Cervical Cancer Screening in Low Resource Settings: Using Visual Inspection With Acetic Acid

Katherine Camacho Carr, CNM, PhD; John W. Sellors, MD

Disclosures

J Midwifery Womens Health. 2004;49(4) 

In This Article

Screening in Low Resource Settings

Several important pieces of information need to be considered before planning a screening program in a low resource setting. For the near future, cytology-based screening programs and/or DNA typing of HPV are beyond the capacity of many health services in developing countries, although this may change as rapid, accurate, and inexpensive HPV screening diagnostics become available.[2,3,17,18] Papanicolaou smear screening requires health care providers who have been well trained to obtain adequate smears, access to equipment and supplies, linkages to a cytology laboratory with trained cytologists and cytotechnicians, mechanisms for ensuring quality of samples and accuracy of interpretations, an ability to follow-up women who need treatment, linkages, and transportation to the next level of care for further diagnosis and/or treatment. Many of these elements may be lacking in low resource settings, making it impossible to offer effective Papanicolaou screening.

Even under ideal circumstances, Papanicolaou screening is at best an only moderately effective screening technique if it is done only once in a lifetime or infrequently. Metanalysis and a systematic review of the literature has found the Papanicolaou smear to have an overall sensitivity of 51% and a specificity of 98% for detection of any grade of CIN.[19,20,21] This means that in the best cytology program, there are many false-negative results, because only half of the women with CIN are correctly diagnosed as having CIN.[9] The sensitivity may be even lower when screening women who are postmenopausal due to the changes in the cervix and the difficulty of obtaining an adequate sample from the transformation zone. In well-established Papanicolaou screening programs, repeated periodic testing is relied on to eventually detect CIN. New technologies, such as liquid-based cytology, have been developed to improve cytologic screening accuracy. Fey and Beal provide a review of these technologies.[22]

Other screening techniques that are less resource intensive and that improve screening accuracy in low-resource settings must be considered. In addition, country-specific information is helpful in identifying when to initiate screening, how often to screen, and when to recommend treatment and/or follow-up.[9] Screening should focus on the women at highest risk for precursor lesions. Because cervical cancer develops slowly, screening can be relatively infrequent and still have a notable impact on a population.[2,3,4,9] Although strategies may vary on the basis of country and local epidemiologic data, some programs in limited resource settings are assessing screening and treatment at a single visit because this eliminates losses to follow-up after screening.[23]

Given the challenges of implementing Papanicolaou screening or other new technologies in low resource settings, simple visual approaches to screening have been studied extensively to identify precursor lesions and to determine the accuracy and acceptability of screening to women.[2,3,9,24,25,26,27,28,29,30] Visual screening relies on visual inspection of the cervix with the naked eye to observe for pathologic changes. Initially, this approach that used visual inspection alone, which was called unaided visual inspection, was not very accurate in identifying precursor lesions.[30,31] However, visual inspection with acetic acid (VIA) has consistently shown promise as a simple, accurate, and cost-effective screening technique to identify epithelial abnormalities including precursor lesions of the cervix.[28,29,30,31,32,33,34,35,36,37]

Several studies that included the reference standard of colposcopy and biopsy in addition to VIA to verify the diagnosis examined the accuracy of VIA. They found the sensitivity of VIA in detecting high-grade lesions to be at least equal to cytology, whereas the specificity is somewhat lower.[26,32] Two methodologically rigorous studies, with a total of nearly 4,000 women screened, showed that the specificity and sensitivity of VIA for biopsy-proven high-grade lesions are approximately 74% and 69%, respectively.[29,37] A recent study by Sankaranarayanan et al. on 4,444 women in India, which also verified findings with colposcopy and biopsy, reported an 88% sensitivity for VIA and a specificity of 78%.[38]

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