Are there any potential risks to having a screening mammogram? (Part 1)

Yes, you should know about some possible problems with having routine mammograms.

1. Mammograms do not always find breast cancer.

Mammograms can find most invasive breast cancer, but they miss some. If 100 women under age 50 with invasive breast cancer have a mammogram for the first time, the cancer will show up on the mammogram in about 70 of these women. The other 30 women with breast cancer will have normal mammograms. Thus, mammograms can miss cancer, and having a normal mammogram does not rule out the possibility of having breast cancer.

Mammograms find a higher percentage of breast cancers in women over age 50. If 100 women over age 50 with invasive breast cancer have a mammogram for the first time, the cancer will show up on the mammogram in about 85 of these women. The other 15 women with breast cancer will have normal mammograms.

References:
Kerlikowske KM, Grady DG, Barclay J, Sickles EA, Ernster V. Effect of age, breast density, and family history on the sensitivity of first screening mammography? JAMA 1996;276:33-38.
Kerlikowske K, Barclay J. Outcomes of modern screening mammography. Mongraph Natl Cancer Inst 1997;22:105-111.
Kerlikowske K, Carney P, Geller B, Mandelson MT, Taplin S, Malvin K, Ernster V, Urban N, Cutter G, Rosenberg R, Ballard-Barbash R. Performance of screening mammography among women with and without a first-degree relative with breast cancer. Ann Intern Med 2000;133:855-863.