Cervical Cancer; Diagnosis.
Despite the Pap test's 50-year record as a safe and highly accurate screening tool for cervical cancer and precancerous abnormalities of the cervix, many women do not have regular Pap tests. In fact, as many as 35 percent of women between the ages of 15 to 44 forgo this vital screening, according to the Planned Parenthood Federation and the U.S. Centers for Disease Control and Prevention (CDC). And, in fact, half of all newly diagnosed women with cervical cancer have never had a Pap test, and 10 percent haven't been screened within the past five years.
A Pap test is a simple procedure: After a speculum (the standard device used to examine the cervix) is placed in the vagina, cells are skimmed from the surface of the cervix with a cotton swab then smeared onto a glass slide. Another sample is taken from the T-zone (or the transition-zone, the area of transition between cervical cells and uterus cells) with a tiny wooden or plastic spatula, or a tin brush. Newer techniques called "liquid-based" Pap tests may provide a higher degree of accuracy and reliability.
The cervix is the narrow neck of the uterus that opens into the vagina. For women who have had total hysterectomies, in which the cervix is removed, cells are taken from the walls of the vagina. Women who have had a hysterectomy should continue to have a Pap test every two to three years until age 65 or 70 if they had a history of high grade squamous intraepithelial lesions before they had the hysterectomy. After age 70, they can discontinue screening after three consecutive normal Pap tests.
The slide is delivered to a laboratory where a cytotechnologist (a lab professional who reviews your Pap test slides) and, when necessary, a pathologist (a health care professional who examines bodily tissue samples) examines the sample for any abnormalities. Each smear contains roughly 50,000 to 300,000 cells.
Though not infallible, when performed properly the Pap smear detects a significant majority of cervical cancers--usually in the early stages when the likelihood of a cure is greatest, according to the American Society of Clinical Pathologists.
New Technology for Cervical Cancer Screening and Diagnosis
Because the Pap test can be associated with sampling and interpretation errors, research and development strategies are focused, to a large degree, on fine-tuning Pap test interpretation, visualization and tissue retrieval. The U.S. Food and Drug Administration has approved a number of devices to enhance the Pap test. Here's an overview of the new technology designed to improve accuracy of the Pap smear:
Newer liquid-based Pap tests such as ThinPrep and SurePath use a solution that helps preserve the cells scraped from the cervix (the Pap smear), as well as remove mucus, bacteria and other cells from the specimen that may interfere with examining the cervical cells. Test vials preserve specimens for up to three weeks from the date of collection, giving the physician an opportunity to request HPV testing on a patient if a borderline Pap test results.
The tests improve the detection of many lesions and reduce the need for unnecessary repeat tests.
Other technology includes:
AutoPap 300 QC Automatic Pap Screener System: a fully automated quality control system that re-screens all Pap smear slides for fewer false-negative results--when tests fail to detect existing abnormalities.
Cervicography: creates enlarged photographs of the cervix to be used along with Pap tests.
papnet Testing System: a computer system that selects the 128 worst cells obtained by the Pap test for evaluation by a cytologist.
papSure: a cervical screening device with a tiny light attached to the speculum that enables a health care professional to directly visualize abnormalities at the time of the pelvic exam. The blue light on papSure is designed to cause abnormal tissue to appear bright white.
Pathfinder System: an automated computer-based microscope that helps cytotechnologists identify, mark and record suspicious cells on Pap tests.
These tests were designed to more accurately interpret Pap smear slides and to reduce the incidence of false negative results.
Because some HPV subtypes can be a predictor of the presence or future development of cervical cancer, many medical professionals now also test for this disease as an adjunct to the Pap test. One test now available is:
Hybrid Capture II. This test uses DNA-based technology to detect HPV. It can be performed at the same time as a Pap test and in the same manner, with a swab of cells scraped from cervical tissue. In March 2003, the FDA expanded the use of the test to include screening, in conjunction with the Pap test, of women over age 30 for HPV infection. It should be used along with a complete medical history and an evaluation of other risk factors to help physicians determine what kind of follow-up to the Pap may be necessary.
To help improve the reliability of your Pap test, schedule your appointment two weeks after your last menstrual period and refrain from doing the following for at least 48 hours before the test:
Using vaginal creams, suppositories, medicines, sprays or powders
Pap Test Results
An abnormal Pap test result does not mean you have cervical cancer. It indicates some degree of cellular change in the cells that cover the surface (lining or epithelium) of the cervix.
While the Pap test cannot reliably confirm a herpes infection, it can indicate infection with HPV.
Pap test classifications include:
Another type of cellular change reported by a Pap test is considered precancerous. The term squamous intraepithelial lesion (SIL) is used to identify this type of cellular change. SIL changes are divided into two categories: low-grade SIL and high-grade SIL.
