We’ve just made it through another pink obsessed breast cancer awareness month. As usual, the predominant message has been one of early detection rather than prevention. It’s the same message every year: “Find breast cancer early early and you can beat it.”
Finding it early means taking part in mammographic screening programs. In New Zealand, they’re recommended from the age of 45 to 69 (it varies from country to country).
One of the most staunch advocates of mammographic screening has always been the American Cancer Society. In an unprecedented about-turn, the ACS has recently said the benefits of early detection through screening programs of cancers, especially of the breast and prostate, have been significantly overstated.
The well respected Nordic Cochrane Centre in Denmark has raised questions about the benefits of mammograpy (especially for women under 50 and over 70) for several years. Their studies suggest that:
1. For every 2000 women (aged 50-69) having regular screening over a 10 year period, one woman will have her life prolonged. Ten healthy women who would not have been diagnosed if it were not for screening will be diagnosed as breast cancer patients and treated unnecessarily.
2. The “10 healthy women” described, are women with an extremely common pre-cancerous breast lesion called Ductal Carcinoma In Situ (DCIS). This condition often sits quietly in the breasts for decades without becoming life threatening breast cancer. Sometimes it spontaneously disappears, and often it’s something a woman dies with rather than of. Unfortunately we don’t yet have the ability to differentiate between this more common form of DCIS and the minority of cases which will go on to become invasive. Hence, all DCIS detected through screening programs is (often unnecessarily) aggressively treated.
In July this year the British Medical Journal (BMJ) published another study that attempted to determine how much of this type of “overdiagnosis” (detection of cancers that will not cause death or symptoms) was occurring with screening. Their answer? A shocking one in three breast cancer diagnoses fell into this category. These are “cancers” which would never have progressed and would never have been life threatening.
Also, in the BMJ Professor of Medicine Gilbert Welch considered the pros and cons of a typical 50-year-old woman considering having the recommended annual screening. He found that for such a woman:
1. One in 1000 women annually screened for 10 years would avoid dying from breast cancer.
2. Between two and 10 women will be over-diagnosed and endure unnecessary treatment which may include mastectomy, radiotherapy or chemotherapy.
3. Ten to 15 women will be told they have breast cancer earlier than they would have otherwise been told, but it will not effect their prognosis.
4. Between 100 and 500 women will have a “false alarm” (being told they have cancer when they don’t), and will undergo mental anguish and a biopsy.
In America alone, 40,000 women die of breast cancer each year despite mammographic screening. New Zealand women add another 650 deaths to the global tally each year. Many of these deaths are the result of aggressive, fast growing cancers, often in younger women. Younger women have dense breast tissue making mammographic screening much less reliable.
Instead of pouring more and more money and resources into mammographic screening programs with extremely dubious value for many women, perhaps there is a better use of our money? What if some of the billions of dollars poured into screening programs was instead devoted to research into prevention?
For example, despite vast amounts of empirical evidence, very little money or attention is given to researching the connection between environmental pollution and breast and prostate cancer. There is much significant evidence that our toxic world, filled with hormonally disruptive synthetic chemicals is a significant driver for the ever increasing epidemic of breast cancer.
Here’s a novel thought: Instead of finding it early, we prevent it in the first place?
