Using data from Thai statistics on prevalence and costs of cervical cancer, as well as careful estimates of the quality of assorted screening tests, researchers developed a computer model to mimic the natural history of cervical conditions that lead to cancer.
They used the model to compare the costs and benefits of three screening techniques for cervical cancer: visual inspection; DNA testing for human papilloma virus (HPV), a known precursor of cervical cancer; or traditional Pap smears. In visual inspection, a health professional wipes a patient's cervix with acetic acid (vinegar), then looks for tissue abnormalities. Tissue harboring precancerous lesions turns white when exposed to vinegar.
Comparing each strategy with the next least expensive alternative, researchers found that visual inspection every five years in women ages 35 to 55, with immediate treatment where indicated being accepted by most women with eligible lesions, was the most cost-effective option at $517 per year of life saved. Only if HPV testing could be provided for $5 and 90 percent of patients agreed to follow-up care could HPV screening provide similar results, at a cost of $679 per life year saved. Pap smears would be as efficient only if at least 90 percent of the women received follow-up care and the tests were at least 80 percent sensitive in accurately detecting precancerous lesions.
Compared to no screening, the scientists estimate that visual inspection could achieve an 83 percent reduction in cervical cancer deaths at a cost of only $524 per year of life saved.
"Such a screening program would have a huge impact on women's health while increasing the overall national per capita health expenditure for Thailand, currently at $112, by less than 1 percent," says Paul D. Blumenthal, M.D., associate professor of gynecology and obstetrics at Hopkins and an author of the study. "After setting up a screening infrastructure, the annual cost of a visual inspection screening program with immediate treatment for the entire Thailand female population would only cost 79 cents per woman, or $4.7 million annually."
Thailand was chosen for study because it has relatively high rates of cervical cancer death, a largely rural population, low national HIV prevalence and minimal lab resources of the kind needed for Pap smears. The country has identified cervical cancer as a key public health problem and is implementing a pilot program with visual inspection as an alternative screening strategy.
To interview Blumenthal, please contact Karen Blum at 410-955-1534 or kblum@jhmi.edu.
Journal
JNCI Journal of the National Cancer Institute