Effect of observing change from comparison mammograms on performance of screening mammography in a large community-based population.
OBJECTIVE
To evaluate the effect of comparison mammograms on accuracy, sensitivity, specificity, positive predictive value (PPV(1)), and cancer detection rate (CDR) of screening mammography to determine the role played by identification of change on comparison mammograms.


METHODS
This HIPAA-compliant and institutional review board-approved prospective study was performed with waiver of patient informed consent. A total of 1,157,980 screening mammograms obtained between 1994 and 2008 in 435,183 women aged at least 40 years were included. Radiologists recorded presence of comparison mammograms and change, if seen. Women were followed for 1 year to monitor cancer occurrence. Performance measurements were calculated for screening with comparison mammograms versus screening without comparison mammograms and for screening with comparison mammograms that showed a change versus screening with comparison mammograms that did not show a change while controlling for age, breast density, and data clustering.


RESULTS
Comparison mammograms were available in 93% of examinations. For screening with comparison mammograms versus screening without comparison mammograms, CDR per 1000 women was 3.7 versus 7.1; recall rate, 6.9% versus 14.9%; sensitivity, 78.9% versus 87.4%; specificity, 93.5% versus 85.7%; and PPV(1), 5.4% versus 4.8%. For screening with comparison mammograms that showed a change versus screening with comparison mammograms that did not show a change, CDR per 1000 women was 25.4 versus 0.8; recall rate, 41.4% versus 2.0%; sensitivity, 96.6% versus 43.5%; specificity, 60.4% versus 98.1%; and PPV(1), 6.0% versus 3.9%. Detected cancers with change were 21.1% ductal carcinoma in situ and 78.9% invasive carcinoma. Detected cancers with no change were 19.3% ductal carcinoma in situ and 80.7% invasive carcinoma.


CONCLUSIONS
Performance is affected when change from comparison mammograms is noted. Without change, sensitivity is low and specificity is high. With change, sensitivity is high, with a high false-positive rate (low specificity). Further work is needed to appreciate changes that might indicate cancer and to identify changes that are likely not indicative of cancer.
Carolina Mammography Registry, Department of Radiology, University of North Carolina School of Medicine, Mason Farm Rd, CB 7515, Chapel Hill, NC 27599-7515, USA. bcy@med.unc.edu
Bonnie C
BC
Yankaskas
Ryan C
RC
May
Jeanine
J
Matuszewski
J Michael
JM
Bowling
Molly P
MP
Jarman
Bruce F
BF
Schroeder
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016015:Logistic Models; D008327:Mammography; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012042:Registries; D012680:Sensitivity and Specificity; D013997:Time Factors