Visual inspection with acetic acid (VIA): Evidence to date Original
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Visual inspection with acetic acid (VIA): Evidence to date Original source: Alliance for Cervical Cancer Prevention (ACCP) www.alliance-cxca.org
Overview: Description of VIA and how it works Infrastructure requirements What test results mean Test performance Strengths and limitations Program implications in low-resource settings
Types of visual inspection tests: Visual inspection with acetic acid (VIA) can be done with the naked eye (also called cervicoscopy or direct visual inspection [DVI]), or with low magnification (also called gynoscopy, aided VI, or VIAM). Visual inspection with Lugol’s iodine (VILI), also known as Schiller’s test, uses Lugol’s iodine instead of acetic acid.
What does VIA involve? Performing a vaginal speculum exam during which a health care provider applies dilute (3-5%) acetic acid (vinegar) to the cervix. Abnormal tissue temporarily appears white when exposed to vinegar. Viewing the cervix with the naked eye to identify color changes on the cervix. Determining whether the test result is positive or negative for possible precancerous lesions or cancer.
What infrastructure does VIA require? Private exam area Examination table Trained health professionals Adequate light source Sterile vaginal speculum New examination gloves, or HLD surgical gloves Large cotton swabs Dilute (3-5%) acetic acid (vinegar) and a small bowl Containers with 0.5% chlorine solution A plastic bucket with a plastic bag Quality assurance system to maximize accuracy
Categories for VIA test results: VIA Category Test-negative Test-positive Suspicious for cancer Clinical Findings No acetowhite lesions or faint acetowhite lesions; polyp, cervicitis, inflammation, Nabothian cysts. Sharp, distinct, well-defined, dense (opaque/dull or oyster white) acetowhite areas— with or without raised margins touching the squamocolumnar junction (SCJ); leukoplakia and warts. Clinically visible ulcerative, cauliflower-like growth or ulcer; oozing and/or bleeding on touch.
Categories for VIA tests results: Acetowhite area far from squamocolumnar junction (SCJ) and not touching it is insignificant. Acetowhite area adjacent to SCJ is significant. Negative Photo source: JHPIEGO Positive
Categories for VIA tests results: Suspicious for cancer Photo source: PAHO, Jose Jeronimo
Management options: What to do if the VIA test is positive? Offer to treat immediately. Refer for confirmatory diagnosis or adjunctive test.
Test performance: Sensitivity and specificity Sensitivity: The proportion of all those with disease that the test correctly identifies as positive. Specificity: The proportion of all those without disease (normal) that the test correctly identifies as negative.
VIA test performance (n 7): Sensitivity Specificity Minimum 65% 64% Maximum 96% 98% Median* 84% 82% Mean* 81% 83% * Weighted median and mean based on study sample size Source: Adapted from Gaffikin, 2003
Strengths of VIA: Simple, easy-to-learn approach that is minimally reliant upon infrastructure. Low start-up and sustaining costs. Many types of health care providers can perform the procedure. Test results are available immediately. Requires only one visit. May be possible to integrate VIA screening into primary health care services.
Limitations of VIA: Moderate specificity results in resources being spent on unnecessary treatment of women who are free of precancerous lesions in a single-visit approach. No conclusive evidence regarding the health or cost implications of over-treatment, particularly in areas with high HIV prevalence. There is a need for developing standard training methods and quality assurance measures. Likely to be less accurate among post-menopausal women. Rater dependent.
Conclusions: VIA is a promising new approach. Ongoing VIA-based projects by ACCP partners in a number of countries are investigating long-term effectiveness of the VIA test-and-treat approach. Several questions remain, including: Which factors maximize VIA’s performance? How can quality of VIA services outside of a controlled setting be ensured? How can VIA best be incorporated into prevention programs? What is the long-term impact on cancer mortality from programs incorporating VIA?
References: ACCP. Visual screening approaches: Promising alternative screening strategies. Cervical Cancer Prevention Fact Sheet. (October 2002). ACCP & World Health Organization. Cervical cancer prevention in developing countries: A review of screening and programmatic strategies. (Forthcoming, November 2003). Gaffikin L, Lauterbach M, Blumenthal PD. “Performance of visual inspection with acetic acid for cervical cancer screening: A qualitative summary of evidence to date,” Obstetrical and Gynaecological Review 58(8):543-550. (August 2003). McIntosh N, Blumenthal PD, Blouse A, eds. Cervical cancer prevention guidelines for low-resource settings. Baltimore, MD:JHPEIGO. (2001). Riegelman RK and Hirsch RP. Studying a study and testing a test: How to read the medical Literature (2nd Edition). Boston, MA:Little, Brown and Company. (1989).
For more information on cervical cancer prevention: The Alliance for Cervical Cancer Prevention (ACCP) www.alliance-cxca.org ACCP partner organizations: EngenderHealth www.engenderhealth.org International Agency for Research on Cancer (IARC) www.iarc.fr JHPIEGO www.jhpiego.org Pan American Health Organization (PAHO) www.paho.org Program for Appropriate Technology in Health (PATH) www.path.org