11 Jun 2016

Mammograms - To the doubters

Mammograms – some questions answered.

 

I would like to address some of the arguments against having a screening mammogram that have been brought up in the comments to my article on mammography and radiation.

What follows is a very long essay and for that I apologize. I feel passionately that every woman with breast cancer deserves the opportunity to have it picked up early and in time to receive life saving treatment, hence the essay ..

 

  1. Mammograms don’t actually reduce cancer deaths: Without doubt the topic of screening mammography is contentious and has doctors and patients on both sides of the debate. However, the vast majority of trials confirm reduction in mortality (death) from breast cancer on account of screening programs. Yes, there are some famous trials that did not show this, most notably in Canada and Sweden. It has been demonstrated though that these trials were seriously flawed for a number of reasons, not least of which is that they were conducted at least 20 years ago with old technology1. The new digital mammogram machines (including 3D mammograms) are far superior at identifying cancers. More recent trials reinforce the fact that mammogram screening improves mortality between 20 and 40%2,3,4,5
  2. Mammogram screening results in over-diagnosis. The theory here is that mammograms pick up slow growing cancers that may never be problematic and as such, patients are subjected to surgery and chemotherapy that they don’t need. With regards to DCIS (ductal carcinoma in situ), a pre-cancerous condition which is only visible as tiny microcalcification on mammograms, it is true that we cannot distinguish the dangerous(high grade) from the non dangerous(low grade). A high grade DCIS is a very aggressive condition that can kill a person faster than many solid cancers. The only way to know which you have, is by way of a biopsy and pathology assessment. Without mammogram identification, a biopsy would never be done. With regards to slow growing solid cancers, it’s not uncommon that a tumor stays the same size for many years but gets “turned on” and grows very rapidly within a short space of time. By the time it’s rapidly growing, it may often be too late – having metastasized to other parts of the body. Why take that chance?6 It is also very important to remember that cancers are not all treated the same. Low grade(slow growing) cancers are treated much less aggressively that high grade(fast growing) cancers. As part of the pathology investigation of samples from a biopsy, they determine the molecular subtype, hormone receptor status, grade, growth rate and even genetic attributes. This allows very specific precise treatment suitable to each cancer. If a person is diagnosed with a DCIS, they won’t be exposed to unnecessary radical surgery and huge doses of toxic chemotherapy! Neither will an 85 year old with a slow growing cancer. Often, an anti-hormone medication alone is sufficient. So the fear of being over-treated is unfounded.What about excessive biopsies? A biopsy should only ever be done if an experienced breast radiologist thinks that there is a chance of malignancy based on the mammogram or ultrasound picture. A biopsy in experienced hands is a minor, painless procedure that leaves a small bruise and tiny wound, both of will heal rapidly. It’s a relatively non invasive way to definitively identify or rule out cancer. The bottom line when it comes to getting accurate diagnosis and not be subjected to inappropriate investigations, or false negative results(normal result when there actually is a cancer) is that you the patient must choose a reputable, experienced mammography centre!
  3. Ultrasounds are as good as mammograms for screening for breast cancer. There are very few studies into breast ultrasound as a screening tool in breast cancer detection. So far, none of them have shown an equivalent reduction in mortality as those for mammography. There are some clear disadvantages of breast ultrasound. First and foremost is the inability of ultrasound to identify microcalcifications (too small). As explained above, DCIS can represent an early but potentially dangerous cancer. It is one of the commonest types of breast cancer identified and only mammograms can show it. Secondly, when using an ultrasound, the “window” through which the radiologist views the breast, is the thin edge of the probe, usually only 5cm in length. That’s why the radiologist has to move it back and forth over the whole breast. It’s kind of like examining a field with a magnifying glass – great to show detail of the area you’re looking at, but means you have to move it in small increments over the whole area. You only see a small bit at a time. That makes it easy to miss small things as you move back and forth. The mammogram on the other hand shows a panorama of the entire breast, in two orientations and now 3D. In that way, the radiologist can evaluate the whole breast in seconds without missing any areas. This is why mammograms are considered “screening” tests and ultrasounds are actually better at focused assessment of particular areas. Lastly, mammogram pictures of a patient’s breasts show a pattern of breast tissue that should remain stable year after year. The radiologist will place your old and new mammograms next to each other and scrutinize them for the slightest change (a game of spot the difference). This is a super sensitive method of finding very early cancer changes. You cannot do that with ultrasound. Please also note that you cannot do an ultrasound in order to determine whether a mammogram is needed. If you cannot see microcalcifications on ultrasound, how would you know that you need a mammogram!? It would be reasonable to do a mammogram and then decide if you also need an ultrasound eg if there is dense breast tissue or abnormalities needing further evaluation.
  4. South African Doctors only recommend annual mammograms because they are greedy and want to make money. There are several problems with this argument. Firstly, no one denies that a private practice in South Africa is a for-profit business. 99% of doctors work to make a profit. The question is whether they are doing so unethically. Radiologists are one of the very few medical specialists who charge strictly medical aid rates. The tariff for a mammogram in SA includes a free ultrasound. In addition, we do not charge extra for doing a 3D mammogram(tomosynthesis) and using computer aided detection(CAD) software. In any other country, a private mammogram means a mammogram only (charged at whatever rate they decide). An additional ultrasound, tomosynthesis(3D) and CAD with double the price. We charge one fee, all included and covered by your medical aid, even hospital plans. To put it further in perspective, the medical aid tariff paid for a mammogram has increased by about 6% per year. By comparison, the cost of super high end mammography and ultrasound machines has increased by 50 – 60% on account of the currency deterioration. Regardless of the financial pressure this places on SA radiology departments, and the inability to recoup the costs by increasing tariffs, most departments in SA strive to keep up with the latest technology worldwide. The drive behind that is to have the very best equipment that allows us to better find cancers. There is no increased financial benefit in having cutting edge equipment – the fee is identical whether you have a 1985 analog mammogram machine, or a 2015 Tomosynthesis(3D) Full Field Digital machine. It is also noteworthy that private radiologists follow the same guidelines as departments in public hospitals where you can get a mammogram for free7.
  5. Switzerland has abolished mammograms. Sweden only does breast ultrasounds. It is true that in 2014, Switzerland changed the screening program. They decided to do away with mammogram guidelines in favour of informed decision making by patients ie that it is up to patients whether they do or don’t want mammograms. This was decided by an independent panel of “experts” which included a clinical pharmacologist, nurse scientist, lawyer, and health economist. In other words, no real experts in breast cancer diagnosis. Their recommendations have been slammed by cancer experts in and out of Switzerland8. Just about every other country on earth has a breast cancer screening program involving mammography. With regards to Sweden, the screening guidelines are mammograms every year from age 408.
  6. Mammograms burst cysts. The pressure created by a mammogram is simply not sufficient to burst cysts. At our practice, we do over 5000 mammograms a year. 30 - 40% of patients have cysts. We have never ever seen a patient with a burst cyst caused by mammogram compression. A literature search also shows no proven cases of cyst rupture due to mammogram. It is also important to know that the new 3D mammogram machines apply considerably less compression than the old machines.

