This is a public service announcement. If you see an e-mail circulating about demanding a thyroid guard for a mammogram, ignore it.
Dr Oz, the TV talk-show doctor, is obviously a smart guy. Depending on how much you believe wikipedia, Dr Oz graduated from Harvard, then went on to obtain a joint MD and MBA in 1986. He specialised as a cardiothoracic surgeon. So the man is talented.
But sometimes even the smartest people make errors. During a show on thyroid cancer, Dr Oz asserted that thyroid cancer was caused in part by the radiation dose received to the thyroid from mammograms, and that all women should ask for thyroid shields (a lead apron for your neck) when having a mammogram.
Misinformation behaves like a viral infection. The mistruth infects the trust of a small group of people, and the idea spreads quickly through their social networks, disrupting and destroying the confidence that had established itself in the community.
Anecdotally, a number of women have presented for their mammogram, asking for their thyroid shield. And when told they’re not routinely used, they have cancelled their mammograms in a huff, complaining that the screening service was obviously deficient.
For Oz, it’s all about a patients rights. “Mammography makes a ton of sense, but you have the right to ask for a thyroid guard,” he said. “This is only going to happen if you make it happen. If you don’t ask those tough questions, there isn’t going to be any change. But if you do ask them, you have the power to make us doctors adjust to you and customize your care.”
That’s great for a TV show sign off, leaving the audience with the warm fuzzy glow of empowerment. But true empowerment isn’t just turning up to a doctor and demanding things Dr Oz or Google said were essential to life, just as good medical care isn’t the doctor smiling at you condescendingly, while giving you a script without any explanation. Empowerment is getting the best information from your doctor and working on a way of tailoring that information to your particular needs.
The converse to the empowerment principle is caustic. Giving the wrong information is disempowering, because every choice stemming from the wrong information is still wrong. While he probably had the best intention, Dr Oz’s mistruth still results in potential harm to thousands of women.
When it comes to mammograms, the radiation dose to the breast is still low by X-ray standards. The scatter that would be absorbed by the thyroid would only be a small fraction of this already low dose. In a follow up show, experts in breast health told Oz that the radiation dose exposure to the thyroid gland after 40 years of annual mammograms would be less than the background radiation received by sitting in a television studio for 60 minutes.
The American College of Radiology and Society of Breast Imaging quantified the effects of this scatter as increasing the thyroid cancer risk by one in 17 million women. According to those statistics, you’d have more chance of winning the lottery.
Even if thyroid cancer was significantly affected by mammography, the overall risk of thyroid cancer is smaller than breast cancer. Thyroid cancer in women has an incidence of 16.3 per 100,000 women. Breast cancer incidence is 124 per 100,000 women, and sadly, 24 per 100,000 women died from breast cancer. So breast cancer is eight times more likely than thyroid cancer. And the number of women dying from breast cancer is higher than the total numbers of thyroid cancers being diagnosed. So having a mammogram is more likely to save your life rather than to end it.
You may agree at this point that the risk is very low. But why not just use the thyroid shield anyway? Even if the risk is microscopic, reducing it further would still of benefit, right? Well, not really, since the breast tissue fans out from the main “mound” of the body of the breast. Some breast tissue extends up to the collar bones and the armpit, and tumours in this peripheral part of the breast tissue would be obscured by wearing a thyroid guard. So its possible to actually increase the risk of harm by wearing a thyroid shield.
For women living in Australia, the current guidelines are that women over 40 can have mammograms every two years, through their state-based breast screening clinic. For Queensland women, this is BreastScreen Queensland. It is also beneficial to have a breast examination done by your GP at regular intervals, and the easiest way to do this is to have a breast check done with your pap smear.
For more information, Queensland Health issued a statement regarding the thyroid scare: http://www.health.qld.gov.au/news/media_releases/qhthryoidcancer0415.pdf
A brochure from the American Thyroid Association discusses thyroid cancer in more detail: http://www.thyroid.org/patients/brochures/ThyroidCancer_brochure.pdf
So, have regular mammograms, don’t ask for a thyroid shield, and if you see the e-mail about Dr Oz, just delete it.