Women's Bodies, Women's Wisdom (63 page)

Pap Smear Screening

The Pap smear is the single most cost-effective disease screening test known to modern medicine. Ever since the Pap smear was introduced by George Papanicolaou, M.D., in the late 1940s, the incidence of invasive cervical cancer and the death rates from this disease have gone down dramatically. In fact, it is estimated that 70 percent of cervical cancer deaths are actually prevented because of this inexpensive and noninvasive test. The results are so impressive that I’ve often joked about the need for a drive-through Pap test center that would make the test as easy to obtain as a McDonald’s meal.
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A Pap smear is made by taking a sample of cells from the transformation zone in the squamocolumnar junction (SCJ) of the cervix, up inside the cervical opening. The cells are fixed onto a slide by spraying them or covering them with a cell-preserving chemical.

Newer liquid Pap tests such as ThinPrep, in which cervical cells are placed in a test tube of liquid media, have now replaced the conventional Pap smear in many areas. ThinPrep makes it easier to evaluate cervical cells because the liquid media keeps them from drying out. It also filters out debris before the cells are placed on a slide. Studies performed by the manufacturer suggest that the ThinPrep test improves the detection of abnormal cells by 65 percent and reduces the number of less-than-adequate smears by 50 percent when compared with regular Pap smear techniques.
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Having this information doesn’t necessarily change the treatment. ThinPrep increases the chance of finding abnormalities that in many cases are benign. It also may double the price of a Pap test.

Pap smear testing is not perfect: Cervical cancer has not yet been completely eradicated. But we’re gaining. About 3,700 women still die from this condition annually in the United States—not all of whom failed to get a regular Pap smear. Let me put this figure into perspective: Every year 435,000 people die from alcohol use, 365,000 die from poor diet and inactivity, and 7,600 die from aspirin and nonsteroidal anti-inflammatory drug use.
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The number of deaths from cervical cancer every year in the United States is very low (in developing countries, the rate is much higher)—especially compared with the amount of worry about abnormal Pap smears.

Abnormalities from the upper genital tract, the endometrium, the fallopian tubes, and occasionally the ovaries may show up on Pap smears, but only rarely. The Pap smear screens for cervical abnormalities only. Many women don’t understand this limitation in their health care practitioner’s ability to diagnose problems.

The American College of Obstetricians and Gynecologists updated its Pap smear screening recommendations in 2009. Here are the current recommendations:

Women ages twenty-one to twenty-nine.
Women should have their first cervical cancer screening (a Pap smear or liquid-based cytology, such as the ThinPrep Pap) at age twenty-one, regardless of when they begin having sex. After that, they should have subsequent screenings every two years until they reach age 30. (The old guidelines, in contrast, called for annual screenings.) Note that the HPV DNA test is not recommended in women younger than thirty. That’s because any HPV changes in their cervix generally resolve on their own by the age of thirty.

Women ages thirty to sixty-five or seventy.
Women who have had three consecutive negative cervical cancer screenings can have subsequent screenings every three years, instead of the previously recommended every two to three years.

Women over age sixty-five to seventy.
Women who have three or more negative cytology results in a row and no abnormal test results in the past ten years may be able to stop having cervical cancer screenings.

Special cases.
(1) Women of any age who are immunocompromised, are infected with HIV, or were exposed in utero to DES should have annual cervical cancer screenings. (2) Most women who have not had abnormal cervical cell growth but who have had a hysterectomy with removal of the cervix for other reasons may discontinue routine Pap smears. However, even if they have had a hysterectomy, women who have had a history of abnormal cell growth (classified as CIN 2 or 3) should have annual Pap smears until they have three consecutive negative Paps; then they can discontinue routine Paps.

ACOG still recommends that women have annual gynecological exams, even in years when they do not have Pap tests. Furthermore, it is very important for women who have had the HPV vaccine to continue to follow the same screening guidelines as unvaccinated women since the HPV vaccine does not protect against all forms of HPV, and women who have had it can still get cervical cancer (see discussion of the HPV vaccine on page 273).

ACOG previously recommended that cervical screening begin three years after the first time a woman starts having sexual intercourse or by age twenty-one, whichever came first. But statistics show that women under age twenty-one rarely get cervical cancer. If they are sexually active, however, their rates of HPV infection and dysplasia are high. Numerous studies show that women who have a LEEP procedure to treat dysplasia are more likely to have a subsequent preterm delivery. (Not only is the Pap not necessary in this age group, then, but LEEP is also overkill here because the immune system usually clears 90 percent of HPV infections within one to two years.) The bottom line is that young women were being overtreated for dysplasia showing up in Pap tests, potentially compromising the health of their future children. I applaud these changes and concur with them.

I’d recommend a yearly Pap smear if you have had any of the fol lowing:

Infection with HIV (human immunodeficiency virus)

Immunosuppression secondary to organ transplantation (e.g., kidney transplant)

Smoking or regular use of alcohol, cocaine, or other similar substances

A history of abnormal Pap smears, cervical cancer, or uterine, vaginal, or vulvar cancer

Low socioeconomic status (the American College of Obstetricians and Gynecologists points out that this factor appears to be a surrogate for a number of closely related factors that often place these women at greater risk)