Now let's look at the breast cancer numbers.

Unfortunately, breast cancer is all too common.  Let's review the numbers.  Of all non-skin invasive cancers, 26% are breast cancers.  To personalize the numbers, we can look at the statistics another way.  1 in 8 women will get breast cancer in a lifetime.  That means 12.5% of women will ever be diagnosed with breast cancer.  Again, that is lifetime risk.  To personalize even more, we can look at risk by decade.  The chance of a 50 year old women developing breast cancer in the next ten years is 1 in 40 or a 2.5% risk in her 50's.  The risk increases with age to achieve the lifetime risk quoted so often of 1 in 8.  This data available online www.seer.cancer.gov.

Those risks given above translate into almost 210,000 women newly diagnosed with breast cancer in 2010 in the US.  70% are over 50 years old and 70% have no family history of breast cancer.  The median age at diagnosis is 61 years.  

If we look at the incidence in the last 25 years something interesting is uncovered.  The number of new cases in the US rose to a peak in 1999 and then began to slowly drop until 2006-2007.  Latest data (Cancer Epidemiol Biomarkers Prev published online Feb 28, 2011) show that the decline in incidence rates have leveled off.  The reasons that the breast cancer rates fell for a few years and now are no longer falling are not clear and will be the subject of many other blogs, but you get the idea of the magnitude of the problem.

Fortunately, we have made some advances in early diagnosis and treatment of breast cancer so that the number of women dying from the disease has been slowly and steadily decreasing since the early 1990's.  Treatments are more effective.  Although some think early detection is another key to this decline, we now have the opportunity to reduce the numbers of women who ever get breast cancer.  Exercise is one way to reduce the risk (yesterday's blog and many more to come) and we will see that there are others.  The American Institute of Cancer Research (www.aicr.org) estimates that 75,000 breast cancers a year can be prevented!