Cervical Cancer Screening Programs For Low-Resource Areas Appear Effective And Safe
Nov 2, 2005 - 3:20:38 AM
Two "screen and treat" cervical cancer prevention programs developed for high-risk women in low-resource settings resulted in a lower prevalence of precancerous cervical lesions and cervical cancer, according to a study in the November 2 issue of JAMA.
Each year 471,000 cases and 233,000 deaths occur from cervical cancer worldwide, of which 80 percent occur in less-developed countries that have access to less than 5 percent of global cancer treatment resources, according to background information in the article. The lifetime risk of a woman developing cervical cancer in a low-resource setting is approximately 2 percent to 4 percent. Cytology (cell) -based screening programs have markedly reduced the incidence of cervical cancer in developed countries that have the infrastructure to support these programs. However, these screening programs have been difficult to implement in low-resource settings.
Recently, a novel approach to cervical cancer prevention has been proposed that avoids the complex health infrastructure required by traditional approaches. This approach incorporates noncytology-based screening methods such as human papillomavirus (HPV) DNA testing or visual inspection with acetic acid (VIA; a weak acidic solution) followed by treatment of lesions using cryotherapy (medical treatment that involves application of nitrous oxide to lesions and a device using very low temperatures) of all eligible women with positive test results. Cryotherapy is a relatively low-technology treatment method. These approaches have advantages for low-resource settings because they are not cytology-based screening programs and do not require colposcopy (specialized equipment for examination of the vagina and the cervix), which overcome two of the greatest barriers to cervical cancer prevention. However, the efficacy of these screen-and-treat approaches has not been established, and there has been only limited safety data.
Lynette Denny, M.D., Ph.D., of the University of Cape Town, South Africa, and colleagues conducted a study to determine the safety and efficacy of two screen-and-treat approaches for cervical cancer prevention. The randomized clinical trial included 6,555 nonpregnant women, aged 35 to 65 years, and was conducted between June 2000 and December 2002 at ambulatory womens health clinics in Khayelitsha, South Africa. All patients were screened using human papillomavirus (HPV) DNA testing and visual inspection with VIA. Women were subsequently randomized to 1 of 3 groups: cryotherapy if she had a positive HPV DNA test result; cryotherapy if she had a positive VIA test result; or to delayed evaluation.
The researchers found that compared with the delayed evaluation group, the prevalence of biopsy-confirmed high-grade cervical intraepithelial neoplasia and cancer (CIN 2+) at 6 months was significantly less in both the HPV DNA and VIA groups. At 6 months, CIN grade 2+ was diagnosed in 0.80 percent of the women in the HPV DNA group and 2.23 percent in the VIA group compared with 3.55 percent in the delayed evaluation group. "Thus, the screen-and-treat approach using HPV DNA testing was associated with a 77 percent lower prevalence of CIN 2+ than in the delayed evaluation group at 6 months, whereas the screen-and-treat approach using VIA was associated with a 37 percent lower prevalence," the authors write.
Data were obtained from 2,708 women (74 percent of those scheduled to be examined) and the cumulative prevalence of CIN 2+ by 12 months in both screen-and-treat groups continued to be lower than in the delayed evaluation group. In the HPV DNA group, 1.42 percent had CIN 2+ by 12 months compared with 2.91 percent in the VIA group and 5.41 percent in the delayed evaluation group. "This translates into 1 case of CIN 2+ being averted for every 25 women enrolled in the HPV DNA group and 1 case being averted for every 40 women enrolled in the VIA group," the researchers write.
Although minor complaints, such as discharge and bleeding, were common after cryotherapy, major complications were rare.
"This trial has shown that screening and treating women based on the results of two alternative screening tests to cytology, HPV DNA testing and VIA, is safe and has a significant impact on the prevalence of CIN 2+ among women participating in such a program. In low-resource settings, screen-and-treat approaches may be able to reduce the risk of a common and easily preventable cancer in women," the authors conclude.
In an accompanying editorial, Paul D. Blumenthal, M.D., M.P.H., of Johns Hopkins University, Baltimore, and Lynne Gaffikin, Dr.P.H., of Evaluation and Research Technologies for Health Inc., Oakland, Calif., comment on the studies in this weeks JAMA on screening for cervical cancer.
"When faced with a challenge, identifying and seizing an opportunity can be the first step toward triumph. That is what public health approaches are often about. An important lesson from the work of Brewster et al and Denny et al is that whether in southern California or southern Africa, safe, acceptable, effective, and pragmatic public health approaches to cervical cancer prevention can be designed."
"The advent of a vaccine to prevent human papillomavirus infection, widely perceived to be just around the corner, is eagerly awaited to advance preventive capabilities. Recent data reported by Skjeldstad and colleagues made this development increasingly likely. However, even if a vaccine became available tomorrow, several generations of women worldwide would still need conventional care. To provide care to all women, future cervical cancer prevention programs worldwide will need to be designed to reach women who are at highest risk for disease and to ensure that the critical components of testing, treatment, and follow-up are realized as appropriate for every woman. Programs that build on the experience reported in these articles will have a good start in achieving those goals," they write.
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