Evaluating the correlation between film mammography and MRI for screening women with increased breast cancer risk.
OBJECTIVE
Breast magnetic resonance imaging (MRI) is increasingly being added to mammography for screening asymptomatic women at increased risk of breast cancer. Because the direction and extent of correlation between mammography and MRI could potentially result in over- or underestimation of the diagnostic gain related to using MRI as an adjunct to mammographic screening, we performed an analysis to evaluate the extent of correlation between mammography and MRI.


METHODS
We reviewed the published literature to identify multimodality breast cancer screening studies reporting the sensitivity of mammography and MRI, alone and in combination, for breast cancer diagnosis. After calculating the expected sensitivity of combined mammography and MRI under conditions of test independence (no correlation), we compared the calculated and observed sensitivities for combined mammography and MRI. We then calculated correlation coefficients for mammography and MRI.


RESULTS
Seven studies of multimodality screening in women at increased risk of developing breast cancer were included for analysis. Of these studies, the correlation between film mammography and MRI was positive in three studies, negative in two studies, and not identified in two studies. The calculated correlation coefficients ranged from -0.38 to 0.18. In six of seven studies, the 95% confidence interval for the correlation coefficient included 0.0, indicating no significant correlation.


CONCLUSIONS
Evidence from published trials of multimodality breast cancer screening identified no statistically significant correlation between film mammography and MRI. Using both tests for breast cancer screening is likely to improve the early detection of breast cancer in women at increased risk.
Lee
Janie M
JM
Department of Radiology, Massachusetts General Hospital, Institute for Technology Assessment, 101 Merrimac Street, 10(th) Floor, Boston, MA 02114, USA. jlee45@partners.org
Halpern
Elkan F
EF
Rafferty
Elizabeth A
EA
Gazelle
G Scott
GS
D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008327:Mammography / Q000706:statistics & numerical data*; D008403:Mass Screening / Q000706:statistics & numerical data*; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014962:X-Ray Film / Q000706:statistics & numerical data*