Cervical Cancer : Pap smear

Transcription

1 Taking a PAP SMEAR

2 Cervical Cancer : Pap smear George N Papanicolaou introduced cervical cytology in clinical practice in 1940 In 1945, PAP smear was endorsed by American cancer society as an effective method for prevention of cervical cancer Many countries now have National cervical screening programs

3 Indian scenario Commonest cancer in women in India Major cause of deaths in women due to cancer Usually diagnosed at advanced stage No National program Uniformly low incidence of cervical screening in India (6% in rich & 4% in poor)

4 Histological Types 30 Squamous Cell Carcinoma : 80-95% Adenocarcinoma : 5-20% Other : Clear cell, sarcomas

5 Transformation zone Cervix develops from 2 embryonic sites * from Mullerian duct - lined by columnar epithelium * from urogenital plate - lined by stratified squamous epithelium Point at which columnar and squamous epithelium meet is called as original squamo-columnar junction

6 Transformation zone Under influence of estrogen, original SCJ moves onto the portio. Exposure of delicate columnar cells to vaginal environment leads to squamous metaplasia. Transformation zone - - Area of squamous metaplasia - Area between original and new SCJ

7 Transformation zone

8 Transformation Zone -TZ Exposure of TZ to carcinogens begins the process of intraepithelial neoplasia While exact role of carcinogens in this process remains poorly understood, it is clear that HPV and cigarette smoking can cause dysplasia at the TZ 95% of cervical cancers develop in TZ Important to take sample from TZ

9 Transformation Zone Transformation zone may not be viewed during routine speculum examination

10 Why cervical screening is a feasible and useful strategy? Relative accessibility of cervix to take the smear Long natural history of cervical carcinogenesis Relative conservative treatment for premalignant lesions Cost effectiveness3

11 PAP Smear PAP smear sampling of cervix involves scraping of cervical surface and a portion of non visualised cervical canal using various sampling devices

12 Significance of Pap smear Detect precancerous & invasive cancer cervix cases in early stages Positive screeners can be selected for selective tests and management With treatment, progression of disease is halted. Thus morbidity associated with advanced cancer decreases Mortality reduces by %. Helps us to study natural history of disease.

13 Cervical Cancer : Pap smear Early detection of pre-malignant lesions by Pap smears prevent at least 70% of potential cervical cancers.

14 Of the 30% who actually develop cervical cancer: 8% elude cytological detection - imperfections in cytological technology - biologic behavior of malignant lesions 22% represent women who develop cervical cancer because of failure to regularly seek Pap smears => women whose cancers could have been prevented with early detection and treatment.

15 How to take a Pap Smear? Proper technique is very important More problems are due to improper sampling than screening Not to be collected during menses Avoid vaginal contraceptives, vaginal medications for at least 48 hrs before taking smear Abstinence for 24 hrs Postpartum smear should be taken only after 6-8 weeks of delivery

16 How to take a Pap Smear? Patient in dorsal position Good illumination is necessary Cusco s speculum is inserted to visualise & fix the cervix Inspection of cervix done & findings are noted Ayres spatula is inserted first. It is placed at cervical os so that longer end goes into cervical canal and smaller end rests on ectocervix

17 How to take a Pap Smear? Spatula is rotated through 360 degrees maintaining contact with ectocervix Do not use too much force [bleeding /pain] Do not use too less force [inadequate sample] Sample is smeared evenly on the slide and fixed immediately Both sides of spatula are to be smeared

18 How to take a Pap Smear? Endocervical sample is collected using an endocervical brush Insert the cytobrush into canal, so that last bristles of brush are visible Rotate the brush through 180 degrees. [more rotations increase the chance of bleeding] Sample is rolled on the slide and fixed.

