Dread Your Annual?
Technological strides have made the Pap smear more accurate than ever
By Phyllis Edgerly Ring
Patricia Rey, 37 years old, has routinely received false positives on her Pap screenings in the past five or six years. Because of this, she must be vigilant about getting the annual test many of us would rather avoid. "It was scary the first time I got one of those atypical results," she says. "My doctor tested me again at three months and has me come in yearly now, as I ought to anyway. Fortunately, my doctor hasn't detected anything else that makes her concerned. The important thing is, if it were a true positive, you wouldn't want them to miss it."
Of the roughly 55 million Pap tests performed in the United States each year, the National Cancer Institute (NCI) estimates that approximately 3.5 million (6 percent) are abnormal and require medical follow-up. Most of these abnormal test results, like Rey's, don't indicate cancer. But Pap tests aren't 100 percent accurate, and both false positives and false negatives do occur. Fortunately, recent advances in technology have improved the Pap test to ensure better detection.
A Proven Record Of Success
The Pap smear has helped make cervical cancer one of today's least-fatal cancers, reducing both its incidence and its death rate by 40 percent since the 1970s. An estimated 13,000 cases were diagnosed in the United States in 2002, when the disease claimed about 4,100 lives. These numbers reflect a 70 percent decline from the mid-20th century, when doctors first introduced the Pap test as a screening tool.
Get Your Pap Test
Did you know the National Breast and Cervical Cancer Early Detection Program, administered by the Centers for Disease Control and Prevention (CDC), provides free or low-cost Pap tests? (Age and income requirements may vary.) For providers in your state, call 888.842.6355 or log onto www.cdc.gov/cancer/nbccedp/contacts.htm. The program also provides information on cervical and breast cancer clinical trials, statistics, and initiatives. Most cervical cancers that occur in the United States today develop in women who've never received screening or who don't receive appropriate follow-up care after abnormal results, according to Alfred Berg, MD, chair of the U.S. Preventive Services Task Force, which helped draw up guidelines for Pap screening. This is one of the major reasons why the routine Pap test remains an important tool, says Carole Hicks, ARNP OB-GYN, site manager of the Planned Parenthood Health Center in Portsmouth, New Hampshire, who recommends regular Pap tests for all women, from teens to grandmothers. "Women can be practiced at overlooking their own needs," she says. "Issues with simple solutions often develop into problems because women don't get checked regularly. The Pap test demands little and delivers a lot."
To perform a Pap test, a doctor collects cells from the cervix; lab technicians then examine the cells for microscopic changes that could be precancerous. The test, named for its developer, George Papanicolaou, MD, enables doctors to detect changes early enough to treat them before cancer develops. These cervical abnormalities don't usually cause pain or other symptoms, so a woman can't usually detect them without having a pelvic exam and a Pap test. (For details on when to get your next Pap smear, see "Screening Basics.")
The main problem with the Pap is that it sometimes gives false positives, causing people like Rey unneeded worry. But false negatives also occur. The Consensus Development Conference on Cervical Cancer, convened by the National Institutes of Health (NIH), concluded that about half of false negatives result from inadequate specimens, and the other half from incorrect identification and interpretation of specimens. Poor-quality specimens can result when inflammation is present, when practitioners collect specimens too close to ovulation, or when noncancerous atypical cells are present. Although a false negative may delay diagnosis and treatment of a precancerous condition, regular screening compensates for this, says Hicks. Luckily, precancerous cells tend to develop slowly into cancerous ones.
The ThinPrep test is around 70 percent accurate, while the traditional Pap test is about 55 percent accurate. The good news is that modern technology has significantly improved the accuracy of Pap screenings. One new method of collection and analysis, called the ThinPrep Pap test, allows a doctor to collect cervical cells with a small brush and place them into a vial filled with preservative fluid, rather than putting them onto the slide used in standard Pap tests. "The solution prevents cells from shriveling," explains naturopathic family practitioner Kristy Fassler, ND, DHANP, of Portsmouth, New Hampshire, "so whole cells are seen under the microscope. It provides a cleaner sample than the dried-up cells associated with slides." Hicks says the accuracy of ThinPrep is around 70 percent, while the traditional slide Pap test is about 55 percent accurate at detecting significant abnormalities.
