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NICE Guidance October 2003: NICE recommends that LBC is used as

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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 samples in the cervical screening programme in England and Wales

3 NICE Guidance There is currently insufficient evidence to
recommend one LBC product over another. The NHSCSP and SCW may wish to consider evaluating further different products as the method is introduced.



6 Conventional Smears False Negative Rate of up to 55%
Sampling and interpretative errors Borderline Rates of up to 6.4% 70% are truly negative 30% represent more severe abnormality Inadequate Rates of 9.7%

7 Sources Of False Negatives
Sampling issues (70%) cells not collected on the sampling device cells collected, but not transferred to the slide Interpretative 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 sample containing precancerous cells (red) Non-randomized portion of cells Over 80% of cells discarded Sample may not reflect patient’s actual condition Smear spray-fixed and sent to lab Missing cells, obscuring elements

9 The Solution The Solution The ThinPrep® Pap Test™ Virtually 100% of
cells collected into ThinPrep vial A cervical sample containing precancerous cells (red) Cells immediately preserved and sent to lab Increased opportunity to detect early signs of abnormality Filtration process disperses, randomizes cells More representative and clear thin layer of 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/A Roberts 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 bias Lab / Smear takers Study design bias Split sample / Direct-to-Vial Population bias Self-selecting / Non-screening End point bias Dyskaryosis as ‘surrogate’ / lack of histological confirmation

12 Does LBC decrease inadequate rates?
SurePath cells Thinprep cells Conventional cells?

13 Scottish Pilot Results
Weighted Average (total 30,228) Conventional % ThinPrep % Unsatisfactory Borderline Mild %↑ Moderate Severe % ↑

14 Scottish Pilot Conclusions
No major storage problems Reduced workload for smear takers 349/350 smear takers preferred ThinPrep® Increased productivity in laboratories Sharp reduction in the unsatisfactory rate Less anxiety and discomfort for women More appropriate referrals to colposcopy Allows scope for further developments in the screening programme

15 HPV Triage Negative Borderline Mild dyskaryosis Moderate/severe

16 Vial storage Modular storage units available (File-a-Vial)
150 vial capacity Example: 30,000 samples pa 4 week cycle 2,500 vials 17 units

17 ThinPrep® T2000 Processor

18 ThinPrep® 3000 Processor

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 vial Histology/Cytology correlation rates

21 SurePath SurePath and ThinPrep Differences: Inadequate rates
False negative fraction Detection 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 Adenoca SurePath ThinPrep

25 LBC 5 year conversion timescale is too long LBC is on the way.
Major retraining exercise for labs Benefits in terms of productivity and scope for future developments Good for smear takers and women Issues around sensitivity / specificity / inadequate rates will be answered in long run Expensive solution

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