Quality Assurance in Cervical Cytology

Transcription

1 Quality Assurance in Cervical Cytology Shaira Sahebali 10 th June 2017 Overview l Definition l Application l Measurements l Achievement of required level of competence l External quality assessment 1

2 Definition l To attain and sustain a certain level of technical and diagnostic skills l Constant improvements in timing, performance and achievements of uniform quality l Systematic monitoring of results and parameters to detect, control and prevent mistakes l Histology AND cytology 2

3 How to evaluate? l Non-official g Internal consult: What do you think? g External consult g Statement in protocol = semi-official l Official g BELAC: Belgian Accreditation Institute 2006 g JCI: Joint Commission International 1994 g Other 3

4 Level of competence l Where do I want to go? g Minimal requirements ISO g Additional l Hospital l Clinicians l Department l How do I get there? l How do I stay there? Stages of quality control 4

5 Application on diagnostic chain l Pre-analysis g Clinical condition woman l Day of cycle l Post partum l Infections g Sample collection l Anatomy l Method & training of sample taker - Incomplete sampling - Loss of diagnostic cells Application on diagnostic chain l Pre-analysis g Clinical administration l Labeling sample l Order form g Lab administration l ID l Clinical information l Match with sample 5

6 Application on diagnostic chain l Analysis preparation technique g Laboratory procedures l Conventional LBC l Automation l Training lab personnel g Equipment l Preparation of slide l Computer-assisted processing/ screening g Staining and other tests l PAP, modifications l Immunocytochemistry l HPV Application on diagnostic chain l Analysis - diagnostics g Primary screening l Manual computer-assisted l Training CT, pathologist g Interpretation l Correlation between viewers (peer review) l Cytology versus biopsy g Reporting (post-analysis) l Bethesda, PAP, others l Management advice, explanatory notes 6

7 Quality Assessment Cycle items? item item Why does QA matter? l Avoid/ reduce faults g False negatives, false positives g Inadequate follow up g Unnecessary investigation and treatment l Uphold effectiveness of screening 7

8 Where can things go wrong? l Administrative g Correct identification g Data entry g Several links in the chain l Technical g # cells on slide g Staining; other reagents g Imaging Technical issues 8

9 Technical issues Where can things go wrong? l Diagnostics g Environment l Equipment l Space l Peace and quiet g Adequacy l # cells l Transformation zone l Feedback to clinician 9

10 Where can things go wrong? l Diagnostics g Search & Identify l Habituation, distraction l Identification of cells l Overconfidence, anxiety l Too many, too fast g Reporting l Training, experience l Confidence l Workload What to evaluate? l Technique l Diagnostics g Proficiency testing g Reporting l Accreditation l Laboratory organization l Performance 10

11 Measurement of results Test pos Disease No Disease Total RP (real positive) FP (false positive) Total # positive tests Pos.pred.value= RP/ (RP+FP) Test neg FN (false negative) RN (real negative) Total # negative tests Neg.pred.value= RN/ (RN+FN) Total Total # disease Total # no disease All= RP + FP + FN + RN Sens= RP/ (RP+ FN) Spec= RN/ (RN + FP) Pre-test Probability= (RP + FN)/ (All) Measurement of results l False positive (cytology > biopsy) g Lesion regressed g Lesion very small g Lesion not in biopsy g Cytological abnormalities overrated l False negative (cytology < biopsy) g Lesion not in cytology sample g Abnormal cells not on slide g Abnormal cells not recognized or interpreted wrong 11

12 Measurement of results l Threshold # false negatives g # ASC/ASC-US/ASC-H or LSIL g Comparison individual versus every-one g Document beforehand l Required level of competence l Measurements l Corrective actions l Positive predictive value l Referral value Measurement of results l Threshold # false negatives g # ASC/ASC-US/ASC-H or LSIL l ASC= 3-5%, of which ASC-H= 10% l ASC/SIL= 2-3:1 l hrhpv+ in ASC-US= 30%-50% g Ratio hides double faults g Ratio CT differs from CT + Path g Higher CT ratio yields better sensitivity 12

13 Achievement of required competence l During diagnostics g Review (10%) NILM, at risk cases g Pre- or review all slides l Rapid l CT or computer g Correlation CT supervisor (CT or pathologist) g 2nd reading 13

14 Achievement of required competence l After first diagnostics g HSIL review: History of 5 years l By various persons l Blind l Index case in test series g Correlation cytology histology l Collaboration with dept of gynecology for additional information g Correlation cytology HPV l Collaboration with dept of molecular biology Achievement of required competence l Periodical outside diagnostics g Internal IQA test g Compare within screening program l Correlation distribution diagnoses - Other labs - Epidemiology: Belgian Cancer Registry l Correlation HPV results l Patient history g Internal continuing education l Books, journals, slides 14

15 Achievement of required competence l Work meeting individual evaluation g Feedback diagnostics g Workload, reading speed, TAT l How to organize work g Levels of CT CT supervisor Head CT g Pathologists g Head of department l Ergonomics g Mens Sana in Corpore Sano Laboratory organization Head Pathologistsupervisors Head CT CT experts CT pool 15

16 Internal Quality Assessment l Technical check-ups g Personnel l Technical l Administration g Equipment l Diagnostics g Compose your own test series g Histologically proven if possible g All CTs and screening pathologists l Primary l Secondary 16

17 l If the number of samples decreases, maintenance of competence becomes more difficult l Triage sifts out the more difficult cases l How does vaccination influence this system? 17

18 External continuing education l Review sessions l Workshops, courses l Students, CTs and pathologists (intraining) l In group and individual The ideal external assessment 18

19 External Quality Assessment l Proficiency testing g National: WIV/ ISSP g Europe: AfaQap, SKML, UKAS g Other: CAP l Accreditation g BELAC g Other g ISO External Quality Assessment l How and what? g Technical g Diagnostics l Colleagues, guidelines l Evaluate slides, photos, scans l Depends in part on used technology/ guidelines l Educational or testing of expertise g Laboratory organization l Work practice l Ergonomics 19

20 CAP l Participants provide cases to archive l Conventional, SP, TP, mix l Manual screening l Response by fax or website l Mandatory test in USA g Only miss 1/10 g NO HSIL miss! Ypermangroup l Participants provide TP cases l Slides are imaged l Screen by reviewscope (or manual) l Response via website l Evaluation report l Yearly meeting g Diagnosis: absolute and corrected g Management: follow up advice g Technique/ use of scope 20

21 Reviewscope Yperman scoring algorithm ANTWOORD / DIAGNOSE NILM AGC/ASCUS LSIL HSIL ADCA/PCC NILM AGC/ASCUS LSIL HSIL ADCA/PCC

22 QUATE aptitude test l Quality Assurance, Training and Examination l International (EU) test for CTs who fulfill national accreditation criteria l Conventional and LBC l Written: 50 MCQ l Practical: screen 16 slides The ideal test l Cases of doubt; ASC-US? l NILM without proof? l How many cases in test series? l What is included in test series? l How many mistakes are allowed? g # g weight 22

23 Remember l Broader context g Clinician, molecular biologist g Hospital g Screening program l Important g HPV primary screening g Follow up References l g QA course l g European screening guidelines l Auger M. Cancer Cytopathol 2014 Jan l Cibas E.S. Am J Clin Pathol 129:

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