Other new advances in testing are also promising. AutoPap, an automated test reader, increases accuracy by relaying cellular images to a computer, which analyzes abnormalities a technician might miss. And the recently developed Hybrid Capture II test, which tests for the presence of human papillomavirus (HPV), accurately detected 88.4 percent of the precancerous lesions and 100 percent of the cervical cancers in a study test group. This test, which practitioners can perform at the same time and in the same fashion as a Pap test, can be an especially effective follow-up for detecting both HPV and cervical cancer in women whose Pap screenings have detected abnormalities.
A Significant Risk Factor
Accurate detection of HPV is important because of a new understanding of the link between HPV and cervical cancer. A 1999 study published in the Journal of Pathology (vol. 189, no. 1) documented that the sexually transmitted HPV, varieties of which also produce genital warts, is present in 99.7 percent of cervical cancers. The Centers for Disease Control and Prevention notes there are more than a hundred varieties of HPV and about 50 percent to 75 percent of sexually active men and women will contract genital HPV at some point in their lives.
If these numbers seem high, it's important to remember that only 23 types of the virus affect the genital tract and only 13 key types are linked to cervical cancer. "A person with a healthy immune system can carry a virus the way the body carries the herpesvirus and never have outbreaks or problems," explains Fassler. This means many people who contract the virus never see it produce active infection or lead to cervical cancer. It's therefore important for those who have HPV to focus on strengthening their immune systems and seek help from practitioners who understand what they need to do to accomplish this, she says.
The sexually transmitted HPV is present in 99.7 percent of cervical cancers. In those with healthy immune systems, the virus may even spontaneously regress or leave the body, says Hicks. According to the National Cancer Institute, most HPV infections go away without treatment and don't lead to cervical cancer. However, because HPV infection often shows up years after a person contracts the virus and because the virus often causes no symptoms, it's important that even women in monogamous relationships receive routine Pap tests to determine the health of their cervixes. "Even if they were infected as teenagers, HPV might not show up until their 30s or 40s," explains Hicks.
Clarifying Abnormal Results
Whether HPV puts you at a higher risk for cervical cancer or your risk is low, an abnormal result on a Pap test can be scary. If this happens to you, you might want to know about the three levels of abnormal Pap-test results, says Fassler. "The simplest shows atypical cells whose cause we don't immediately know, or inflammation that causes the atypical cells. We watch this category and test again in three months." (This is the result Rey has periodically received.)
The second stage, in which slight precancerous changes are detected, is called dysplasia, Fassler says. "Not all are serious or dangerous, but guidelines recommend performing a colposcopy, in which we get up close to the cervix with a scope and light and perform a biopsy to see how deep the dysplasia goes.
"Once dysplasia progresses to cancerous cells, the tissue needs to be removed," Fassler says. "The severity of the cancer depends on whether it is simply in the outer cells [carcinoma in situ] or whether it invades into deeper tissues, which is more dangerous." Conventional treatments at this stage include cryotherapy, a procedure that destroys cancerous cells by freezing them, or conization, in which the practitioner removes a cone-shaped piece of tissue using a laser or a knife. Another method is the loop electrosurgical excision procedure, or LEEP, in which an electrical current passes through a thin wire loop that acts as a knife.
For more information on Pap tests and cervical cancer, consult these resources:
National Cancer Institute
Harvard Center for Cancer Prevention
www.yourcancerrisk.harvard.edu One natural alternative or supplemental treatment to such surgery is called escharotic treatment, in which bromelain, a pineapple enzyme, is applied to dysplastic cervical cells, says Fassler. "This approach, which involves eight to ten treatments in a naturopathic doctor's office, works like a tenderizer, eating away cancerous cells without damaging healthy ones. For those women who hope to have children, this treatment helps maintain a competent cervix without the scarring that cryosurgery and conization typically cause."
The numerous advances in screening for cervical cancer are fortuitous for patients like Rey. "I can't say that I look forward to having my Pap test," says Rey. "But even if the readings one day turned out to be truly positive, cervical cancer is a cancer that's treatable and preventable. But not if I don't know whether I have it or not."