Cervical Cancer Prevention in Low-Resource AreasKey Words
Cervical cancer,
screening, prevention,
Pap test, human papillomavirus (
HPV). (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary 3.)
Summary
Innovative approaches to screening and treatment for cervical cancer can increase the number of women who obtain preventive treatment, according to clinical trials conducted in the United States and South Africa. These results may point the way to practical new approaches for reducing cervical cancer rates among women who are at elevated risk for the disease because of low medical resources.
Source
Journal of the American Medical Association, November 2, 2005.
(JAMA. 2005 Nov 2;294(17):2173-87)
Background
Cancer of the cervix (the neck or lower part of the womb) can be readily prevented when abnormal cells that could become cancerous are detected by a screening test and removed. Nevertheless worldwide, nearly half a million women are diagnosed with cervical cancer every year and about 233,000 women die of the disease. Eighty percent of these women live in less-developed countries, which often lack the health care facilities needed for conventional cervical cancer screening, diagnosis, and treatment.
In the developed world, early detection and treatment of cervical cancer is usually a process with several steps. The first step is a screening test (often a Pap test). If the screening test suggests the presence of an abnormality, the woman is asked to return to her doctor for further diagnostic testing. These additional tests distinguish between abnormalities that need prompt treatment from those that are unlikely to develop into cancer and can be safely monitored over time.
In the United States, most cases of cervical cancer are diagnosed in women who have never had a Pap test or who do not seek further diagnosis and treatment after getting an abnormal result on a Pap test.
Although the Pap test is widely available in the U.S., studies show that poverty, lack of health insurance, language difficulties, and cultural attitudes and beliefs about health care prevent many women from being screened.
In less-developed countries, the Pap test is an impractical approach to cervical cancer screening because of the scarcity of high-quality medical laboratories, which are needed to process both the screening test and the follow-up diagnostic tests. The need to make multiple doctor visits to get an abnormality diagnosed and treated may be a further hindrance..
The studies described here involved innovative approaches that were designed with hopes of overcoming some of these barriers.
This study involved 3,521 women - mostly Latinas - living in medically underserved areas of Orange County, California. The women were assigned at random to one of two groups. One group got “usual care” - they went home after having their Pap tests and got the test results in the mail two to four weeks later.
Women in this group whose test results were abnormal received follow-up phone calls advising them to see a doctor for further diagnostic testing. To find out how many of these women went back to their doctors within six months for follow-up testing and treatment, researchers interviewed them and also looked at their medical records.
Women in the second group were asked to wait in the clinic while their Pap tests were processed. The test results came back about an hour later. Women with high-grade precancerous abnormalities (the kind more likely to become cancer) were offered immediate treatment to remove the suspicious cells, rather than being referred for more diagnostic tests. Treated women were asked to return for two follow-up visits (at two weeks and then at three months) and to come back for another free Pap test in a year.
The lead author of this study is Wendy R. Brewster, M.D., Ph.D., of the University of California, Irvine, Medical Center in Orange, California
Results of Study 1
Among the women with severe abnormalities who were offered treatment during the same visit in which they had their Pap test, 88 percent completed preventive treatment within six months. By contrast, among women with the same abnormalities who were offered usual care, only 53 percent completed preventive treatment within six months.
The average length of the doctor visit for the women who got same-day treatment was just under three hours, compared with an hour and a quarter for the women who received usual care. Three-quarters of the women in the same-day group who responded to a questionnaire said they found the wait acceptable and 95 percent said they would choose to be in that group again.
Of the women in the usual-care group who responded to the questionnaire, two-thirds said they would have preferred to wait and get their test results during the same visit.
However, women who received same-day treatment were no more likely than those who received usual care to come back for another Pap test a year later. Overall, only 36 percent of women returned for the second test.
The second study involved 6,555 women living in a region in South Africa that lacked the medical resources needed for standard Pap test screening and follow-up diagnostic tests. As in the previously described study, researchers wanted to see if a low-resource “screen and treat” approach would prevent more cases of cervical cancer.
All of the women in this study received two screening tests - one to check for infection with the human papillomavirus (HPV), which can cause cervical cancer, and the other a simple visual check for signs of abnormalities on the cervix. The visual check used here is called VIA for “visual inspection with acetic acid.” VIA is a low-technology screening method that has been shown to be highly sensitive for detecting cervical abnormalities. A vinegar-based solution is applied to the cervix, which is then visually examined with a regular lighting source. The solution will turn precancerous cells white. VIA is less specific than the Pap test – that is, it more often wrongly suggests there is a problem when there isn’t.
Four hundred and fifty one women were removed from the study after this initial round of screening. Those with severe abnormalities that might be cancerous were referred immediately for follow-up diagnostic testing and treatment. Others were excluded if for some reason they were not good candidates for cryotherapy (a procedure that destroys cells on the cervix by freezing them).
The remaining women came back for a second visit a few days later and were randomly divided into three groups. In the first group, women whose HPV test results were positive were treated immediately with cryotherapy. In the second group, women whose visual check showed signs of abnormalities had the same procedure. Women in the third group got no treatment at that time, regardless of the results of their initial screening.
Women in all three groups were asked to come back for a follow-up colposcopy after six months. Colposcopy is a more high-tech way to visually inspect the cervix using a lighted magnifying instrument. Those with precancerous abnormalities received appropriate treatment.
The research team for this study was led by Lynette Denny, M.D., Ph.D., of the University of Cape Town in Cape Town, South Africa.
Results of Study 2
Women who received immediate treatment at the time of their initial screening were significantly less likely than those in the delayed-treatment group to have precancerous abnormalities detected after six months. Those who were treated right after a positive HPV test were 77 percent less likely to have developed abnormalities, while those who were treated right after a positive VIA check were 37 percent less likely.
Limitations
Not all cervical abnormalities lead to cancer. The “screen and treat” approaches investigated here skip the conventional diagnostic tests that, in developed countries like the United States, are usually done to confirm which abnormalities actually need treatment. This means that some women in these studies may have received unnecessary treatment.
Comments
“If the treatment were expensive or dangerous, [unnecessary treatment] could be a significant program limitation,” wrote Paul D. Blumenthal, M.D., M.P.H., of Johns Hopkins University in Baltimore, Maryland, and Lynne Gaffikin, Dr.P.H., of Evaluation and Research Technologies for Health, Inc., in Oakland, California, in an accompanying editorial.
But the treatments used in both studies are generally considered safe, they said, and the results obtained suggest that both approaches may effectively “prevent a common but preventable cancer, particularly among women in low-resource settings.”
Ted Trimble, M.D., of the National Cancer Institute’s Cancer Therapy Evaluation Program, agreed, saying, “The risk of overtreatment may be acceptable given the greater risk that patients may not return for necessary follow-up diagnosis and treatment.”
The findings of these two studies suggest promising new strategies for preventing cervical cancer in women who are at the highest risk for the disease and who are not being reached by existing prevention programs, he adds. |
