Dr. Langdon is an obstetrician gynecologist with 19 years of clinical experience in a suburban Midwestern community. She is the inventor of a patent pending medical device to treat a common gynecologic condition and she's researched and written extensively about women's health.
Let's face it, going to a gynecologist isn’t all that fun. I dread it, and I’m a semi-retired gynecologist. But it’s an important life-long habit. One of the most important reasons to have a gynecologic exam over the age of 21 is to start a regimen of pap smears.
What does a pap smear do, you ask? It helps detect the beginnings of cervical cancer. More specifically, it detects abnormalities in the cells of the cervix which are usually due to the Human Papilloma Virus (HPV). This is the virus that can result in genital warts known as condyloma. The most common genital subtypes of HPV are 6,11,16, and 18. While 6 and 11 can result in genital warts,16 and 18 are associated with cervical cancer. 100% of all cervical cancers are due to one or more types of HPV.
The pap smear is the first screening test for cancer ever invented by modern medicine. Over the last 30 years, the rate of cervical cancer deaths has dropped by more than 50%–in large part, due to the pap smear.
The history of the pap smear
The pap smear dates back to 1928 when Dr. Papanicolaou suggested that cells scraped from the cervix and smeared onto a glass slide could be evaluated under a microscope to look for cancer cells.
Today, pap smears are collected in a liquid medium and evaluated for precancerous cells, cancer cells, and the presence of HPV and other STIs. Cervical cancer grows slowly and many precancerous conditions resolve themselves on their own. In fact, infections with HPV disappear within a few years in most teenagers and young adults under the age of 30. This is why the American College of Obstetrics and Gynecology (ACOG) changed their recommendations so that unnecessary testing, treatments, and expenses are avoided.
Pap smear recommendations
The best time to get a pap smear is after the menstrual period is over and the clinical recommendation is to get a pap smear every 3 years. This is drastically different from the recommendation when I first started practice in 1995. The guidance then was a yearly pap screening until three normal test results were obtained. A pap smear is not recommended for women under the age of 21 regardless of what age they first had sex. However, STI (gonorrhea, chlamydia, herpes) testing should be done based on risk factors and symptoms. For women aged 21-29, a cadence of pap smears without HPV testing every three years is sufficient. Many young women may have received the HPV vaccines as teenagers (which would lower their risk of an HPV related problem) and those who did not receive the HPV vaccine have a high rate of clearing the infection anyway. The table below shows the types of HPV vaccines available.
After age 30 and until age 65, a pap smear with HPV testing should be done every five years (or pap smears alone every three years). After 65, if two previous tests (paps and HPV) are negative then no more screenings are needed. Likewise, if pap smears alone are negative for 3 consecutive tests, then testing can stop at that point. This recommendation differs for women with certain health conditions. Women with a history of dysplasia (CIN 1, 2, or 3) must continue testing beyond age 65. Dysplasia (also known as cervico-intraepithelial neoplasia, a mouthful, I know!) is not cancer. It is what’s known as a “high-grade” lesion. CIN 1 is considered low-grade or mild dysplasia and CIN 2 and 3 are moderate and severe dysplasia. Screening recommendations and follow-up testing are also different for women who have smoking and other immunodeficiency states such as HIV, DES exposure in the womb, and a history of previous cervical cancer.
Abnormal results and treatment
So what happens if a pap smear comes back with an abnormal result such as dysplasia? It depends of whether it is mild, moderate, or severe. Since mild dysplasia usually clears up on its own, follow-up pap smears are sufficient. Even though moderate and severe dysplasia are not cancer, they require a follow-up procedure called a colposcopy. This is like an extended pelvic exam where the gynecologist applies a dilute acid and lugol's (an iodine solution) that visually highlights abnormal cells under a mobile microscope (called a colposcope). Once an area is identified as abnormal, a small biopsy is taken which can cause a slight pinch. This tissue is sent to the lab. In the case that the moderate or severe dysplasia is confirmed by colposcopy, then a procedure known as LEEP is performed. It’s a surgical removal of a small section of the diseased cervix. Very rarely, a more extensive procedure known as a cone biopsy is performed. The only reason to do this is if there is evidence that abnormal tissue persists or if cancer is found on the colposcopy.
Pap smears have saved countless lives and are responsible for reducing the number of women from losing their fertility prematurely due to treatment for cervical cancer. Until prevention of HPV is widely embraced with vaccines, pap smears will be necessary. Hopefully, there will come a time when home-based 'pap' or collection of cervical cells becomes the norm so that women have more control over their reproductive health. Exciting studies are underway to determine how this might be done!
- Berkowitz Z, Saraiya M, Sawaya GF. Cervical Cancer Screening Intervals, 2006 to 2009: Moving Beyond Annual Testing. JAMA Intern Med. 2013;173(10):922–924. doi:10.1001/jamainternmed.2013.368
- American Congress of Obstetricians and Gynecologists. ACOG practice bulletin no. 131: screening for cervical cancer. Obstet Gynecol 2012;120:1222–38. May 22, 2013.
- Vesco KK, Whitlock EP, Eder M, Burda BU, Senger CA, Lutz K. Risk factors and other epidemiologic considerations for cervical cancer screening: a narrative review for the U.S. Preventive Services Task Force. Ann Intern Med. 2011;155:698-705. Accessed May 22, 2013.
- American Cancer Society. What are the key statistics about cervical cancer? 2013.
- Cervarix Summary of Product Characteristics. emc.medicines.org.uk/medicine/20204/SPC/Cervarix. December 23, 2009.