Specificity of clinical breast examination in community practice.
BACKGROUND
Millions of women receive clinical breast examination (CBE) each year, as either a breast cancer screening test or a diagnostic test for breast symptoms. While screening CBE had moderately high specificity (approximately 94%) in clinical trials, community clinicians may be comparatively inexperienced and may conduct relatively brief examinations, resulting in even higher specificity but lower sensitivity.


OBJECTIVE
To estimate the specificity of screening and diagnostic CBE in clinical practice and identify patient factors associated with specificity.


METHODS
Retrospective cohort study.


METHODS
Breast-cancer-free female health plan enrollees in 5 states (WA, OR, CA, MA, and MN) who received CBE (N = 1,484).


METHODS
Medical charts were abstracted to ascertain breast cancer risk factors, examination purpose (screening vs diagnostic), and results (true-negative vs false-positive). Women were considered "average-risk" if they had neither a family history of breast cancer nor a prior breast biopsy and "increased-risk" otherwise.


RESULTS
Among average- and increased-risk women, respectively, the specificity (true-negative proportion) of screening CBE was 99.4% [95% confidence interval (CI): 98.8-99.7%] and 97.1% (95% CI: 95.7-98.0%), and the specificity of diagnostic CBE was 68.7% (95% CI: 59.7-76.5%) and 57.1% (95% CI: 51.1-63.0%). The odds of a true-negative screening CBE (specificity) were significantly lower among women at increased risk of breast cancer (adjusted odds ratio 0.21; 95% CI: 0.10-0.46).


CONCLUSIONS
Screening CBE likely has higher specificity among community clinicians compared to examiners in clinical trials of breast cancer screening, even among women at increased breast cancer risk. Highly specific examinations, however, may have relatively low sensitivity for breast cancer. Diagnostic CBE, meanwhile, is relatively nonspecific.
Fenton
Joshua J
JJ
Department of Family and Community Medicine, University of California, Davis, Sacramento, CA 95817, USA. joshua.fenton@ucdmc.ucdavis.edu
Rolnick
Sharon J
SJ
Harris
Emily L
EL
Barton
Mary B
MB
Barlow
William E
WE
Reisch
Lisa M
LM
Herrinton
Lisa J
LJ
Geiger
Ann M
AM
Fletcher
Suzanne W
SW
Elmore
Joann G
JG
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D015331:Cohort Studies; D003153:Community Health Services / Q000379:methods; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods; D010820:Physicians; D012189:Retrospective Studies; D012680:Sensitivity and Specificity