Women who've been diagnosed with breast cancer are at risk for the cancer coming back (recurrence) and also have a higher-than-average risk of being diagnosed with a new, second breast cancer. So regular breast cancer screening is very important for women with a personal history of breast cancer.
A study found that annual screening mammograms were less effective (less sensitive) at finding breast cancer in women with a personal history compared to women never diagnosed with breast cancer.
The researchers reviewed the screening mammogram readings of two groups of women:
- 58,870 mammograms in 19,078 women with a history of early-stage breast cancer
- 58,870 mammograms in 55,315 women never diagnosed with breast cancer
To compare the effectiveness of the mammograms, the researchers "matched" women who weren't diagnosed to women who were. This means that the women's ages, breast density, mammogram facility, and mammogram timing were similar.
Breast density is the amount of fatty tissue compared to the amount of non-fatty tissue in the breast. A denser breast has more non-fatty tissue in it than a less-dense breast. Mammograms are less effective at finding cancer in dense breasts.
Matching the women helps make sure that any differences in the screening mammograms' ability to detect breast cancer are linked to breast cancer history and not other differences (breast density, mammogram facility) that could affect how well a mammogram detects cancer.
The researchers looked at the medical histories of all of the women each year after each screening mammogram. Not surprisingly, women with a personal history of breast cancer were much more likely to be diagnosed with breast cancer -- a recurrence or a new, second breast cancer -- compared to women who had never been diagnosed.
Within 1 year after screening:
- 655 breast cancers were diagnosed in women with a personal history of breast cancer
- 342 breast cancers were diagnosed in women without a personal history of breast cancer
Most of the breast cancers were diagnosed at an early stage.
Screening mammograms found 76.5% of breast cancers diagnosed in the women WITHOUT a personal history of breast cancer compared to 65.4% of breast cancers diagnosed in the women WITH a personal history of breast cancer.
Screening mammograms were least effective in finding breast cancer in women with a personal history of breast cancer and one or more of the following characteristics:
- younger than 50
- dense breasts
- received chemotherapy to treat the first breast cancer
Although not common, some of the women were diagnosed with breast cancer after a negative screening mammogram (called an interval diagnosis). This could happen because a woman felt a breast lump or developed a symptom that led to a cancer diagnosis. This study found that interval diagnoses were 2.5 times more likely in women with a personal history of breast cancer compared to women without a personal history.
Based on the results, the researchers said that regular screening mammograms should still be an important part of screening in women with a personal history of breast cancer. Still, the results suggest that women with a personal history of breast cancer may need other screening tests -- such as breast MRI or breast ultrasound -- in addition to screening mammograms.
Other research has shown that breast MRI in the screening plan of some high-risk women, including women with a personal history of breast cancer, may make sense. Some experts think that screening with 3-D mammograms also may be especially useful for women with a personal history of breast cancer. The FDA has approved a three-dimensional mammogram system for screening.
If you've been diagnosed with breast cancer you and your doctor should develop a screening plan tailored to your unique situation. If the plan includes only regular mammograms, you may want to talk to your doctor about the results of this study and ask if breast MRI or ultrasound in addition to mammograms might make sense for you.
You can learn more about mammograms and other ways to screen for breast cancer in the Breastcancer.org Screening and Testing section.