Mammography is Far from Perfect

Breast Cancer is responsible for 40,000 deaths per year in the United States and there will be 178,000 new cases of breast cancer this year. The most important screening tool available for detecting breast cancer is the mammogram, but it is far from perfect. These are sobering statistics. What can you do to make the best of this situation?

According to a study published in the Journal of the National Cancer Institute in December 2007, you need to be aware of several things when it comes to mammograms and breast cancer. This study was led by Diana Miglioretti, PhD, researcher for Group Health Center for Health Studies in Seattle and involved 123 Radiologists reading 36,000 diagnostic mammograms. The study covered 72 facilities where diagnostic mammograms are given in the US from 1996 to 2003. You need a paid subscription to the Journal of the National Cancer Institute to read the actual study, but the news media has reported on it and there are references to those sources at the end of this article.

The study was conducted based on diagnostic mammograms, which are done when a lump or suspicious symptom is already present. This is the next step after a general screening mammogram. By comparison, 5 out of 1000 women having a screening mammogram will have cancer while 44 out of 1000 women having a diagnostic mammogram will have cancer. So the study focused on the more serious and closely read diagnostic mammograms.

It turns out that even the most skilled Radiologists, reading the more serious diagnostic mammograms, missed seeing the cancer in 1 out of 5 women, or 20% of the time. Less skilled Radiologists missed seeing the cancer 30% or more of the time. This is not because the radiologists are careless or untrained - it is because mammograms are very hard to read. Breast lesions look similar whether they are benign or malignant. Two different radiologists reading the same mammogram are likely to disagree.

What the study did conclude, however, is that the best radiologists are those who specialize in breast imaging and those who are affiliated with an academic medical center. These same radiologists tended to have slightly higher false-positive rates, but that seems to be a trade-off for their diligence in diagnosing the presence of breast cancer.

Here are some things for you to consider about breast cancer and mammograms based on the most recent research:

1. Perform regular self examinations of your breasts each month. Pick a date or mark your calendar to remind yourself.

2. Have regular mammograms after age 40. Mammograms may not be perfect, but they are the best method of early cancer detection available.

3. Know the signs of breast cancer and go to the doctor immediately if you notice any of these symptoms: a lump or thickening in the breast that you can feel; a change in size or shape of the mature breast; swelling, redness, warmth, tenderness or scaliness of the breast; a dimple or indentation in the breast tissue or nipple; discharge from the nipple; enlarged lymph node under the arm. Do NOT ignore any of these symptoms.

4. Seek out a radiologist who specializes in breast imaging. Drive farther to go to a teaching hospital or academic facility to have a mammogram - especially a diagnostic mammogram.

5. Don't accept the results of any mammogram as accurate whether they are positive or negative. Trust your instincts and if you think something is wrong, pursue further testing in spite of a positive mammogram. By the same token, pursue a negative result to see if it was a mis-diagnosis.

Mammograms are an imperfect science and an often unwelcome inconvenience. But a mammogram to screen for breast cancer may just save your life.

sources:
Julie Steenhuysen, "Mammogram accuracy varies by radiologist: study", Reuters
Judy Peres, "Detecting breast cancer depends on doctor, study finds", chicagotribune.com
Kyung M. Song, "Even top docs missing signs of cancer on mammogram", The Seattle Times
"Breast Cancer", MayoClinic.com
"Mammography Facts", Planmed.com