Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study.
OBJECTIVE
To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, São Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina.


METHODS
A cohort of 12,107 women attending four clinics (Campinas, São Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics.


RESULTS
Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.
Longatto-Filho
Adhemar
A
Instituto Adolfo Lutz and Hospital Leonor M de Barros, São Paulo, Brazil. longatto16@hotmail.com
Maeda
Marina Yoshiê Sakamoto
MY
Erzen
Mojca
M
Branca
Margherita
M
Roteli-Martins
Cecília
C
Naud
Paulo
P
Derchain
Sophie Françoise Mauricette
SF
Hammes
Luciano
L
Matos
Jean
J
Gontijo
Renata
R
Sarian
Luis Otávio
LO
Lima
Temístocles P
TP
Tatti
Sílvio
S
Syrjänen
Stina
S
Syrjänen
Kari
K
D000328:Adult; D001118:Argentina / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D002277:Carcinoma / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D002584:Cervix Uteri / Q000473:pathology; D015331:Cohort Studies; D003584:Cytological Techniques / Q000191:economics / Q000706:statistics & numerical data* / Q000639:trends*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D004847:Epithelial Cells; D005260:Female; D006801:Humans; D007843:Latin America / Q000453:epidemiology; D008403:Mass Screening; D065006:Papanicolaou Test; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D014626:Vaginal Smears / Q000191:economics / Q000706:statistics & numerical data* / Q000639:trends*