(RxWiki News) About 12,000 women in the US are diagnosed with cervical cancer each year. While there is debate over screening approaches, tests that screen for cervical cancer can catch the disease early when it is easiest to treat.
Two main tests are used to find signs of cervical cancer: the Pap test (or Pap smear), which looks for precancerous cells, and the human papillomavirus (HPV) test, which detects the virus that is the cause of most cervical cancers. Current guidelines recommend that women have both tests, but the US Food and Drug Administration (FDA) recently approved cervical cancer screening using an HPV test alone.
Because cervical cancer occurs most often in women who have had no screening, doctors from Boston University School of Medicine are advocating that more women get cervical cancer testing of any kind.
"Get screened for cervical cancer."
Rebecca B. Perkins, MD, assistant professor of obstetrics and gynecology at Boston University, and Elizabeth A. Stier, MD, of the Department of Obstetrics and Gynecology at Boston Medical Center, co-wrote a commentary article calling for higher cervical cancer screening rates, regardless of which test is used.
Presently, the American Cancer Society, American Society of Colposcopy and Cervical Pathology, the American Congress of Obstetricians and Gynecologists and the US Preventive Services Task Force (USPSTF) recommend that women ages 30 to 65 get combined Pap and HPV tests every five years and Pap testing alone at three-year intervals. The Centers for Disease Control and Prevention (CDC) suggests that cervical cancer screening, at least with a Pap test, begin at age 21.
On April 24, 2014, the FDA approved the first HPV test for primary cervical cancer screening — the cobas HPV Test. According to the FDA, the cobas HPV Test could be used alone (without the Pap) for women aged 25 years or older. Professional medical organizations, however, have not yet issued any guidelines for this approach.
In their analysis, Drs. Perkins and Stier highlighted advantages of HPV testing. In one study cited, a single screening with HPV testing (whether it was cobas or another commercially available HPV test) found 95 percent of precancerous lesions, while Pap testing alone found only 40 to 70 percent of such lesions.
Screening tests need to be judged according to their sensitivity (able to detect most disease) and their likelihood of producing false-positive results, according to the authors of this commentary. For example, they said that primary HPV testing in females between the ages of 25 and 29 would have higher false-positive rates, while Pap tests have a comparatively lower sensitivity compared to HPV testing.
Ultimately, Drs. Perkins and Stier wrote, “Cotesting with Pap and HPV tests detects more disease than either test alone, but the improvement is modest. Cotesting with Pap and HPV detects approximately twice as many cases of cervical dysplasia [abnormal changes in cells] and cancer as Pap testing alone over a three- to five-year period but only 12 percent to 16 percent more cases than HPV testing alone.”
The authors stressed that at this point, many questions remain regarding the effectiveness of screening approaches — which test is most effective, or is combined testing the best approach? Until these questions are resolved, they have called for the screening of more women, regardless of the type of test, because most cervical cancer occurs in women who have not had any recent screening.
This commentary was published online June 10 in the Annals of Internal Medicine, and supported by a grant from the American Cancer Society.