The large study reviewed here found that in women with an abnormal BRCA1 gene, annual screening using BOTH a mammogram and a breast MRI (magnetic resonance imaging) was better at diagnosing breast cancer earlier than annual screening with only one of these tests. Women with an abnormal BRCA1 gene have up to an 85% risk of developing breast cancer over their lifetimes.
The women in this study who had both tests every year were found to live about 1.5 years longer than women who had only one test per year. This survival difference is most likely because the women who had both screening tests were diagnosed with breast cancer at an earlier stage, when it's most treatable. The breast cancers diagnosed using both screening tests were smaller (about 1.1 centimeters) than cancers diagnosed using only 1 test (about 1.3 to 1.9 centimeters).
Mammograms and MRI create images of the breast in different ways. Each test can be better at finding different forms and stages of breast cancer. Using both tests can make it more likely to find breast cancer sooner. This study adds to evidence that suggests MRI alone may be better than mammogram alone for routine screening using only one test. Still, MRI cost and availability make routine screening with MRI impractical for women with average breast cancer risk. Annual mammograms are a good and effective screening method for most women older than 40.
One side effect of using both screening tests each year is more breast cancer "false alarms" -- a strong suspicion of breast cancer when there is no breast cancer. When there's a strong suspicion of breast cancer, doctors usually recommend a breast biopsy. One out of every 3 women in this study had a breast biopsy done when there was no breast cancer. In addition to the discomfort, inconvenience, and expense of extra procedures such as a biopsy, women who have false alarms are understandably anxious and fearful until they get the results back saying they don't have cancer. For women at very high risk for breast cancer, the benefits of aggressive screening (annual mammogram AND MRI) may outweigh the inconvenience of any false alarms. For women who have average breast cancer risk, an annual mammogram with no MRI usually makes the most sense.
If you have an abnormal breast cancer gene or are at high risk for breast cancer because of your personal or family medical history, talk to your doctor about a screening plan that is best for you. This might include getting both mammograms and breast MRIs each year, as well as more frequent screening. You also might want to talk to your doctor about all your options (diet, lifestyle, and exercise choices as well as medical and surgical choices) for keeping your breast cancer risk as low as it can be.
NEW YORK (Reuters Health) - Among women with BRCA1 gene mutations, which are known to increase the risk of breast cancer, annual screening with both mammography and MRI is associated with better survival when compared with screening with either method alone, new research indicates. The trade-offs, however, are a high rate of false-positive results, which lead to unnecessary biopsies.
The findings were based on data from 22 studies that included 8,139 women who carried the BRCA1 gene. In addition, the researchers developed a prediction model based on data from the Surveillance Epidemiology and End Results (SEER) Program (1975-1980) and the Breast Cancer Surveillance Consortium.
The results indicated that annual combined screening with mammography plus MRI increased the average life expectancy by 1.38 years compared with follow-up only without screening tests (clinical surveillance). The false-positive rate was 84.0 percent.
"For women who carry BRCA1 gene mutations, adding annual MRI to annual mammography has a clear benefit in terms of projected life expectancy and breast cancer mortality reduction," lead author Dr. Janie M. Lee told Reuters Health. "Whether the trade-offs related to MRI screening are acceptable to women at increased risk of developing breast cancer is still being investigated."
In the general population, the lifetime risk of breast cancer for women is 13 percent. In BRCA1 mutation carriers, by contrast, this risk can be as high as 80 percent. Strategies to reduce this high risk have included preventative mastectomy, removal of the ovaries (to lower levels of estrogen which can encourage breast cancer growth), preventive chemotherapy, and more frequent office visits, according to the report in the journal Radiology.
Younger women, especially those of childbearing age, are often reluctant to undergo preventative mastectomy, the investigators point out. Preventative chemotherapy might be a suitable choice, but unfortunately no studies to date have shown it to reduce breast cancer mortality. That leaves increased surveillance.
According to the report, mammography is not nearly as sensitive at detecting breast cancers in BRCA1 mutation carriers as it is in the general population. Previous research has shown that MRI can achieve higher sensitivity than mammography, but whether this translates into reduced breast cancer mortality is unclear.
Due to the long length of follow-up and the large number of patients required, the authors note that it is unlikely that any trial will ever investigate whether MRI screening can reduce breast cancer mortality. This prompted Lee, from Massachusetts General Hospital in Boston, and colleagues to conduct the current decision analysis.
The average life expectancy was 71.15 years, the report indicates, and with clinical surveillance alone, the average diameter of breast cancers at diagnosis was 2.6 centimeters. Using annual screening with mammography, MRI, or both, the average tumor diameter at diagnosis fell to 1.9, 1.3, and 1.1 centimeters, respectively.
Compared with clinical surveillance, all three imaging-based screening strategies increased life expectancy and reduced mortality from breast cancer. Again, the most pronounced benefit was with mammography plus MRI.
In addition to the high false-positive rate seen with mammography plus MRI screening, nearly one in three women underwent one or more biopsies for what turned out to be benign disease. The false-positive rates and negative biopsy results with the other screening strategies were also increased, but not as high as that seen with the combined approach.
More research is required to find the optimal sequence and frequency for screening tests for breast cancer, and to "minimize the potentially negative effects on women's health-related quality of life when screening with increased intensity is pursued," Lee noted.
She added that her team is "currently working to extend our model of breast cancer natural history and screening in BRCA1 gene mutation carriers to women who carry BRCA2 mutations, and women whose lifetime risk of breast cancer exceeds 20 percent -- these women are defined by the American Cancer Society as being at 'high-risk' of developing breast cancer."
SOURCE: Radiology, March 2008.
Breastcancer.org 7 East Lancaster Avenue, 3rd Floor Ardmore, PA 19003
Learn more about our commitment to your privacy
© 2009 Breastcancer.org - All rights reserved.
Breastcancer.org is a non-profit organization dedicated to providing information and community to those touched by this disease. Learn more about our commitment to providing complete, accurate, and private breast cancer information.
