Are Pap Tests Accurate?

Posted on January 14, 2013 by Anna C.

If you follow health news, you might have noticed some controversy over certain cancer-screening methods: Does the evidence support mammograms as a tool to reduce breast cancer deaths? Are PSA tests effective in saving lives from prostate cancer? These are questions that we are beginning to answer as more and more evidence comes in. But don’t let these questions dissuade you from all cancer screening.

With regular Pap testing, cervical cancer is almost 100 percent preventable.

In fact, although we’re reevaluating data for other cancer-screening methods, we have mountains of solid evidence that the Pap test is one of the best cancer-screening methods out there. Because it detects signature mutations that mark cells as headed toward becoming cancerous, Pap testing detects “pre” cancer while other cancer-screening techniques, like mammography, only detect cancer.

Cervical cancer used to be a top killer in developed nations — and it remains a major cause of death in countries without widespread health-care access — but in the last 50 years, cervical cancer deaths fell by 70 percent in the United States, transforming cervical cancer from the leading cause of cancer death among American women to a less common, nearly preventable cancer. Despite this, you might hear people complain that the Pap test isn’t accurate, citing the possibility of receiving “false positive” or “false negative” results.

A Pap test looks for abnormalities in cervical cells, and you can receive one of these four results:

True Positive: Cellular abnormalities are detected, and they are in fact present.	True Negative: Cellular abnormalities are not detected, and in fact the cells are normal.
False Positive: Cellular abnormalities are detected, but the cells are actually normal.	False Negative: Cellular abnormalities are not detected, but are actually present.

When we receive a true positive result, we can receive treatment for precancerous lesions that in fact might otherwise lead to cancer. Likewise, when we receive a true negative result, no further treatment is needed. Continue reading →

Interpreting Abnormal Pap Tests

Posted on November 28, 2012 by Tori

Because a Pap test screens for abnormal cervical cells and because those cell changes can be associated with cervical cancer, being on the receiving end of an abnormal Pap test result can be frightening, intimidating, and confusing.

On the “frightening” aspect: Some people assume that an abnormal Pap means that cervical cancer is imminent. On the contrary, the National Cancer Institute not only states that cervical cancer, when it develops, takes “many years” to do so, but also that “[t]he majority of infections with high-risk HPVs [human papillomaviruses] clear up on their own.” This is not to suggest that regular screenings aren’t important — but rather, that they do their job and detect cervical changes in plenty of time to prevent cancer from developing in the first place.

Remember that if you’re confused about your Pap test results, part of your health care provider’s job is to answer your questions and keep you informed.

On the “confusing”: It’s true. There are a lot of different letter codes. Though some of them look awfully similar, they each mean a different thing. Moreover, the clinical recommendations for how to follow up with an abnormal Pap can depend not only on the code — in other words, the specific abnormal result — but also on one’s age and medical history.

Ready to sort them out?

Most labs in the United States use a classification system called the Bethesda System in order to have some standard terminology when reporting results. The Bethesda System uses the term squamous intraepithelial lesion to describe changes on the surface of the cervix. It categorizes those changes in these ways: Continue reading →

How Often Do I Need a Pap Test?

Posted on September 4, 2012 by Rebecca

Editor’s Note: In August 2018, the U.S. Preventive Services Task Force updated their recommendations to allow patients 30 to 65 years of age to receive HPV testing alone every five years — without an additional Pap test.

Almost 80 years ago, Dr. George Papanicolaou developed a simple test, the Pap test (also called the Pap smear), done in a doctor’s office to check for cervical cancer. During a pelvic exam, a doctor swabs a small sample of cervical tissue and looks for abnormal cells. If these precancerous cells are detected, it will lead to more tests or other more invasive treatments such as a colposcopy (in which actual tissue may be removed). In the 1930s, when Papanicolaou was developing his test, cervical cancer was more lethal than breast cancer. But since the development of this test, the number of women dying from cervical cancer has dropped dramatically. In 2009, of the 4,000 women in the United States who died of cervical cancer, most had never been screened or had not been screened in the 10 years before their diagnosis.

This year, the U.S. Preventive Services Task Force recommended less frequent Pap testing.

Cervical cancer is most common in women between ages 35 and 55, and usually develops from a human papillomavirus or HPV infection. Not all HPV infections lead to cervical cancer, and it can take decades for a persistent infection with a high-risk type of HPV to become cancer. High-risk HPV types are sexually transmitted and can lead to cervical cancer and also anal, penile, and oral cancers.

There are two types of screening: Pap tests and HPV tests. While they both require a pelvic exam in which cells are taken from the cervix, Pap tests look for abnormal or precancerous cells, and HPV tests look for DNA or RNA from high-risk HPV types in cervical cells. Both tests are used to try to catch cervical cancer in its earliest stages so that it can be successfully treated. Continue reading →

Over 90 Percent of What Planned Parenthood Does, Part 7: Pap Testing

Posted on August 28, 2012 by Anna C.

Low-grade lesions of cervical cells, which can be treated before progressing to cancer. Image: National Cancer Institute

Welcome to the latest installment of “Over 90 Percent of What Planned Parenthood Does,” a series on Planned Parenthood Advocates of Arizona’s blog that highlights Planned Parenthood’s diverse array of services — the ones Jon Kyl doesn’t know about.

Pap tests are not beloved — there, I said it. Many people who receive them hope for the day that medical science devises an equally effective but noninvasive test, whatever that might entail, as they may find them to be anything from slightly awkward to incredibly traumatizing. However, the evidence overwhelmingly shows that access to Pap testing (also called Pap smears) has transformed cervical cancer from a top killer into something that can be caught early and treated before it can do much damage. As a tool to reduce cancer deaths, Pap tests have been a resounding success.

In countries with widespread access to Pap tests, cervical cancer rates have plummeted.

A Pap test involves an instrument called a speculum being placed into the vagina to hold it open while a health care provider uses a small spatula or a tiny brush to collect cells from the cervix, which is at the opening of the uterus. These cells are analyzed in a laboratory, where a technician can determine if they are precancerous. (Cervical cancer is caused by a sexually transmitted virus called human papillomavirus, or HPV.) When caught in its precancerous stages, cervical cancer can be treated with procedures such as colposcopy and cryotherapy.

Pap testing guidelines have recently changed. Continue reading →