Going Beyond the PAP: Who should get screened and when
Most women are aware of the Pap Test or "Pap Smear," which is used to detect changes in the cells of the cervix and can detect the presence of cervical cancer. This relatively simple test allows for early detection of cell changes, which makes treatment possible and, often, very successful. The success of early detection has made the Pap Test an integral tool in the reduction of cervical cancer deaths in the United States. Cervical cancer rates have fallen more than 50% in the past 30 years in the US due to widespread use of the Pap Test. However, cervical cancer still remains a common gynecologic cancer around the world: each year, about half a million women are diagnosed with the cancer and close to 250,000 die from it. While the Pap Test has been the first line of defense, there are now new screenings and vaccines that take the "Pap" further.
HPV: Cervical Cancer Culprit:
Cervical cancer as well as genital warts are known to be caused by the human papilloma virus (HPV), one of the most common sexually transmitted infections. Today as many as 80 percent of women will be exposed to it at some point in their lives. HPV typically has no symptoms, and more often than not, particularly in younger women, the virus goes away on its own, causing no damage to the woman. (Most people are unaware they even have HPV.) While there are more than 100 strains of HPV, strains HPV 16 and 18 are the cause of most cervical cancers and strains 6 and 8 are the cause of genital warts. If cervical disease is caught early on, it is easily treated; however, if it progresses to an advanced stage, it is painful, much more difficult to treat and can be fatal
Cervical Cancer Testing:
For many years standard Pap Test was done during women's annual gynecological exam to screen for cellular changes. If the Pap came back with abnormal results, women would undergo a colposcopy, whereby the gynecologist looked at the cervix directly through a microscope (colposcope) and took biopsies of any abnormalities. The biopsies were then analyzed to rule out precancerous changes.
Today, however, with better quality Paps, the adjunct of HPV testing and new Pap Smear guidelines many women have been spared from undergoing unnecessary testing and painful biopsies.
The introduction of the liquid Pap has significantly improved the quality of Pap Smears making the interpretation of them considerably more accurate. With the liquid Pap Test, a cytobrush is used to obtain a sampling of microscopic cells from the woman's cervix. The brush is then placed into a vial that contains a liquid medium and swished around to dislodge the cells into the fluid. The vial is sent to the lab and spun in a process that separates the cervical cells, and filters them out. The cells are then placed under a microscope and evaluated. The remaining fluid can then be used for further analysis of HPV DNA testing.
Since most women under 30 often "clear" the HPV virus with no intervention, the HPV DNA testing is not routinely done with the Pap Test annually in this age group. However, routine HPV DNA testing in combination with the Pap is now FDA approved and recommended by the American College of Obstetricians & Gynecologists (ACOG), as well as the American Cancer Society and other professional groups, for women 30 and over.
New Testing Guidelines:
In November 2009 ACOG revised cervical cancer screening guidelines. These new recommendations reflect the fact that the immune system clears the HPV in 1 to 2 years for most adolescents as well as some of the cervical changes it can make in this age group.
The guidelines include:
- Cervical Cancer screening should begin at age 21 years.
- Women from ages 21 to 30 should be screened every two years instead of annually.
- Women age 30 and older who are low risk and have had three consecutive negative cervical cytology test results may be screened once every three years.
- Co-testing, using the combination of cytology plus HPV DNA testing is an appropriate screening test for women older than 30 years. Any low risk women aged 30 years or older who receive negative test results on both cervical cytology screening and HPV DNA testing should be rescreened no sooner than 3 years subsequently.
- Women who have had a total hysterectomy for benign indications and have no prior history of high grade CIN can discontinue routine Pap testing.
- Women with certain risk factors may need more frequent screening, including those who have HIV, are immune suppressed, were exposed to DES in utero, have been treated for cervical neoplasia or cervical cancer.
HPV Vaccination:
Two vaccines that protect against the high-risk strains of HPV are available today. They are most effective when given before the onset of sexual activity (and thus potential exposure to HPV). They areespecially indicated for young girls ages 9-13, however, they can be given up to age 26. These vaccines trick the immune system so that if the real virus is contracted, it renders it neutralized. These vaccines do not protect against all strains of HPV (primarily 16 and 18),and are well tolerated. One of the two vaccines also protects against HPV strains 6 and 8 which are known to cause genital warts. A complete vaccination series includes 3 shots over a 6 month period.
All young women should discuss HPV vaccination with their pediatricians and/or gynecologists. Furthermore, your gynecologist will advise you as to the appropriate Pap screening interval that applies to you based on your age and risk factors. It is very important to continue to have an annual gynecological exam, be open and honest with your healthcare provider and not hesitate to ask questions. An informed patient is a good patient.