Liquid-based cytology

(1)

Liquid-based cytology

Claire Bourgain

UZBrussel

z

LBC for

LBC for gynaecological

gynaecological cytology has been introduced in Belgium a

cytology has been introduced in Belgium a

decade ago

z

There is no consensus

J

On performance compared to conventional cytology

J

On price/quality assessment

J

On technical recommendations for quality assessment, review

techniques, reflex HPV testing, ancillary

techniques, reflex HPV testing, ancillary stainings

stainings

z

There are no randomized studies comparing LBC to LBC

z

Topic:

Surepath vs Thinprep

comparison

J

For technical issues

J

For cytological criteria

(2)

Bourgain, BVKC-SBCC 6 december 2008 3

LBC in Belgium

Cervical cancer screening by

cytology

Conventional or

validated LBC technique

HPV for triage of ASC-US

FDA approved

z

ThinPrep

®

J

Filtration and collection of vacuum

-

packed cells on a membrane and

transferring to the glass slide

z

Surepath

®

J

Centrifugation and sedimentation through a density gradient

Not FDA approved

z

Cytoscreen

®

z

Turbitec

®

z

Cellslide

®

z

Papspin

®

J

Centrifugation and sedimentation by manual techniques

(3)

LBC

Conventional

Sampling

manual

cervexbrush

or other

Fixation

before smear

after smear

liquid medium

spray or alcohol

standard

not standard

pooled cells

only the smeared cells

Smear

automatically

manual

thin

layer

variable thickness

selected population

no cell selection

Staining

possibly automatic

lab function

Reading

experience needed

short time

normal time

Ancillary

standard

possible

technologies (HPV)

Liquid-based versus conventional cytology

(4)

Liquid-based versus conventional cytology

Arbyn et al, Obstet Gynecol, 2008

64,6/71,3

78,8/81,2

97/96,7

Specificity

90,4/88,2

79,1/75,6

57,1/55,2

Sensitivity

ASC-US+

LSIL+

HSIL+

LBC/Conv

%

Randomized controlled studies

Colposcopy and histology as golden standard

No improvement of HSIL detection by LBC

Colgan et al, Cancer, 2008

Cytology results for LBC

(5)

Colgan et al, Cancer, 2008

Surepath® versus Conventional

Cytology results for LBC

Schledermann et al, Diagnost Cytopath, 2006

Cytology results for LBC

(6)

ThinPrep® vs Conventional

(7)

Cytology results for LBC

Nance, Diagnost Cytopath, 2008

ThinPrep® versus Surepath® versus Conventional

(8)

Liquid-based versus Conventional

z

Improvement of smear quality

z

Increased diagnosis of ASC-US and LSIL

z

No significant increase of HSIL detection

z

Insufficient data comparing the performance

of both FDA approved techniques

Liquid-based FDA-approved devices

(9)

ThinPrep

®

SurePath

®

Fixation

PreserveCyt

PreserveCyt fluid

fluid

CytoRich

CytoRich fluid

fluid

Storage

6 month 15

6 month 15-

-30

30°

°C

C

Broom

Rotate clockwise 5 times

Vial

Push broom to bottom, swirl

Drop broom in solution

discard the broom

Storage

6 weeks at 4

6 weeks at 4°

°C

C

4 weeks room temperature

Cell sample collection

Surepath®

(10)

ThinPrep

®

SurePath

®

PreserveCyt

fluid

CytoRich

fluid

Methanol

Ethanol

No vortex

Vortex

1slide

48 slides

No gradient centrifugation

Gradient centrifugation

Filter

No filter

No sedimentation

Sedimentation

No staining

Staining

Preparation technique

Adequacy assessment

Bethesda 2001 for LBC preparations

5000 evaluable cells

10 endocervical or metaplastic cells

13mm

20mm

Surepath®

(11)

Less obscuring cells

Epithelial cells are slightly smaller

More single cells

TBS: LSIL nuclei enlargement of 3 x

Decreased

cytoplasmic

area in HSIL

LBC:

Nuclei enlarged 2

-

1,5 x

Statistically decreased

cytoplasmic

area 2

-

3 x LSIL

-

HSIL

N/C ratio increase from 33% to 50%

Caveat:

bland

dyskaryosis

Cytological criteria of LBC

(12)

NILM, Clue cells

(13)

NILM, EMC

(14)

LSIL, ThinPrep®

(15)

HSIL

(16)

AIS, Surepath®

Possible on both

ThinPrep

and

SurePath

samples

Should include positive and negative controls

J

From test kit

J

From own samples

Causes for rejection

J

Inadequate specimen according to cytological evaluation

J

Improperly labeled specimen or name discrepancies

J

Specimen leaked in transit

J

Insufficient quantity of specimen

J

Specimen collected on male patients

J

Specimen older than 21 days in

Specimen older than 21 days in SurePath

SurePath fixative

fixative

J

Specimen older than 3 months in

Specimen older than 3 months in PreservCyt

PreservCyt fixative

fixative

J

Specimen collected in vial that expired according to label

(17)

Topoisomerase

IIA and Mini chromosome maintenance protein 2

Immunocytochemical

Immunocytochemical assay with a cocktail of monoclonal

assay with a cocktail of monoclonal

antibodies on a blank slide generated with BD

antibodies on a blank slide generated with BD SurePath

SurePath®

®

system

Positive signal is a nuclear staining

Responsible for DNA integrity, accumulate in cells after

neoplastic

neoplastic transformation and aberrant entry in S

transformation and aberrant entry in S-

-phase

phase

TOP2A: unravels excessive DNA coiling in transcription and repli

TOP2A: unravels excessive DNA coiling in transcription and replication

cation

MCM protein: forms a complex at DNA replication initiation and

elongation, maintains genome stability in S

elongation, maintains genome stability in S-

-phase

phase

Ancillary techniques- Pro ExC®

Ancillary tehcniques ProEx®C

(18)

Conclusions

z

Criteria for Thinprep® and Surepath®

J

Similar cytological criteria can be applied

J

Criteria do not differ from conventional cytology

z

Specific technical recommendations apply for

J

Sampling and sample preservation

J

Reflex HPV testing

J

Ancillary stainings

z

No

significant increase of HSIL detection

J

BUT

: no prospective comparative studies

z

Insufficient data for application of rapid review

techniques