Presentation on theme: "NICE Guidance October 2003: NICE recommends that LBC is used as"— Presentation transcript:
1 LBC – Sink or Swim? Thames Valley Cytology Society Bedford 24th June 2004
2 NICE Guidance October 2003: NICE recommends that LBC is used as the primary means of processing samplesin the cervical screening programme inEngland and Wales
3 NICE Guidance There is currently insufficient evidence to recommend one LBC product overanother.The NHSCSP and SCW may wish toconsider evaluating further differentproducts as the method is introduced.
6 Conventional Smears False Negative Rate of up to 55% Sampling and interpretative errorsBorderline Rates of up to 6.4%70% are truly negative30% represent more severe abnormalityInadequate Rates of 9.7%
7 Sources Of False Negatives Sampling issues (70%)cells not collected on the sampling devicecells collected, but not transferred to the slideInterpretative issues (30%)abnormal cells present on slide but either not seen or misinterpreted
8 The Problem The Problem The Conventional Cervical Smear Non-randomized A cervical samplecontaining precancerouscells (red)Non-randomizedportion of cellsOver 80% ofcells discardedSample may notreflect patient’sactual conditionSmear spray-fixedand sent to labMissing cells,obscuring elements
9 The Solution The Solution The ThinPrep® Pap Test™ Virtually 100% of cells collected intoThinPrep vialA cervical samplecontaining precancerouscells (red)Cells immediatelypreserved andsent to labIncreasedopportunity todetect early signsof abnormalityFiltration process disperses,randomizes cellsMore representativeand clear thin layerof cells
10 Evidence Base Clinical Validation ThinPrep® Improvement Patients LSIL+ HSIL+ S.Q.Split-Sample Lee et al. 6, % 36% 54%Corkill et al. 1, % 54% N/ARoberts et al. 81, % 15% 91%Direct-to-Vial Scottish Pilot 30,228 92% 84% 76%Diaz-Rosario 56,339 72% 103% ???Papillo et al. 8, % 55% 52%Weintraub et al. 18, % 94% 93%Bolick 10, % 173% 70%Johnson et al % 125% 41%Guidos/Selvaggi 9, % 233% 97%Quddus 14, % 35% 28%Hornish 30, N/A 83% N/A>60 peer reviewed international publications from 4 Continents
11 Does LBC increase sensitivity? Educational biasLab / Smear takersStudy design biasSplit sample / Direct-to-VialPopulation biasSelf-selecting / Non-screeningEnd point biasDyskaryosis as ‘surrogate’ / lack of histological confirmation
12 Does LBC decrease inadequate rates? SurePath cellsThinprep cellsConventional cells?
13 Scottish Pilot Results Weighted Average (total 30,228)Conventional % ThinPrep %UnsatisfactoryBorderlineMild %↑ModerateSevere % ↑
14 Scottish Pilot Conclusions No major storage problemsReduced workload for smear takers349/350 smear takers preferred ThinPrep®Increased productivity in laboratoriesSharp reduction in the unsatisfactory rateLess anxiety and discomfort for womenMore appropriate referrals to colposcopyAllows scope for further developmentsin the screening programme
19 SurePath Why I like the SurePath Liquid-Based PAP Test David R Bolick RPS Sandy, Utah
20 SurePath SurePath and ThinPrep Similarities: Diagnostic rates Detection rates of HPV from vialHistology/Cytology correlation rates
21 SurePath SurePath and ThinPrep Differences: Inadequate rates False negative fractionDetection of abnormalities in clusters
22 SurePath SurePath and ThinPrep Inadequate rates:
23 SurePath SurePath and ThinPrep False negative fraction: LSIL % HSIL % SurePath screened TWICE ; ThinPrep screened ONCE
24 SurePath SurePath and ThinPrep Abnormalities in clusters: AGUS Endom AdenocaSurePathThinPrep
25 LBC 5 year conversion timescale is too long LBC is on the way. Major retraining exercise for labsBenefits in terms of productivity and scope for future developmentsGood for smear takers and womenIssues around sensitivity / specificity / inadequate rates will be answered in long runExpensive solution
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