Benign (noncancerous) cellular changes. These result from inflammation caused by a number of things, including diaphragm use or infection with trichomonas, a sexually transmitted vaginal infection.
Atypical squamous cells of undetermined significance, or ASCUS. These cellular changes appear abnormal for unknown reasons. It isn't possible to determine if the abnormality is caused by inflammation, infection or by precancerous changes. These types of cellular changes usually return to normal without intervention or after treatment of an infection. Follow-up for this Pap test result is usually a repeat Pap test in three to six months.
Squamous intraepithelial lesion (SIL). This change is considered precancerous. SIL changes are divided into two categories: low-grade SIL and high-grade SIL.
Low-grade SIL refers to early changes in the size, shape and number of cells on the surface of the cervix. Most of these lesions return to normal on their own without treatment. Others, however, may continue to grow or become increasingly abnormal in other ways and develop into a high-grade lesion.
Other terms for low-grade SIL are mild dysplasia or cervical intraepithelial neoplasia 1 (CIN 1). According to the National Cancer Institute, these precancerous changes occur most often in women ages 25 to 35, but can appear in other age groups, as well.
Generally, your health care professional will recommend a diagnostic test as a follow-up if your test is categorized as low-grade SIL/CIN I, including colposcopy and biopsy.
High-grade SIL. Cells in this category look very different from normal cells and are less likely to return to normal without treatment and more likely to develop into cancer. These abnormal cellular changes are still confined to the surface of the cervix only and still are considered precancerous changes. High-grade SIL is most common in women age 30 to 40, but can occur in other age groups, as well.
Other terms for high-grade SIL are moderate or severe dysplasia (CIN 2 or CIN 3) carcinoma in situ.
Follow up for high-grade SIL/CIN 2 or CIN 3 involves additional procedures, including biopsy, to determine the degree of abnormality and rule out invasive cancer.
Usually, cervical cancer grows slowly. Precancerous changes may not become cancerous for months or years. Once they spread deeper into cervical tissue or to other tissues and organs, the cellular abnormalities are classified as cervical cancer, or invasive cervical cancer. Cervical cancer tends to occur in midlife; half of women diagnosed with cervical cancer are between the ages of 35 and 55, and it rarely occurs in women younger than 20.
A Pap test is a screening tool; other procedures are necessary to confirm Pap test abnormalities and diagnose conditions. All abnormal Pap tests should have some form of follow-up. This may include a "watch and wait" approach with retesting in several months. Or, depending on the degree of abnormality, your health care provider may order other tests, including:
Colposcopy: The doctor uses a colposcope to magnify and focus light on the vagina and cervix to view these areas in greater detail. Depending on these findings, your health care professional may then use one or more of the following tests:
Biopsy: During this procedure, sample tissue is taken from the cervical surface. Often several areas are biopsied.
Endocervical curettage: Cells are scraped from inside the cervical canal using a spoon-shaped instrument called a curette to help make a more precise diagnosis. This procedure evaluates a portion of the cervix that cannot be seen.
Cone biopsy: When biopsy or endocervical curettage reveals a problem that requires further investigation, a cone biopsy may be performed. A "cone" of tissue is removed from around the opening of the cervical canal. In addition to diagnosing an abnormality, cone biopsy can be used as a treatment to remove the suspect tissue.
Loop Electrocautery Excision Procedure (LEEP): The suspicious area is removed with a loop device and the remaining tissue is electrocoagulated (vaporized with radio waves). LEEP is both a diagnostic test and a treatment. A pathologist examines tissue removed during LEEP.
If cancer of the cervix is diagnosed, more tests will be conducted to learn if cancer cells have spread to other parts of the body. These tests may include:
Cystoscopy: This test is performed to see if the cancer has spread to the bladder. The doctor examines the inside of the bladder using a lighted tube.
Proctoscopy: Similar to a cystoscopy, this test is performed to see if the cancer has spread to the rectum.
Examination of the pelvis under anesthesia to further check for spread.
Chest x-ray to see if the cancer has spread to the lungs.
Other imaging tests such as CT (computed tomography) scans to see if the cancer has spread to lymph nodes or other organs.
Your past Pap test results and personal health history will help your health care professional determine what type of follow up is appropriate.
In some cases, a Pap test may report that abnormal cells are present in a sample when, in fact, the cells in question are normal. This type of abnormal report is known as a false positive.
When a Pap test fails to detect an existing abnormality, the result is called a "false negative." Even under the best of conditions, there is always a small, but irreducible, false negative rate. Several factors may contribute to a false negative Pap test:
When irregular cells are located high in the cervical canal they are difficult to access under normal Pap test procedures.
Menstrual blood and inflammatory cells can mask abnormal cells; these cells would not be visible to the cytotechnologist.
