Conventional Pap Smear and Liquid-Based Cytology as Screening Tools in Low-Resource Settings in Latin America

University of Turku, Turku, Varsinais-Suomi, Finland
Acta Cytologica - ACTA CYTOL 09/2005; 49(5):500-506. DOI: 10.1159/000326195

ABSTRACT 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 Lugols Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, Sao Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina. Study Design A cobort of 12,107 women attendingfour clinics (Campinas, Sao Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive witb any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance cbaracteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10, 240), and LBC (Autogte (R) PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n = 320, and DNA-Citoliq (R) [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 LRC 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 (R) PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NVP) 88.8%. DNA-Citoliq (R) detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV40.0% 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. Conclusion In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte (R) PREP had 100% SP and PPV in detecting CIN 3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCH.

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    ABSTRACT: We sought to test the diagnostic efficacy of a low-cost, liquid-based cervical cytology that could be implemented in low-resource settings. A prospective, split-sample Pap study was performed in 595 women attending a cervical cancer screening clinic in rural El Salvador. Collected cervical samples were used to make a conventional Pap (cell sample directly to glass slide), whereas residual material was used to make the liquid-based sample using the ClearPrep method. Selected samples were tested from the residual sample of the liquid-based collection for the presence of high-risk Human papillomaviruses. Of 595 patients, 570 were interpreted with the same diagnosis between the 2 methods (95.8% agreement). There were comparable numbers of unsatisfactory cases; however, ClearPrep significantly increased detection of low-grade squamous intraepithelial lesions and decreased the diagnoses of atypical squamous cells of undetermined significance. ClearPrep identified an equivalent number of high-grade squamous intraepithelial lesion cases as the conventional Pap. High-risk human papillomavirus was identified in all cases of high-grade squamous intraepithelial lesion, adenocarcinoma in situ, and cancer as well as in 78% of low-grade squamous intraepithelial lesions out of the residual fluid of the ClearPrep vials. The low-cost ClearPrep Pap test demonstrated equivalent detection of squamous intraepithelial lesions when compared with the conventional Pap smear and demonstrated the potential for ancillary molecular testing. The test seems a viable option for implementation in low-resource settings.
    Journal of Lower Genital Tract Disease 11/2013; 18(2). DOI:10.1097/LGT.0b013e31829aa052 · 1.21 Impact Factor
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    ABSTRACT: Objective To assess impact on interlaboratory agreement of 2 optional modes to convert Papanicolaou classification to Bethesda System (TBS) and demonstrate effect of verification bias correction on test performance in the New Independent States of the former Soviet Union (NIS) cohort study. Study Design Conventional Pap smears were classified in NIS laboratories and rescreened in a reference center (RC) using modified Papanicolaou classification. Two optional methods (TBS1, TBS2) were used to convert original classification to TBS. All classifications were tested for interlaboratory agreement and performance indicators with and without verification bias correction. Results Interlaboratory agreement of original classification was fair with regular kappa, but substantial with weighted kappa. TBS1 option (Class 2 in atypical squamous cells of undetermined significance [ASCUS]) did not remedy this limited reproducibility. When Class 2+ (borderline dyskaryosis) was used as cutoff for ASCUS (TBS2), interlaboratory agreement was upgraded to moderate and almost perfect. Test performance was significantly different between NIS and RC only for TBSI option with ASCUS cutoff, RC showing better sensitivity/specificity balance by area under receiver operating characteristic curve test. Conclusion In convening traditional classification to TBS, selection of appropriate equivalents to TBS categories has a major impact on interlaboratoty agreement and performance indicators. (Acta Cytol 2009;53:548-557)
    09/2009; 53(5):548-557. DOI:10.1159/000325383
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    ABSTRACT: Objective: This study sought to ascertain the significance of augmented high-grade squamous intraepithelial lesion (HSIL) detection by Pap test using both conventional smear and liquid-based cytology (LBC) in a high-risk population. Study Design: We conducted a direct-to-vial study to compare the diagnostic performance of Pap smear versus LBC in a high-risk population of women referred for colposcopy at a gynecologic ambulatory clinic at the Barretos Cancer Hospital in Brazil during 2011. Results: The detection of both low-grade squamous intraepithelial lesions (LSILs) and HSILs was significantly greater (p = 0.04 and p = 0.033, respectively) in the LBC arm [84 LSIL cases (5.7%) and 148 HSIL cases (10.1%)] than in the conventional smear arm [66 LSIL cases (4.1%) and 126 HSIL cases (7.9%)]; however, no differences were found for invasive squamous carcinoma or adenocarcinoma (p = 0.678). Of 3,071 women who were examined cytologically (1,604 conventional preparations and 1,467 LBC) and colposcopically, biopsies were available for 279 conventional preparations (17.6%) and 325 LBC preparations (22.2%). No significant differences were found between the methods with respect to diagnostic performance. Conclusion: LBC was significantly superior to conventional smears for the detection of LSILs and HSILs, but these results did not influence biopsy confirmation. Both methods showed similar performances with high positive predictive values but very low sensitivities. © 2013 S. Karger AG, Basel.
    Acta cytologica 01/2013; 57(5):489-94. DOI:10.1159/000351789 · 1.56 Impact Factor