Shopping at my local pharmacy last week, I was taken aback by a product on the counter: “Self check breast cream”. In large font was the message “self checking your breasts is important”.
This is a fairly familiar message. But is it true? The evidence is surprisingly complicated.
Breast cancer screening
Breast cancer is a common and important disease. Affecting about one in eight women at some point in their lives, it is the second most common cause of cancer death in Australian women. I’ve seen it profoundly affect many people, including several of my general practice patients. Preventing this would be wonderful. (Watch: How to check your breasts. Post continues after video.)
Cancer screening means looking for cancer in people without symptoms. An established (though still controversial) example is mammography: breast X-rays. Another less established method is breast self-examination.
At first glance, being offered a chance of finding cancer early sounds like a good thing. But it’s more complicated than that. Some screening tests, despite good intentions, fail to help, or even cause harm.
There are various ways screening can mislead us. Screen-detected cancers often show better survival rates than other cancers, but this doesn’t mean the screening is saving lives.
It can instead mean we’re just detecting the cancer earlier without changing its course, or that the screening is picking up some so-called “cancers” that would never have caused symptoms (this is called “overdiagnosis”). (Post continues after gallery.)