Liquid-Based Cytology: Evaluation of Effectiveness, Cost-Effectiveness, and Application to Present Practice

Abstract

This article reviews the data available as of 2004 on the effectiveness and cost-effectiveness of cervical screening with the two available cytologic methods, the conventional Papanicolaou (Pap; CP) smear and liquid-based cytology (LBC), and discusses the application of LBC to current practice. The majority of LBC studies are on the ThinPrep Pap Test (CYTYC, Boxsborough, MA) and the remainder are on SurePath (TriPath, Burlington, NC), which was previously known as AutoCyte Prep. LBC identified more low-grade squamous intraepithelial lesion (LSIL) Pap test results compared with paired conventional cytology in 17 of 21 ThinPrep and 9 of 12 SurePath “split-sample” studies considered to fulfill the criteria for inclusion in the British NHS Health Technology Assessment (HTA) evaluation of cervical cytology. In four of the six recent ThinPrep and one of two SurePath split-sample studies, more high-grade squamous intraepithelial lesion-positive (HSIL+) results were identified by LBC than by CP. All 15 “direct-to vial studies” meeting HTA criteria reported more LSIL+ results for LBC compared with CP, and all eight of the direct-to-vial studies reporting HSIL+ results separately showed increased detection of high-grade cytology interpretations. Fifteen studies met the criteria for evaluating sensitivity and specificity. Aggregate sensitivity for the CP was 71.5% and for LBC was 80.1%. Indirect comparisons of the two LBC methods did not detect a difference in sensitivity, and a meta-analysis of the six studies comparing specificity between CP and LBC found no difference. Other capabilities of LBC are improved specimen adequacy and the ability to do ancillary testing out of the liquid-based vial. In cost-effective analyses based on models of disease natural history and/or the clinical effectiveness of each screening modality, screening with CP was always dominated by screening with LBC. Primary cervical screening guidelines issued by the American Cancer Society in 2002 recommend repeating the cytology biannually if liquid-based and annually if conventional. The gain in sensitivity, apparent cost-effectiveness, and advantage of having a representative specimen for ancillary testing, support the use of LBC.

Liquid-based and conventional cytology for bronchial washings/bronchoalveolar lavages in the diagnosis of malignancy - An institutional experience

“…[8910] Few researchers have applied LBC technology to BW/lavage specimens and only limited data on its utility is available in the literature.…”

Performance of the Cellslide^® automated liquid-based cytology system amongst HIV-positive women

“…Results on the cost-effectiveness of LBC are conflicting, depending on whether studies found improvements in the adequacy or detection of abnormality rates. A study by Taylor et al 20 found that a commonly used LBC product reduced the number of inadequate smears but did not improve detection of histology-confirmed disease (cervical intraepithelial neoplasia grade 1 or worse) and therefore concluded that the increased cost does not justify the implementation of LBC. In contrast, a review by Cox 21 showed that LBC was cost-effective.…”

The Effect of Progesterone Only Contraception on the Accuracy of Cervical Cytologic interpretation

“…Specifically, multiple studies have noted the strong positive association between cytologic screening and histologic diagnosis in detecting cervical dysplasia. 13,14,125 There was a significant association between cytology and histology (p = .019) among women who had no progesterone exposure (Table 4-3). This again would be expected, based on what is known in the literature.…”

“…The ASCUS/LSIL Triage study (or "ALTS," as it is referred to) of 1995-2001 set the standard for much of what is known about the relationship between abnormal cytology and subsequent histology. 13 Treatment of cervical dysplasia and neoplasia is determined by the histology result, thus clinicians and researchers must understand the relationship between cytology and histology. Further, factors that may affect that relationship need to be well understood.…”

“…12 A 1999 Agency for Health Care Policy Research review set Pap test sensitivity within a range of 51-66% for detection of all grades of cervical intraepithelial neoplasia (CIN) and slightly higher for high grade lesions (not exceeding 70-80%). 13 Uyar et al (2003) noted cytologic screening to have a high sensitivity from 55% to nearly 100% for detecting squamous cell neoplasia. 14 Cytologic screening relies on the subjective interpretation of the sample by a pathology professional.…”