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February 26, 2008 NEW YORK (Reuters Health) - Among women with BRCA1 gene mutations, annual screening with both mammography and MRI is associated with better survival than with either screening modality alone, new research indicates. The downside, however, is a high rate of false-positive results and biopsies for benign disease. The findings, reported in Radiology for March, are based on a Markov Monte Carlo decision analysis using data from the Surveillance Epidemiology and End Results database (1975-1980). "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." 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 led Dr. Lee, from Massachusetts General Hospital in Boston, and colleagues to conduct a decision analysis in a model incorporating 500,000 25-year-old women who were asymptomatic BRCA1 mutation carriers. The average life expectancy was 71.15 years, the report indicates, and with clinical surveillance alone, the median diameter of identified breast cancers was 2.6 cm. With annual screening with mammography, MRI, or both, the median diameters fell to 1.9, 1.3, and 1.1 cm, respectively. Compared with clinical surveillance, the corresponding increases in life expectancy with the three imaging-based screening strategies were 0.80, 1.10 and 1.38 years, respectively. False positive rates, however, were 53.8% with mammography, 80.2% with MRI, and 84.0% with both modalities, and corresponding rates of biopsies for benign disease were 11.3%, 26.3% and 30.3%. "Further research is needed to establish the optimal sequence and frequency of MRI and mammographic screening, and to minimize the potentially negative effects on women's health-related quality of life when screening with increased intensity is pursued," Dr. 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%, as these are women defined by the American Cancer Society as being at 'high-risk' of developing breast cancer." Copyright 2008 Reuters. Click for Restrictions.
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