screening for cervical cancer by visual inspection techniques
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Screening forCervical Cancer
byVisual Inspection Techniques
Dr Aruna BatraVMMC & SJH
Cervical Cancer- Facts
• A significant public health problem• 2nd commonest cancer in ώ worldwide• Annually 3,70,000 new cases of cervical
cancer, 80% in developing countries• Leading cause of death in developing countries,
often killing women at young ages
Cervical Cancer- Facts
• Cause: virtually all cases of cervical cancer are caused by persistent cervical infection with some types of Human Papilloma Virus (STI)
• Develops slowly, has a detectable and treatable precancerous stage
• Preventable disease
Cervical Cancer- Why preventable?
Easy accessibility of Cx & TZ
Natural History of Cervical Cancer
HPV-related Changes
Normal Cervix
Low-Grade SIL
High-Grade SIL
Invasive Cancer
HPV Infection
CofactorsHigh-Risk HPV
About 60% regress within 2-3 yrs
15% progress êin 3-4 yrs
30 - 70% progress êin 10 yrs
Cervical Cancer- Risk Factors
• Early age at marriage• Multiple sexual partners• Sexually transmitted infections• Poor socio-economic status• Smoking• Immunological factors
Prevention of Cervical Cancer
• Primary prevention:– Education to ↓ high risk sexual behaviour– Measures to avoid exposure to HPV & STIs
• Secondary prevention: – Detection & Treatment of precancerous lesions before they
progress to cervical cancer
Cervical Cancer Screening
• Papanicolou smear (cytology)• Visual Inspection techniques• Colposcopy, Cervicography• Molecular (HPV DNA) tests
Methods available
Limitations of Pap Smears for National Screening Programs
• Primary screening is repetitive, labour intensive, time consuming
• Subject to errors of interpretation • Sensitivity 60-70% • Complex logistics, advanced
training, good program implementation required
Limitations of Pap Smears for National Screening Programs
• Pap Smear as a screening methods may not be appropriate or adequate for many low-resource settings
• Even in large cities, quality Pap smears possible but require ongoing supervision, refresher training & continued supplies.
Cytology is not viable as a nationally accessible screening method in many developing countries
Visual Inspection Techniques* Unaided Visual Inspection* Visual inspection with acetic acid (VIA)* Visual inspection with acetic acid and
magnification (VIAM) * Visual inspection with Lugol’s Iodine (VILI)
Unaided Visual Inspection of Cervix
- Dx at stage III & IV ↓from 85% to 55%
- Dx at stage I & II: ↑ from 15% to 45%
Kerala Study 1977-87
Unaided Visual Inspection of Cervix
- 60% of Early disease could be identified - 11% were false positive- Only 15-20% of pre-cancerous lesions
could be detected
Singh V et al 1992
Good for Clinical Down stagingMisses Precancerous lesions
Visual inspection with acetic acid VIA
• Looking at the cervix to detect abnormalities after applying acetic acid
• Acetic acid is used to enhance and “mark” the aceto-white change of a pre-cancerous lesion or actual cancer
VIA- Basis
• Produced due to osmolar changes after acetic acid application, causing water of the cell to leave
• Collapse of the cell membrane around the abnormal and enlarged nucleus
• Altered lesion appears white due to reflection of the incidental light
VIA positive
Dysplastic lesion HPV lesion
VIA Negative
Normal Cervix
VIAM (Visual Inspection with Acetic Acid Using Magnification)
• VIAM is visualization of cervix after application of acetic acid using low power magnification (2.5x to 4x)
Magnascope (4X)
VILIPositive Negative
Normal squamous epithelium Columnar epithelium
Comparison of Screening Methods
Method Sensitivity (%) Specificity (%)
Cytology 45-85 80-98
VIA 60-90 66-96
HPV DNA 65-95 70-96
NEJM Nov17,2005
Screening Costs
Ca Cx prevention in Thailand: Single visit: VIA & Cryosurgery
• 5999 women tested by VIA-13.3% VIA + counseled for immediate Cryo- Accepted by 98.5%- Minor side effects: 2.2%, Major Cp: nil- 83.2% came for follow up, > 95% satisfied
RTCOG: Lancet 2003; 361: 814-820
Safe, acceptable, feasible
Visual Inspection Techniques in Low resource setting
• Noninvasive, easy to perform, inexpensive• All requirements are available locally• Can be performed by all levels of
healthcare workers, in almost any setting• Results are available immediately • Initial treatment can be provided at the
time of the examination
RCH program can act as a powerful tool in preventing Cervical cancer:
* Creating Awareness * Using Simple Screening methods
Conclusion
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