For decades, Pap smears have been a critical health tool for people with uteruses.
Pap smears, also known as Pap tests, are used to identify cancerous and precancerous cells in the cervix, allowing doctors to detect cervical cancer in its early stages or before it has even developed.
Over the years, updates to Pap testing guidelines and a growing body of research on the human papillomavirus (HPV) — the leading cause of cervical cancer — have led to further strides in cervical cancer prevention.
Before you book your next gynecologist appointment, it’s important to know the differences been Pap and HPV testing, and to get acquainted with the latest guidelines for cervical cancer screening. These recommendations, which change as women age, were updated in 2018 to reflect new testing options for women over 30.
We spoke with experts to find out what women need to know about cervical cancer screening and prevention today.
The purpose of the Pap
The primary purpose of a Pap smear is to detect suspicious cells in the cervix that could indicate a risk of cancer. Terms like precancer, dysplasia and neoplasia are used interchangeably to refer to cells that are abnormal but are not cancer, according to the National Cancer Institute.
For some women, a cervical cancer screening also includes HPV testing in addition to or in lieu of a Pap smear. With the help of Pap and HPV testing, cervical cancer is one of the most preventable cancers.
“A Pap can sometimes help us find other conditions, like infections,” says Dr. Ana Cepin, assistant professor of obstetrics and gynecology at Columbia University Medical Center and medical director of New York-Presbyterian’s Family Planning Clinic. “But that’s certainly not a primary reason why a woman should have a Pap smear done.”
The link between HPV and cervical cancer
Nearly every case of cervical cancer is caused by HPV, but not all types of HPV lead to cancer. The vast majority of cervical cancer cases are connected to only two strands of the virus.
HPV is also the most common sexually transmitted infection. “Almost everyone will have a transient HPV infection at some point in their lifetime,” says Dr. Lisa Barroilhet, associate professor of gynecologic oncology at the University of Wisconsin. A transient infection is one that clears up on its own, usually within 12 months.
Aside from cervical cancer, HPV can also cause other cancers, including anal cancer, throat cancer and penile cancer. There are currently three FDA-approved vaccines that protect against HPV infection. Every year in the U.S., HPV causes 33,700 cancers in men and women, but HPV vaccination can prevent more than 31,000 of the cancers from ever developing, according to the CDC. The CDC recommends that both boys and girls get the HPV vaccine during adolescence, ideally before sexual activity begins. Until recently, HPV vaccination was only approved for people 26 and younger, but the FDA expanded approval to men and women ages 27 to 45.
Although the HPV vaccine guards against some strains of the virus, it doesn’t protect against all of them. That means that even if you’ve been vaccinated, it’s important to go in for regular cervical cancer screenings.
What to expect in the exam room
Whether you’re going in for a Pap smear, an HPV test or both, you can expect the same procedure at your doctor’s office.
The process can be a little uncomfortable, but it’s quick and generally well-tolerated by patients, Cepin says. You’ll lie on the exam table with your feet propped up in stirrups as your doctor inserts a speculum into your vagina, then uses a brush or spatula to collect cells from the cervix. You may feel some pressure from the speculum, but the procedure is usually over within a minute. After that, your doctor will send the cell sample to the lab for evaluation.
What happens next at the lab depends on which test you’re having done.
For a Pap smear, cervical cells are smeared on a slide and examined under a microscope. A pathologist then subjectively categorizes any abnormalities in the cells. An HPV test, on the other hand, is a nonsubjective test to check for certain high-risk types of HPV, Barroilhet says. She explains that Pap smear analysis is a less precise science than HPV testing. “There’s a subjective component to it that’s going to make it a little less accurate,” Barroilhet says. That’s why false-positive results occur occasionally in Pap smears, but they’re extremely rare in HPV tests.
To ensure accurate results, the American College of Obstetricians and Gynecologists says to avoid douching, intercourse and any vaginal medications for two days before your screening. You should also avoid scheduling your exam during your period. If your screening lands when your flow is heavy, see if you can reschedule. But if you’re only lightly spotting, it’s OK to keep your appointment, Cepin says.
Guidelines for Pap and HPV testing
Pap smears used to be a yearly milestone for most adult women. But in 2012, the U.S. Preventive Services Task Force released new guidelines indicating that women ages 21 to 65 only need a Pap smear every three years, and that women ages 30 to 65 can choose to wait even longer — every five years — if they receive both Pap and HPV testing. In August 2018, the guidelines were updated again to reflect a third choice for women 30 and over: HPV testing alone, every five years.
Pap smear use in the U.S. is still only “slowly aligning with 2012 guidelines,” according a 2017 study. The idea of longer intervals between tests left some women feeling uneasy; shouldn’t frequent testing lead to earlier detection of cancer? But too much testing can cause more harm than good, resulting in unnecessary follow-up appointments and invasive procedures to treat infections that would otherwise clear up on their own. “We don’t want to know about transient changes that are going to go away on their own for the most part,” Cepin says. “It’s safe to wait that period of time between tests.”
The benefit of HPV testing alone for the 30-to-65 group is that it can help avoid false-positive results and unnecessary follow-up appointments, explains Dr. Diane M. Harper, a professor of family medicine at the University of Michigan.
“When we use just the HPV test, we are much more likely to target the women who are truly at risk and are truly abnormal,” she says. Co-testing with both Pap and HPV testing is more likely to yield a false positive, which occurs when cervical cells collected during a Pap smear are identified as “abnormal” but are ultimately found not to be cancerous or precancerous.
