August - December 2007 Issue
Clearing Up Confusion About Breast Cancer Screening
Lisa K. Miller, MDMedical College of Wisconsin Diagnostic Radiologist
Co-director of Breast Imaging
A study published in the June 15, 2007, issue of Cancer, the American Cancer Society’s (ACS) journal, shows that mammography screening rates declined by 4 percent between 2000 and 2005. Dr. Lisa Miller discusses possible reasons for the decline and the importance of breast cancer screening. Dr. Miller also explains the different types of breast imaging studies — mammography, breast ultrasound and breast magnetic resonance imaging (MRI).
Q. What did the ACS study show, and what factors are responsible for the decline in breast cancer screening nationally? The ACS study showed that the number of women age 40 and over who reported having a mammogram within the last two years dropped from 70 percent in 2000 to 66 percent in 2005. The drop in mammography screening was most pronounced for women older than age 50, with the sharpest drop reported for women ages 50 to 64 and women in higher socioeconomic groups, both of which had previously shown much higher screening rates. Although the decline in screening rates is small, the direction is a cause for concern.
There are several possible causes for the drop:
- Fewer healthcare facilities are offering mammograms for different reasons including high malpractice risk and modest reimbursement
- More women may be missing routine health care due to inadequate health insurance or other access problems
- Some women may be indifferent about having a mammogram
The timing of this trend coincides with a drop in the reported levels of new breast cancer diagnoses. And the declining breast cancer diagnoses may be related to the declining mammography rates. A continued decline in mammography may result in increased breast cancer deaths.
Q. Is screening for breast cancer still important?Absolutely. Regular screening mammography is one of health care’s most effective tools. The widespread use of mammograms since the 1980s for screening women over age 40 in the United States is viewed as the main reason behind the reduction in deaths due to breast cancer.
Q. What is the gold standard for breast cancer screening?The initial imaging exam to detect breast cancer is a mammogram. This will suffice for most women. However, if findings on a mammogram or a patient’s physical findings or symptoms warrant further investigation, then additional imaging, including ultrasound and MRI, may be indicated.
Q. Is MRI a better option than mammography?Magnetic resonance imaging (MRI) is a supplemental tool for mammography — not a replacement for it. MRI is not currently recommended as a screening exam for women at average risk of developing breast cancer. New guidelines issued by the ACS recommend MRI screening in addition to yearly mammograms for high-risk women who meet one of the following conditions:
- They have a BRCA1 or BRCA2 mutation (an estimated 5 percent to 10 percent of all breast cancers are inherited and are associated with two genes: BReast CAncer gene 1 [BRCA1] and BReast CAncer gene 2 [BRCA2]).
- They have a first degree relative (parent, sibling or child) with a BRCA1 or BRCA2 mutation
- Their lifetime risk of breast cancer has been scored at 20 percent to 25 percent or greater, based on one of several accepted risk assessment tools that look at family history and other factors
- They had radiation to the chest between the ages of 10 and 30
- They have Li-Fraumeni, Cowden or Bannayan-Riley-Ruvalcaba syndromes or an affected first degree relative
Q. Why is it important to know who is reading your screening results, and does this make a difference in your quality of care?One important factor that influences the accuracy of mammography is the experience of the radiologist who interprets the mammogram. Radiologists who read a large number of mammograms each year are generally better able to interpret them than those who read relatively few. Accuracy rates are significantly better when radiologists read at least 2,500 mammograms a year. Women can gain some extra assurance that their mammogram is read accurately by seeking out facilities that conduct a high volume of mammography.
Q. Who reads screening mammograms at Froedtert & the Medical College of Wisconsin?Four experienced, board-certified radiologists at Froedtert & the Medical College of Wisconsin read the mammograms as well as breast ultrasounds and breast MRIs. Interventional breast biopsy procedures, including ultrasound-guided and stereotactic (X-ray-guided) needle biopsies, are also done here. We anticipate performing MRI-guided breast biopsies in the near future.
Source: Every Day
Date: Aug - Dec 2007 Issue