Screening for Cervical Cancer by Visual Inspection Techniques Dr Aruna Batra VMMC & SJH.
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Transcript of Screening for Cervical Cancer by Visual Inspection Techniques Dr Aruna Batra VMMC & 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
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
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)
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
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