Accuracy of liquid based versus conventional cytology: overall results of new technologies for cervical cancer screening: randomised controlled trial.
OBJECTIVE
To compare the accuracy of conventional cytology with liquid based cytology for primary screening of cervical cancer.


METHODS
Randomised controlled trial.


METHODS
Nine screening programmes in Italy.


METHODS
Women aged 25-60 attending for a new screening round: 22 466 were assigned to the conventional arm and 22 708 were assigned to the experimental arm.


METHODS
Conventional cytology compared with liquid based cytology and testing for human papillomavirus.


METHODS
Relative sensitivity for cervical intraepithelial neoplasia of grade 2 or more at blindly reviewed histology, with atypical cells of undetermined significance or more severe cytology considered a positive result.


RESULTS
In an intention to screen analysis liquid based cytology showed no significant increase in sensitivity for cervical intraepithelial neoplasia of grade 2 or more (relative sensitivity 1.17, 95% confidence interval 0.87 to 1.56) whereas the positive predictive value was reduced (relative positive predictive value v conventional cytology 0.58, 0.44 to 0.77). Liquid based cytology detected more lesions of grade 1 or more (relative sensitivity 1.68, 1.40 to 2.02), with a larger increase among women aged 25-34 (P for heterogeneity 0.0006), but did not detect more lesions of grade 3 or more (relative sensitivity 0.84, 0.56 to 1.25). Results were similar when only low grade intraepithelial lesions or more severe cytology were considered a positive result. No evidence was found of heterogeneity between centres or of improvement with increasing time from start of the study. The relative frequency of women with at least one unsatisfactory result was lower with liquid based cytology (0.62, 0.56 to 0.69).


CONCLUSIONS
Liquid based cytology showed no statistically significant difference in sensitivity to conventional cytology for detection of cervical intraepithelial neoplasia of grade 2 or more. More positive results were found, however, leading to a lower positive predictive value. A large reduction in unsatisfactory smears was evident.


BACKGROUND
Current Controlled Trials ISRCTN81678807 [controlled-trials.com].
Ronco
Guglielmo
G
Unit of Cancer Epidemiology, Centre for Cancer Prevention, Via S Francesco da Paola 31 10123 Turin, Italy. guglielmo.ronco@cpo.it
Cuzick
Jack
J
Pierotti
Paola
P
Cariaggi
Maria Paola
MP
Dalla Palma
Paolo
P
Naldoni
Carlo
C
Ghiringhello
Bruno
B
Giorgi-Rossi
Paolo
P
Minucci
Daria
D
Parisio
Franca
F
Pojer
Ada
A
Schiboni
Maria Luisa
ML
Sintoni
Catia
C
Zorzi
Manuel
M
Segnan
Nereo
N
Confortini
Massimo
M
D000328:Adult; D003584:Cytological Techniques / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000592:standards*; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control* / Q000821:virology; D014626:Vaginal Smears / Q000592:standards; D002578:Uterine Cervical Dysplasia / Q000517:prevention & control* / Q000821:virology