Why Mammograms?

A post by BreastScreen popped up in my Facebook feed today. For those from overseas, this Australian government initiative provides free mammograms to women, with a focus on those between 50 and 74 years of age.

The age restrictions aren’t arbitrary. They are based on evidence that this is the window where a mammogram is most likely to detect cancer. All Australian women within this group are offered a free test every two years.

Women between 40 and 50 are advised to talk to their doctor about whether or not a mammogram is advisable. They can attend BreastScreen for a free test if there’s a reason to do so, such as a family history of breast cancer, or a medical history that leads a doctor to conclude that a patient is at higher risk. This history might not be related to previous cancer or benign tumours. It could be that someone has ‘lifestyle factors’ like smoking, obesity or excessive alcohol consumption that put them at higher risk.

Mammograms are not routinely offered to women under 40 because the test is likely to be less effective. Breast density declines with age and it can be difficult to detect cancer using a mammogram in younger women. For women 75 and over, routine testing is no longer considered necessary. Generally, if you’re going to get breast cancer you will have developed it before this age. That’s not to say that women in this age bracket shouldn’t continue to practice self-examination and to request a test via their doctor if they suspect anything is wrong. It’s just that the incidence of cancer in this age group doesn’t justify the cost, inconvenience and small risk associated with testing.

Yes. Small risk.

It’s not uncommon to see any post about mammograms followed by at least a few comments recommending against them. The arguments usually state that the radiation is toxic and that testing may actually cause cancer. There are also concerns about ‘false positives’ which result in women receiving unnecessary and potentially life-threatening treatment, ‘false negatives’ where a woman with cancer is told she doesn’t have it, and a reliance upon research that is cited as evidence that free mammograms have no benefit. Here’s a typical article:

Why you shouldn’t have mammograms

This is another example of a very complex issue being dumbed down in pursuit of internet popularity. The truth is a lot more subtle. There’s the usual difficulty with any piece of research related to breast cancer; we’ve seen huge changes in treatment and technology in the last two decades. We now have lower radiation used in diagnostic equipment, better treatment following diagnosis and ongoing research that will continue to impact upon detection and treatment.

One of the greatest discoveries since the introduction of free mammograms and the subsequent analysis of data was that some early cancers seem to heal themselves. This is why the early detection of DCIS (ductal carcinoma in situ) may have previously resulted in treating a condition that would have gone away all on its own. But here’s the catch. Not ALL DCIS goes away on its own! If you were previously diagnosed and treated for DCIS then it could be that any treatment you had was entirely unnecessary. It could also be that this early treatment saved your life and your breast.

Research is now focused on figuring out which types of DCIS are likely to resolve all on their own. It’s hoped that in the future, doctors will be able to determine which cases need treatment and which should be given a bit more time to see if they resolve on their own. In the mean time, I would still be recommending screening on the basis that I’m not prepared to accept a dice roll when it comes to cancer.

Of course I need to declare a bias. BreastScreen detected four tumours in my left breast the very first time I had a free mammogram. This was not DCIS. This was full blown triple negative breast cancer. My tumours were doubling every three weeks and I was fortunate enough to have received my BreastScreen invitation at a Goldilocks moment; my tumours were just large enough to be detected but had not yet metastasised.

You should know that at the time, I was, to all outward appearances, physically fit. I was probably about 15 kilos over my ideal weight, but hardly obese. I was a non-smoker who enjoyed sharing a bottle of wine with my husband over dinner (before I discovered it was a category one carcinogen, just like cigarettes) and I regularly practiced self-examination after every menstrual cycle. I had no palpable lumps in my breasts but the mammogram found four tumours.

To say that this test saved my life is not an exaggeration. Without it, I would have had no indication that anything was wrong until the impact of the cancer spreading throughout my body became apparent. Triple negative is rarer and more aggressive than other types of breast cancer, with a lower survival rate.

You see this is my bottom line about research and data. None of it counts for anything much if yours is the life that’s saved. Here’s a link to one of the pieces of research that’s often cited when demonising breast screening:

Possible net harms of breast cancer screening

It’s always useful to go to the source when the internet scares you. The most significant thing about this research in my opinion is that they do not dispute the fact that mammograms save lives. Their argument is that screening also results in a reduction of quality of life in those women incorrectly diagnosed and treated because of the ‘months of psychological distress’ they experience. They also argue a reduction in quality of life for those whose cancer goes undetected.

I’ll deal with the last group first. If a mammogram did not detect your cancer then it is usually the case that you had no other evidence of cancer. Lumps, swelling, pain or any other abnormality of the breast would warrant further testing, including ultrasound and biopsy. The fact that screening does not have a 100% detection rate needs to be balanced agains the fact that mammograms save lives.

The over treatment of some women is a serious issue and there can be no doubt that waiting several weeks (rarely months) while you worry about a suspicious lump is definitely distressing. There can be no question that the research into reducing this type of event will greatly improve this situation. In the mean time I’d like you to consider things from a personal perspective. These are the possible outcomes from your routine mammogram:

  1. It detects a cancer that you didn’t know you had and this detection saves your life.
  2. It detects a cancer that you didn’t know you had and that cancer ultimately kills you. Treatment may or may not give you a few more precious months or years with those you love. Certainly early detection will improve your chances.
  3. It detects a cancer that you didn’t know you had and you die as a consequence of your treatment (neutropenia, staph infection, heart failure during surgery etc) but left untreated the cancer was killing you in any case.
  4. It detects a cancer or a pre-cancerous condition that you didn’t know you had that would have resolved itself without medical intervention and this results in you being anxious. It may also result in you having a lumpectomy that reveals a benign lump. This will be frightening but will ultimately reassure you that you don’t have cancer (and probably also inspires you to reassess your life and the choices you make).
  5. No cancer is detected, even though you have cancer. In time your cancer will either resolve itself or become apparent. If you have any symptoms you should request other forms of testing and not rely upon a negative mammogram.
  6. No cancer is detected because you do not have cancer.

Here’s the thing. There is absolutely no way of knowing which of these categories you fall into without actually having the mammogram. Take a good look at point number one again and ask yourself, “Am I prepared to take that risk?”

Before you roll that particular dice it would be a good idea to know your odds. I mean, if the risk of getting breast cancer was one in a million you’d be justified in wondering if the discomfort and low radiation dose associated with a mammogram was worth it. But if you’re an Australian woman your odds of developing breast cancer are one in eight.

One in eight.

The risk is similar throughout the developed world. Here’s a link with the current statistics:

Breast cancer statistics

Add to that the clear evidence that early detection improves survival, and helps to minimise the risks and side effects associated with treatment.

Thanks to early detection I had no spread of cancer to my lymph nodes. Once triple negative escapes to the lymphatic system it spreads, typically to bone, lungs or brain. Give me early detection.

Early detection might also mean that you can have a lump excised and keep your breast, rather than having the breast removed. It could mean that you avoid the risks, discomfort and possible side effects of chemotherapy or radiation. It could mean faster and fuller recovery from cancer.

So the next time someone tries to tell you that a mammogram will kill you, you might like to respond with this:

How do you know that?

It’s my favourite question for people quoting an internet article. In fact the research clearly shows that mammograms save lives. You might also like to send them this excellent article about the mammogram controversy:

Mammograms save lives

I know. It would be easier to just smile and nod and walk away, but these people are dangerous. I have met women that refuse to have free testing because of the scare campaigns. I just hope they aren’t one of the one in eight that will develop breast cancer, because, by the time they do it might be too late to save them.

Advertisements