 

The bottom line.

Yes, there are doctors and even national health services advocating against mammograms. Searching the internet, you will find many articles and even scientific journals skeptical of the benefits of annual mammography. However, there are many more, based on decades of reputable scientific study, that prove the benefits outweigh the risks / harm.

Recently, there has been more emphasis on patients having the right to choose for themselves whether to have these tests, and I fully agree with that. Noone must be forced to have a test. We live in a free country and the decision is yours. In the old days, we used to see horrific cancers of the breast on a regular basis – huge ulcerating cancers that had taken over the whole breast and obviously metastasized to the bone, lungs, liver and brain. We simply don’t see those anymore. The average diagnosed cancer these days is 1 – 2cm in size and hasn’t spread. That’s a tribute to screening and early detection. Mammograms save lives. You choose.

 

 

References:

  1. Freedman DA1Petitti DBRobins JM. On the efficacy of screening for breast cancer. Int J Epidemiol. 2004 Feb;33(1):43-55.
  2. G van Schoor1, S M Moss2, J D M Otten1, R Donders1, E Paap1, G J den Heeten3, R Holland3, M J M Broeders1,3and A L M Verbeek1,3Increasingly strong reduction in breast cancer mortality due to screeningBritish Journal of Cancer (2011) 104, 910–914.
  3. Olsen, Anne Helene, Njor Sisse H., Vejborg Ilse, Schwartz Walter, Dalgaard Peter, Jensen Maj-Britt, Tange Ulla Brix, Blichert-Toft Mogens, Rank Fritz, Mouridsen Henning, and Lynge Elsebeth. "Breast Cancer Mortality In Copenhagen After Introduction Of Mammography Screening: Cohort Study." BMJ: British Medical Journal 330.7485 (2005): 220-22. Web.
  4. Moss, Sue M et al. Effect of mammographic screening from age 40 years on breast cancer mortality in the UK Age trial at 17 years' follow-up: a randomised controlled trial. The Lancet Oncology , Volume 16 , Issue 9 , 1123 - 1132Swedish Organised Service Screening Evaluation Group. Reduction in breast cancer mortality from the organised service screening with mammography: 2. Validation with alternative analytic methods. Cancer Epidemiol Biomarkers Prev. 2006 Jan;15(1):52-6.
  5. http://www.forbes.com/sites/elaineschattner/2015/07/09/why-women-shouldnt-cower-to-concern-about-breast-cancer-overdiagnosis-by-mammography-jama-news/2/#63f4b8229cb5
  6. http://rssa.co.za/downloads/cat_view/9-news-and-press-releases?start=10
  7. http://www.medscape.com/viewarticle/823781   (Switzerland)
  8. http://www.swedish.org/services/womens-health/our-services/mammography/screening-guideline