Accuracy of colposcopy in the diagnostic setting compared with the screening setting.
OBJECTIVE
To estimate the accuracy of colposcopy to identify cervical precancer in screening and diagnostic settings.


METHODS
As part of a larger clinical trial to evaluate the diagnostic accuracy of optical spectroscopy, we recruited 1,850 patients into a diagnostic or a screening group depending on their history of abnormal findings on Papanicolaou tests. Colposcopic examinations were performed and biopsies specimens obtained from abnormal and normal colposcopic sites for all patients. The criterion standard of test accuracy was the histologic report of biopsies. We calculated sensitivities, specificities, likelihood ratios, receiver operating characteristic curves, and areas under the receiver operating characteristic curves.


RESULTS
The prevalence of high-grade squamous intraepithelial lesions (HSIL) or cancer was 29.0% for the diagnostic group and 2.2% for the screening group. Using a disease threshold of HSIL, colposcopy had a sensitivity of 0.983 and a specificity of 0.451 in the diagnostic group when the test threshold was low-grade squamous intraepithelial lesions (LSIL), and a sensitivity of 0.714 and a specificity of 0.813 when the test threshold was HSIL. Using the same HSIL disease threshold, in the screening group, colposcopy had a sensitivity of 0.286 and a specificity of 0.877 when the test threshold was LSIL, and a sensitivity of 0.191 and a specificity of 0.961 when the threshold was HSIL. The colposcopy area under the receiver operating characteristic curve was 0.821 (95% confidence interval 0.79-0.85) in the diagnostic setting compared with 0.587 (95% confidence interval 0.56-0.62) in the screening setting. Changing the disease threshold to LSIL demonstrated similar patterns in the tradeoff of sensitivity and specificity and measure of accuracy.


CONCLUSIONS
Colposcopy performs well in the diagnostic setting and poorly in the screening setting. Colposcopy should not be used to screen for cervical intraepithelial neoplasia.


METHODS
II.
Cantor
Scott B
SB
Department of Biostatistics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009, USA. sbcantor@mdanderson.org
Cárdenas-Turanzas
Marylou
M
Cox
Dennis D
DD
Atkinson
E Neely
EN
Nogueras-Gonzalez
Graciela M
GM
Beck
J Robert
JR
Follen
Michele
M
Benedet
J L
JL
D000328:Adult; D003127:Colposcopy; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D065006:Papanicolaou Test; D012680:Sensitivity and Specificity; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000473:pathology; D014626:Vaginal Smears