In that case, women “still have to go through the colposcopy and biopsy to find out they’re normal and don’t have anything,” Harper says. “That is the harm in doing the co-testing.”
For women under 30, the CDC and the U.S. Preventive Services Task Force do not recommend routine HPV testing, since HPV is so prevalent among women in their 20s and most cases clear up on their own.
There are a few exceptions to the testing recommendations. Some women, including those with weakened immune systems, may need more frequent testing. Women who have had a hysterectomy with cervix removal may not need any screening at all.
If you’re not sure which guidelines apply to you, talk to your doctor to determine the screening interval and tests that best fit your needs.
My Pap smear came back abnormal, or I tested positive for HPV — now what?
Don’t panic. A one-off abnormal Pap smear or positive HPV doesn’t mean you have or will ever develop cancer.
“Almost everyone has an abnormal Pap over the course of their lifetime,” Barroilhet says. “But it’s persistent abnormalities or persistent HPV positivity that are going to indicate risk of dysplasia, and that’s when additional evaluation needs to happen.”
If you’re between 30 and 65 and have received abnormal Pap or HPV test results, your doctor may order a colposcopy, which is a procedure to visually examine the cervix with a bright light and magnifying lens. For women under 30 who receive an abnormal Pap smear result, your doctor will determine the best course of action, whether that means a repeat Pap smear or an HPV test. If you then receive an HPV test that comes back positive, your doctor may order a colposcopy.
Undergoing a colposcopy is a lot like getting a Pap smear, Harper says, except that the speculum stays in the vagina longer. If your doctor sees any abnormalities, she’ll take a biopsy from the cervix, which Harper says feels like a quick pinch. After a biopsy, it’s normal to experience some cramping, spotting or dark discharge for a few days.
Interpreting biopsy results
Biopsy results are categorized by level of severity, and different categorizations come with different follow-up and treatment protocols.
You may hear your doctor refer to cervical intraepithelial neoplasia, or CIN, or cervical dysplasia; both terms are used to talk about abnormal precancerous cells. Cervical biopsies are classified by their CIN.
- CIN 1 means that changes to the cells in the cervix are mild and should resolve on their own without treatment. After a CIN 1 classification, women are typically monitored with a repeat Pap or HPV test within a year.
- A CIN 2 or CIN 3 categorization refers to moderate or high-grade changes to cells. This classification may warrant a procedure to remove or destroy part of the cervix. In this case, the patient’s age and fertility plans are important factors.
An excisional procedure performed either with a small electrical wire loop (called LEEP) or a laser knife (called cold knife conization) is often recommended to treat precancerous cells, but this type of treatment can cause problems for women who plan to have children. If family planning is on your radar, your doctor may suggest an ablative procedure like cryotherapy, or freezing the cervix, to destroy abnormal cells without removing part of the cervix.
“In general, we don’t like cryotherapy as much as excisional procedures,” Barroilhet says. “When you remove the tissue during an excisional procedure, you get another opportunity to have a pathologist look at it and say there’s definitely no cancer. But an ablative therapy can be safer if a pregnancy is planned. It’s about working with the patient, going over the pros and cons of both approaches and tailoring it to meet their needs.”
Guidelines for managing abnormal cervical cancer screening results are determined by the ASCCP, the Society for Lower Genital Tract Disorders, which lays out recommended treatment steps in a downloadable app.
Common misconceptions about cervical cancer screenings
In 2016, about 75 percent of women in the United States between 18 and 64 years old reported having had a Pap smear in the past three years, according to data from the Kaiser Family Foundation. But that self-reported data doesn’t quite line up with reality, Harper says.
“When you go back and look at health records, the rate is more like 60 percent,” she says. “There’s a mismatch of what women think is happening and what is happening.”
One reason for the confusion is that some women mistake all types of speculum exams for Pap tests or cancer screenings.
“People don’t necessarily know that all speculum exams don’t necessarily mean a Pap smear,” Cepin says. “The two are not synonymous.”
There are other reasons your doctor may perform a speculum exam, like unusual discharge, bleeding or infection.
As for the women who aren’t going in for routine Pap smears, low access to medical care can be a barrier, especially for women without insurance or those living in areas with a limited number of healthcare providers. Title X Family Planning Clinics and organizations like Planned Parenthood are both good options for uninsured and underinsured women, Cepin says.
A 2017 study also found that cervical cancer screenings drop off as women near age 65. But an older woman who hasn’t had a hysterectomy is at least as likely to get cervical cancer as a younger woman, according to the study.
Part of the problem is that women tend to stop going to the ob-gyn when they don’t want kids anymore, or after menopause, Harper says. Another deterrent for older women is the physical discomfort of Pap and HPV testing, but Harper says she’s hopeful that self-sampling HPV tests could one day eliminate the need for invasive exams.
“If we could do that, we could get the test into geriatrician and general physician offices so these women can get screened more easily,” she says. “Speculum exams are not very comfortable once people get past 60. Hopefully we can change that and increase the screening rate.”
Plan on yearly visits, even without a Pap smear
Although some women can wait as long as five years between cervical cancer screenings, Barroilhet urges women to continue going in for yearly check-ups with their gynecologists.
“Every year, we should still have an internal pelvic exam,” she says. “Just because we’re not getting a Pap smear does not mean we can’t see our physicians.”
This story has been updated to reflect changed FDA guidelines for HPV vaccination.