DEAR DOCTOR K:
I am 31 years old and have always had normal Pap smears. I just read that HPV testing might be better. What do you suggest?
Screening for cervical cancer has led to a dramatic decrease in the disease. Until fairly recently, all cervical cancer screening was done by Pap smear. But the FDA recently approved the use of a new screening tool — the HPV DNA test — that may eventually take its place.
Most cases of cervical cancer or precancerous cervical changes are caused by the human papilloma virus (HPV). There are more than 100 different types of HPV; some (but not all) types of HPV can cause cervical cancer.
When HPV causes an infection of the cells of the cervix, it changes the shape of those cells. That abnormal shape is what shows up in a Pap smear. The Pap test can’t see HPV; it just shows the cell changes caused by HPV. Those changes were recognized many decades before anyone knew that cervical cancer was caused by a virus, and that the virus was HPV.
Until recently, HPV DNA tests were only used together with Pap tests. If a woman’s Pap test found abnormal cervical cells, HPV DNA tests could identify whether the woman carried the types of HPV more likely to cause cervical cancer.
The problem with that strategy is that the Pap test is not perfect. There are women who have an HPV infection that is causing cervical cancer (or a precancerous condition) but who have a “normal” Pap test. If the Pap is falsely negative, the HPV test wouldn’t be ordered. So the woman would lose out on a second chance to diagnose the cancer.
The FDA has now approved the HPV test for screening in place of Pap smears in women age 25 and older. The advantage is that the HPV DNA test is much more sensitive than the Pap test in detecting early cases of cervical cancer caused by HPV.
But there’s a problem with HPV testing, as well. Most HPV infections — especially in young women — go away without treatment and do not lead to cancer. So many HPV tests will be abnormal in women who don’t have cancer. But the abnormal test will generate fear — and additional (unnecessary) testing.
In general, I follow the guidelines on cancer screening issued by the U.S. Preventive Services Task Force. This is an independent panel of experts in primary care and prevention funded by the federal government. Currently, the panel recommends:
- Ages younger than 21: Cervical cancer screening is not recommended.
- Ages 21 to 29: Pap smears every three years.
- Ages 30 to 65: Pap smears every three years, or screening by a combination of Pap smear and HPV testing every five years.
- Ages 65 and over: Screening is not recommended if recent Pap tests are normal.
You and your doctor should discuss which test is best for you. Consider your personal preferences, each test’s risks and benefits, your medical history and your individual risk of cervical cancer.