April 28, 2014
News Review From Harvard Medical School -- FDA Says HPV Test Can Be Used before Pap
A test for human papilloma virus (HPV) can be used instead of a Pap smear as the first regular test a woman receives for cervical cancer. That's the decision announced April 24 by the U.S. Food and Drug Administration. HPV is the cause of nearly all cases of cervical cancer. The test, called cobas, is made by Roche Molecular Systems Inc. It was approved in 2011 to be used along with a Pap smear. Women age 30 or older can get Pap smears less often if an HPV test shows they are not infected. The Pap, an older test, involves removing cells from the cervix. They are examined under a microscope for signs of cervical cancer or abnormal cells that can become cancer. The new FDA decision means the HPV test can be used first for women age 26 or older. The test maker recommends a further test called colposcopy for women who test positive for HPV strains 16 or 18. These two cause most cases of cervical cancer. Women with other test results would get a Pap smear. HealthDay News wrote about the FDA decision.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Having regular Pap smears has dramatically decreased a woman's risk of developing cervical cancer. A Pap smear is a simple scraping of the surface of the cervix to get a sample of cells. The way these cells look under the microscope helps predict the chances that they will become cancerous.
Unlike the cause of most cancers, the most common cause of cervical cancer is well known. It's infection with human papillomavirus (HPV). Today we have excellent tests to detect this virus.
Testing for HPV, combined with a Pap smear, provides more information about cervical cancer risk. For women age 30 and over, it makes screening even more effective. Now the U.S. Food and Drug Administration (FDA) has expanded approval of HPV testing for cervical cancer. This test now can be done as the first test for women ages 25 and older.
The HPV test is not approved for use in younger women. That's because younger women with healthy immune systems are very likely to clear the infection. Testing for HPV under the age of 25 detects too many infections that will never be a problem.
The FDA approval of initial HPV testing as a cervical cancer screen was based on a study of more than 47,000 women ages 25 and older. The approved HPV test shows if HPV is present and identifies the specific HPV strain. That's important because HPV strains 16 and 18 cause most cervical cancers.
If a woman has either of these high-risk strains, the test maker suggests that she return for a colposcopy. In this procedure, the doctor uses a magnifying lens to closely examine the cervix. By looking through the colposcope, a doctor can identify abnormal-appearing areas of the cervix and take samples if necessary. The samples are examined under a microscope. This is called a biopsy. If precancerous cells are found, the cervix can be treated to prevent cancer.
If other strains of HPV are found, the woman has to come back for a Pap smear.
The advantage of screening first for HPV, rather than a Pap smear, is that the detection of the virus is much more sensitive. But most infections with HPV, especially in young women, go away without treatment.
The concern about screening first with an HPV test is that it will result in more women:
- Having colposcopy and treatment that they don't really need
- Having to return for a second office visit just to have a Pap smear
- Spending more money without clear health benefit
What Changes Can I Make Now?
The FDA approval of HPV testing as a first screening test does not change the most recent guidelines from the United States Preventive Services Task Force. The American College of Obstetricians and Gynecologists also has endorsed these guidelines.
Here are the recommendations for women at average risk of cervical cancer:
- Women younger than age 21 do not need routine screening.
- Women ages 21 to 29 should have a Pap smear once every 3 years.
- Women ages 30 to 65 should have a Pap smear every 3 years or a combination of a Pap smear and HPV testing every 5 years.
- Women ages 65 and older do not need routine screening if recent Pap smears have been normal.
These are guidelines. For personal reasons, you and your doctor may wish to choose HPV testing first or have more frequent Pap smears than recommended.
Think prevention. If you are a girl or woman age 26 or younger, the best way to prevent cervical cancer is to get vaccinated against HPV. Two vaccines, Cervarix and Gardasil, are available. Both of them target the major strains of HPV that cause cervical cancer. Gardasil also protects against genital warts and cancers of the anus, vagina and vulva.
Because it helps protect against genital warts, Gardasil is also recommended for boys and men in the same age range.
You can also help prevent cervical cancer by:
- Limiting your number of sexual partners to reduce possible exposure to HPV
- Using condoms
- Not smoking
What Can I Expect Looking to the Future?
The current cervical cancer screening guidelines will certainly be reexamined. If and when they will change is uncertain.