New guidelines on cervical cancer screening: what you need to know


Anna E. Mazzucco, Ph.D. and Diana Zuckerman, Ph.D.
2015

 

Should the HPV test be used in addition to or instead of a Pap smear to screen for cervical cancer?  This is a hotly debated issue, and here’s what you need to know.

The U.S. Preventive Services Task Force carefully studies research findings to determine the best way to screen for cancer and other diseases.  They recommend Pap smears every 3 years for women 21 and older.  They also advise that women who are 30 and older could instead have a Pap smear and HPV test every 5 years.  These tests are done at the same time when a woman goes to a doctor and has a sample taken from her cervix that is sent out for both types of tests.  We strongly support these guidelines.

However, 2 medical associations are issuing new guidelines in January 2015 that differ from the U.S Preventive Services guidelines: The Society of Gynecological Oncologists and the American Society of Colposcopists and Surgical Pathologists (ASCCP).[end Huh WK, et al, Use of primary high-risk human papillomavirus testing for cervical cancer screening: Interim clinical guidance, Gynecol Oncol (2015), http://dx.doi.org/10.1016/j.ygyno.2014.12.022] These groups represent the doctors who frequently diagnose and treat cervical cancer, although they are not the doctors most women see for a routine Pap smear or check-up, and they tend to be more focused on cancer treatment than on the best public health strategies for effective screening.

The guidelines support using the Cobas HPV test as an acceptable alternative to Pap smears for all women ages 25 and older.  This is different from other guidelines in 2 important ways:

  1. It recommends HPV testing for women 25-29, contrary to all other guidelines.
  2. It would replace Pap smears with HPV testing. Until now, the HPV test was approved only for use with a Pap smear.
  3. If a woman has a positive HPV test for HPV 16 or 18 (two different strains), the guidelines recommend colposcopy, a procedure that is more expensive and painful than a Pap smear.

In April 2014, the FDA approved the Cobas HPV test for these uses.  However, the FDA did not recommend that physicians or patients follow these guidelines.  The FDA points out that they are not making a judgment on the best way for women of any age to be screened for cervical cancer, they are merely approving the HPV test as an acceptable way to screen for cervical cancer.

Should you get the HPV test, Pap smears, or both?

Most women under 30 have been exposed to HPV.  If they rely on the HPV test for screening instead of the Pap smear, many will find that they have HPV but they will not know if the virus would go away by itself or ever cause problems.  For that reason, using the HPV test for women under 30 is very controversial.

Some doctors point out that the HPV test is more objective because it diagnoses HPV with a simple yes or no response, whereas the Pap smear is based on more subjective judgments about what cells look like.  However, being objectively correct about whether HPV is present does not accurately predict whether the HPV is dangerous and will cause cervical cancer.  On the contrary, the vast majority of women with HPV will never develop cervical cancer.  So, the objectivity of the test does not mean it is more accurate as a screening test.  In fact, research has been unable to prove whether using the HPV test alone is more or less accurate than the Pap smear alone for actually preventing cancer or saving lives.[end 2014 meeting materials of the Food and Drug Administration (FDA) microbiology devices panel. http://www.fda.gov/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/MicrobiologyDevicesPanel/ucm388531.htm; March 12, 2014. [Accessed July 2014]  It is certainly likely that the HPV test alone is less meaningful than the HPV test used with a Pap smear.

Concerns About replacing the Pap smear with the HPV test

If a woman gets an HPV test instead of a Pap smear, and the test shows she has a type of HPV that could cause cervical cancer, she will be worried.  She will need additional testing to know if the HPV is dangerous.  If she doesn’t have the money to follow up with either a Pap smear or a colposcopy, she will not have the information she needs to be sure to prevent cervical cancer.

The new guidelines encourage women who are found to have HPV 16 or HPV 18 (the strains most likely to cause cancer) to have colposcopies.  Colposcopies consist of examinations of the cervix which cost about $200-400 (or more depending on what procedures are done), and are more time-consuming and uncomfortable painful than a Pap smear.   In addition, not all OB/GYNs perform colposcopies, so the patient may need to find a specialist.

On the other hand, if a woman gets an HPV test and the results show she doesn’t have HPV, she’ll think she is fine.  But HPV is not the only cause of cancer of the cervix, and HPV tests can sometimes be wrong.  The woman may have abnormalities that would have been found using a Pap smear but that will not be diagnosed with the HPV test.

Unfortunately, these new guidelines support use of the HPV test as an alternative to the Pap smear in women as young as 25.  Even so, the guidelines admit that there is still a lot of missing information, and several other medical societies and public health organizations have not recommended replacement of the Pap smear.

Make a careful choice

We think women should continue to rely on Pap smears to screen for cervical cancer.  At the age of 30 or older, women may want to also be tested for HPV at the same time, especially if they have more than one sexual partner (or they have one sexual partner who recently had other sexual partners).

The bottom line:

There are no conclusive data on whether replacing the Pap smear with a HPV test is a good idea or not, particularly for women under 30.  We believe Pap smears are an important screening tool and that women should continue to rely on them every 3 years starting at age 21.

  • Pap smears are effective screening tools. Most U.S. women who get cervical cancer did not have Pap smears within the last 5 years. In fact, some never had Pap smears.
  • Pap smears identify abnormalities in the cervix, which is useful by itself or together with an HPV test. In contrast, the HPV test can only report if the woman currently has the HPV virus, not whether it will go away by itself (most will) and not whether it is causing abnormal cell growth that can cause cancer.
  • Pap smears usually only cost $20-40. HPV tests cost $80-100.