New Test for Cervical Cancer Allows Women to Gather Tissue Samples Themselves
Jan. 4, 2000 (New York) -- Two new studies appearing in the Jan. 5 issue of TheJournal of the American Medical Association conclude that human papilloma virus (HPV) DNA testing is as effective as a Pap smear for identifying women with a high likelihood of developing cervical cancer and should be used with Pap smears in most women for routine cervical cancer screening. At a press conference on Tuesday, study authors said that the addition of the new test to conventional screening methods offers many possibilities for improving cervical cancer detection rates, including giving women the option of collecting their own vaginal samples in a doctor's office.
Cervical cancer is the second leading cause of cancer-related deaths in women worldwide. According to the American Cancer Society and others, 50-60% of women who develop invasive cervical cancer have not had their recommended annual Pap smear in the previous three years despite contact with a health care provider during that time. Possible reasons include inconvenience, time, and discomfort; physicians assuming that the Pap smear is being obtained elsewhere; and some male physicians feeling uncomfortable obtaining Pap smears and taking sexual histories.
When Pap smears are performed, cancer may be missed in up to 40% of cases. But a large body of evidence suggests that HPV is present in virtually all of the most life-threatening cases of cervical cancer, suggesting that testing for HPV could help catch more cancers early on.
"We've known now for over a decade that cervical cancer is caused by a specific type of human papilloma virus, or HPV," says Thomas C. Wright Jr., MD. His study found that having women collect their own vaginal specimens with a special kit for HPV testing was as effective in detecting the virus as standard Pap smears, in which the physician obtained the samples. Wright, of the College of Physicians and Surgeons of Columbia University, says the study shows that the new test has the potential to save lives, particularly in areas or populations where women have limited access to medical services.
Wright and colleagues examined 1,415 previously unscreened women aged 35-65 from a township outside Cape Town, South Africa. Women self-performed a vaginal swab with the special collection kit at a clinic and, after returning it, were then screened using a conventional Pap test, visual inspection of the cervix, and HPV testing of a physician-obtained vaginal sample.
The physician-performed HPV DNA test was positive in 84% of women with precancers and cancers, whereas the conventional Pap smear was positive in 68%. In the patient-collected samples, HPV was positive in 66%. The false-positive rates -- the percentage of cases diagnosed incorrectly as cancer or precancer -- were 17% for HPV testing of self-collected samples and 12% for Pap smears.