Breast Mammograms May Mean Over - Diagnosis of Breast Cancer

Today breast cancer is the second leading cause of death in women, after lung cancer. As a result, yearly breast mammograms have become common for women over 40, or anyone at high risk of developing this dangerous, disfiguring disease.

Now that programs like this are in place, experts had expected that the number of cases of advanced breast cancer would drop off, but that's not happening.

Instead the incidence of breast cancer seems to have gone up since widespread screening became part of our yearly exams. Why?

Women know that early detection of breast cancer can save lives, but that doesn't make going for that yearly mammogram any less nerve wracking or uncomfortable.

We endure the testing because we've been told we need to find lumps when they're too small to feel or bring symptoms, before they have a chance to grow and cause trouble.

But do all cancers cause problems?

Late last year a large Norwegian study of mammography screening for breast cancer found that some invasive cancers might spontaneously regress over time, leaving no sign that they were ever present in a woman's body.

Makes you wonder, now that we can screen for it, if this type of cancer isn't over diagnosed or over treated.

This latest BMJ report citing an over-diagnosis rate for invasive breast cancer of 35% could truly have you re-thinking that yearly mammogram.

Besides this type of cancer, over-diagnosis has also been mentioned for cancer of the prostate as well as neuroblastoma, melanoma, thyroid cancer and lung cancer.

The latest work on over-diagnosis comes from researchers out of the Nordic Cochrane Centre in Copenhagen.

The team looked at the findings of studies that spanned a 14-year period. 7 years before public mammography screenings were available, and 7 years after government run mammography-screening programs were in place in five different countries (United Kingdom, Canada, New South Wales, Australia, Manitoba, Sweden and areas in Norway)

They found an over-diagnosis rate of 52% for all cancers, 35% for invasive breast cancer.

The data shows a jump in breast cancer incidence just after the screening programs were put in place.

What this work suggests, as did the Norwegian study before it, that perhaps not all cancers need to be treated, some might grow too slowly to affect a patient and others may resolve on their own.

It's important to know that no doctor or current screening technique can tell the difference between a cancer that's dangerous and one that might not be.

In a BMJ editorial that's published along with the research, professor of medicine Dr. H. Gilbert Welch of the Dartmouth Institute for Health Policy and Clinical Research recognizes the problem of over-diagnosis, understanding the trauma and terror a woman endures after being given such news by her doctor.

Surgery and chemotherapy bring their own set of difficulties that are physically demanding and emotionally draining, and a terrible trial for patients and families. Especially those whose cancers might not have needed to be treated at all.

While this latest study is still not an excuse, or recommendation, to put off your yearly mammogram, it does raise some rather nagging questions.

Until we know more, each woman has to decide for herself whether to continue with yearly breast mammograms, but it is clear that screening has let us detect earlier cancers and start treatment earlier.