19 Fixation of smear Fixation is done immediately with fixative like 95% alcohol or cytofix spray to avoid air drying Spray should be kept at 10 inches, to avoid destruction of cells by propellent in the spray Smear should monolayer for proper penetration of cell surface by fixative

20 How to take a Pap Smear? Slide should be labeled properly with patients name, identification no. and details Detailed history and clinical examination findings are to be mentioned Patient details and clinical findings are to be maintained in a register Advice is given regarding further follow up and treatment

21 Systems for cervical cytology reporting George N Papanicolaou (1954) 5 classifications based on certainty of finding malignant cells Descriptive system WHO - (1968) based on morphologic criteria included mild, moderate, severe dysplasia and Ca In Situ Richart CIN based on histologic diagnosis

22 Systems for cervical cytology reporting Bethesda system TBS (1988) National cancer institute revised in 1991 and 2001 Adequacy of smear must be determined before reporting Smear is adequate when - Patient identification - adequate clinical history

23 Bethesda system Interpretable cellular cytology not obscured by inflammation, debris, blood, drying not scanty smear Adequate sampling from transformation zone presence of at least 2 clusters of well preserved endocervical cells or metaplastic cells

24 Bethesda system Results : Within normal limits ( WNL ) Benign cellular changes - this term was removed and group was included in WNL in 2001 Reactive or Reparative changes seen with atrophy, inflammation, surgery, radiation, IUCD, tampoons Infections trichomoniasis, fungal, bacterial, HSV.

25 Bethesda system - results Epithelial cells abnormalities Squamous cells ASCUS ASCUS-H - suggestive of high grade lesion LSIL - changes associated with HPV, atypical changes, mild dysplasia/ CIN1 HSIL moderate to severe dysplasia / CIN2, 3 and Ca In Situ HSIL where invasion cannot be ruled out Squamous cell carcinoma

26 Bethesda system Results : Glandular cells AGUS (Endocervical, endometrial) Adenocarcinoma (endocervical, endometrial, extrauterine) Other malignant neoplasms

27 Normal cervix-cytology Squamous cells Exfoliated indivisual cells Navicular in shape with abundant cytoplasm and small, dark, round /oval, pyknotic nuclei Glandular cells Many times seen in clumps - linear or honeycombed pattern. Slightly larger and basal nuclei

28 Cervical cytology - Inflammation Interpretation difficult due to inflammatory background Lot of neutrophils and blood can obscure cellular details

29 Low grade lesions

30 High grade lesions High grade squamous lesion High grade glandular lesion

31 Abnormal Pap smear- HPV Peripherial condensation of cytoplasm - wire looping effect Koilocyte

32 PAP Descriptive CIN Bethesda Class-1 negative negative WNL Class 2 Inflammatory, squamous, koilocytic atypia Reactive, reparatative changes, ASCUS, LSIL(HPV) Mild dysplasia CIN1 LSIL(HPV) Class 3 Moderate dysplasia Severe dysplasia CIN2 CIN3 HSIL HSIL Class 4 Ca In Situ CIN3 HSIL Class 5 Invasive Invasive Invasive

33 PAP smear Single test will not detect cervical abnormality but with 3 negative tests there is less than 1% chance of cervical abnormality Conventional cytology has specificity of 98% and sensitivity of 51%.

34 PAP Smears - Limitations Low sensitivity 51% False negative rates are due to faulty sampling, improper fixation or interpretation problems Large group population & high risk group screening not possible No consensus regarding testing

35 Pap smear as screening method New guidelines Target group - All women aged yrs who have ever had sex Timing of Initial Screening - Initial screening at age of 21 years or within 3 years of sexual activity ACOG Guidelines-(Aug2003), American Cancer Society (Nov 2002) and U.S. Preventative Services Task Force (Jan 2003)

36 Pap smear - guidelines Screening interval - yearly till the age of 30 then 3 yearly When to End Screening - After 70 yrs - Post Hysterectomy - done for benign lesions - previous 3 normal PAP reports - confirmed complete removal of cervical epithelium

37 Pap smear - guidelines In high risk group after treatment for CIN every 3 monthly for 2 years every 6 monthly for 3yrs Yearly thereafter Women who had hysterectomy for CIN, it is necessary to do vault smears In women who received vaccination against HPV, it is necessary to continue screening

38 Liquid Based Cytology To improve results of PAP newer techniques like liquid based cytology are recommended Cells are obtained with a broom, then the head is broken off in to a vial containing preservative fluid In the laboratory the sample is spun to remove obscuring material It gives clearer image, no cell clumps It will assist in future automated reading

39 Liquid Based Cytology Several slides can be prepared from one smear Chlamydia, HPV testing can be done at later date Reduces the incidence of inadequate and repeat smears

40 Cancer Cervix IS PREVENTABLE, IF Detected EARLY!!!!!!!!! Thank You