An inadequate sample--not enough cells were collected during the Pap test.
Human error, in which the person reviewing the slide misinterpreted abnormal cells as normal.
Screening Guidelines for Cervical Cancer from American Cancer Society
Screening should begin about three years after a woman begins having intercourse, but no later than age 21.
Women should have a regular Pap test every year or a liquid-based Pap test every two or three years. At or after age 30, women who have had three normal test results in a row may be screened every two to three years. A health care professional may suggest more frequent testing if you have certain risk factors such as human immunodeficiency virus (HIV) infection or a weakened immune system.
The combination of HPV testing with a Pap test should be considered as an alternative for routine screening in women 30 and older.
Women age 65 to 70 and older who have had three or more normal Pap test results and no abnormal results in the last 10 years may stop screening.
Screening after a total hysterectomy (with removal of the cervix) is not necessary unless the surgery was performed as a treatment for cervical cancer or pre-cancer, or there was a prior history of abnormal Pap smears. Women who have had a hysterectomy without removal of the cervix should continue cervical cancer screening at least until age 65-70.
"FDA Licenses New Vaccine for Prevention of Cervical Cancerand Other Diseases in Females Caused by Human papillomavirus. Rapid Approval Marks Major Advancement in Public Health." June 8, 2006. Press release. http://www.fda.gov.
Checkup: Cervical Cancer. Wall Street Journal Online. September 10, 2004. Available at: http://online.wsj.com. Accessed September 10, 2004.
"Task Force Announces New Cervical Screening Guidelines." American Cancer Society. http://www.cancer.gov. Created January 22, 2003. Accessed September 9, 2004.
"New Cervical Cancer Early Detection Guidelines Released." American Cancer Society. http://www.cancer.org. Created November 20, 2002. Accessed September 9, 2004. Also see "Task Force Announced New Cervical Cancer Screening Guidelines." National Cancer Institute. http://www.cancer.gov. Created January 22, 2003. Accessed September 9, 2004.
"Pap Test. Detecting Precancerous Lesions." American Cancer Society. http://www.cancer.org. Accessed September 9, 2004.
"Overview: Cervical Cancer." American Cancer Society. http://www.cancer.org, Accessed September 9, 2004.
" Cervical Cancer." CancerNet. National Cancer Institute. National Institutes of Health. http://www.cancer.gov. Accessed September 9, 2004.
"Fact Sheet: Human Papillomavirus and Genital Warts." National Institute of Allergy and Infectious Diseases. Office of Communications and Public Liaison. July 2004. http://www.niaid.nih.gov. Accessed September 2004.
"Fact Sheet: Genital HPV Infection." Centers for Centers for Disease Control and Prevention. Updated August 2004. http://www.cdc.gov. Accessed September 8, 2004.
American Cancer Society. Cancer Facts and Figures, 2004..Available at: http://www.cancer.org. Accessed September 9, 2004.
"FDA Approves Expanded Use of HPV Test" U.S. Food and Drug Administration. March 31, 2003. http://www.fda.gov. Accessed September 9, 2004.
"Update on Cervical Cancer Screening" Postgraduate Medicine Online. Vol. 13, No. 2, Feb. 2003. http://www.postgradmed.com. Accessed September 2004.
"New SurePath Pap Test is More Beneficial to Silver Cross Patients/Physicians" Silver Cross Hospital. Aug. 2002. http://www.silvercross.org. Accessed September 9, 2004.
Waggoner SE. Cervical cancer. Lancet. 2003 Jun 28;361(9376):2217-25. Review.
American Cancer Society. Detailed Guide: Cervical Cancer. Available at: http://www.cancer.org. Accessed August 17, 2004.
New Cervical Cancer Fact Sheet. Centers for Disease Control. Available at : http://www.cdc.gov. Accessed August 4, 2004.
Gynecologic Cancers. NWHRC Health Report, August 2004.
Koutsky LA, Ault KA, Wheeler CM, Brown DR, Barr E, Alvarez FB, Chiacchierini LM, Jansen KU; Proof of Principle Study Investigators. A controlled trial of a human papillomavirus type 16 vaccine. N Engl J Med. 2002 Nov 21;347(21):1645-51.
"Detailed Guide: Cervical Cancer. Treatment Options by State." American Cancer Society. October 31, 2005. http://www.cancer.org. Accessed February 2006.
"Immunotherapy for Specific Cancers." The American Cancer Society. April 11, 2005. http://www.cancer.org. Accessed February 2006.
Keywords: cervical cancer, symptoms, pap test, pap smear, pap test result, pap test results, bethesda system, hpv, abnormal pap, sil, low-grade sil, high-grade sil, colposcopy, biopsy, cone biopsy