useful because the density gives a more uniform white appearance which obscures detail.

In summary, at the end of the day it is a numbers game for those who determine the guidelines, and most women without risk factors are not ultimately going to detect a breast cancer during a routine screening mammogram. However, the risks of screening seem small (at least to this old white guy). Screening mammography will detect some cancers, and screening beginning at age 40, rather than 50, could save an additional one or two lives per thousand women. It seems a better choice to start earlier and potentially detect an early and more easily treated cancer rather than wait and possibly detect it when it is more advanced and harder to treat, albeit still successfully.