ABNORMAL PAP TESTS

The test used to detect cervical cancer is called a Pap test, named for Dr. George Papanicolaou. The Pap test detects changes in the cervix that could be a sign of cancer or precancer (changes that could lead to cancer.) It is a screening test. The Pap test detects possible signs of disease in women who do not have symptoms such as bleeding, pelvic pain, or discharge.

The Pap test has been very successful in decreasing deaths from cervical cancer. Before a woman gets cervical cancer, she may go through several stages of pre-cancer. This usually happens over a number of years. Because the precancer cells are right on the surface of the cervix, the Pap test can pick up precancer before cancer grows. If abnormal cells are found, they often can be treated with simple procedures in the doctor's office.

This web page will explain how the Pap test is performed, and how the test results are studied, classified, and reported.






A Regular Part of Your Health Care

A Pap test done on a regular basis is a key part of your overall health care. You should have your first Pap test by age 18 or when you start sexual activity - whichever comes first. Most doctors feel that a woman should have an exam, including a Pap test, every year. If your tests show abnormal results or if you have had cancer, your doctor may advise you to have a Pap test more often.

Some women are at increased risk for developing cervical changes. You may be at increased risk if any of the following applies to you:

  • You have had more than one sexual partner or a sexual partner who has had more than one partner
  • You have had genital warts or infection with human papillomavirus (HPV)
  • You are infected with human immunodeficiency virus (HIV) infection
  • You smoke

If you have any of the above risk factors, it is even more important for you to have a Pap test each year.

If you have no risk factors, and have had three normal tests in a row, you may be able to have the test done less often. Less frequent testing should be based on your doctor's advice. It only applies if your risk factors don't change. Even if your doctor decides you don't need a Pap test every year, you should still see your doctor each year for a pelvic exam.


The Cervix

The cervix is the lower, narrow end of the uterus. It opens into the vagina.

The cervix is covered by a thin layer of tissue like your skin. The cells that make up this tissue grow all the time. During this growth, the cells at the bottom layer slowly move to the surface of the cervix. When these cells reach the surface, they are shed as a normal process.

When this normal process is changed in some way, cells become abnormal. Sometimes the abnormal cells can lead to cancer.



The Pap Test

The Pap test can be performed in a doctor's office during a pelvic exam. If you are planning to have a Pap test, do not douche or use vaginal medication for 2-3 days beforehand. This may wash away or hide any changed cells. The Pap test is more accurate when you are not having your period.

During your pelvic exam, your doctor will insert a speculum into your vagina. This instrument gently opens the vagina so the cervix can be seen. A small brush or swab and scraper are used to remove cells from the cervix. This is not painful. Cells will be taken from inside the opening of the cervix and from the outer part of the cervix. They are sent to a lab to be tested. A specially trained technician or doctor looks for cells that do not appear normal. The results are classified based on how the cells look. Your doctor is then informed of the results.


Normal Pap Results
Cells are light in color, and each nucleus, or cell control center is tiny.
Inflammation (Class II)
Cells may be darker. The nucleus of some cells may be slightly larger.
Low-grade SIL (Class III; CIN I-II)
Overall cell size is the same, but the nucleus is larger.
High-grade SIL (Class IV; CIN III)
The nucleus is big and darker in color, but may still have a normal shape.
Cancer (Class V)
Cells vary in size. Some may be dividing. The nucleus is oddly shaped.


The Results

The results are most often classified by a system developed by the National Cancer Institute (NCI). It is called the Bethesda System and is named for the town in Maryland where NCI is located. It outlines terms to be used in a diagnosis:

  • Normal: This result means that only normal cells are seen.
  • ASCUS (Atypical squamous cells of undetermined significance): This result means that the cells may not be normal. It is hard to tell exactly what is wrong with them.
  • Squamous intraepithelial lesion (SIL): This result means that the cells that were tested show certain distinct changes. These changes are also called dysplasia or cervical intraepithelial neoplasia (CIN). There are three grades of each of these (see graphic below). SIL is classified as low grade or high grade.
    1. Low-grade SIL includes mild dysplasia (CIN 1) and changes linked to HPV. HPV is a virus that may cause genital warts. Some types of it have been linked to cervical cancer.
    2. High-grade SIL includes moderate to severe dysplasia (CIN 2 and 3) and carcinoma in situ (CIS). CIS, although not a true invasive form of cancer, is a precancer that must be treated.
  • Cancer: This result means that the cells have progressed beyond dysplasia (CIN) and have become invasive.



Is the Pap Test Always Accurate?

The Pap test finds dysplasia and cancer of the cervix. It is not 100% accurate, though. Like any lab test, false results are possible.

False-negative results are reports of normal test results when there are abnormal changes. This occurs in 10-20% of all Pap tests. False-negative results can occur for a number of reasons:

  • Not enough cells
  • Too many cells
  • Cells not taken from both the inside and surface of the cervix
  • An infection "covers up" abnormal cells
  • Douching or vaginal medicines have "washed away" abnormal cells
Because Pap test results are based on how a slide looks, even experts may disagree. Sometimes the reason for a false-negative result is not known.

False-positive results can also occur. This means that abnormal cells were reported but the cells were really normal. This is rare.

Any abnormal finding or a finding of ASCUS showing that cells may not be normal requires further tests. This may be a simple as a repeat Pap test in a few weeks or months. Sometimes your doctor will do an exam called a colposcopy to decide if you need treatment. Colposcopy is done in your doctor's office with a special microscope called a colposcope. By looking at the cervix through a colposcope, your doctor may be able to see the changes that cause the abnormal Pap test result.

Colposcopy may help the doctor decide whether a cervical biopsy needs to be done and if so, what kinds. (In some cases, a doctor may do a biopsy even if nothing is seen on colposcopy.) A biopsy removes some of the abnormal cells for further study. It is usually done in the doctor's office or clinic. It may cause slight discomfort for a few seconds.

There are several types of biopsies. Your doctor may perform one of the following:

  • Punch biopsy: A small sample of the cervix is removed with a special instrument.
  • Endocervical curettage: A sample is removed from the inside part of the cervix with a small instrument shaped like a spoon.
  • Endometrial biopsy: A small amount of the tissue lining the uterus is removed.
  • Cone biopsy: A cone-shaped wedge of tissue is removed from the cervix. This type of biopsy is used if a larger sample is needed.
Because abnormal areas are removed, sometimes a biopsy will also serve as a method of treatment.

One method of treatment is cryotherapy. Cryotherapy is an office procedure used to treat abnormal cells on the cervix. It is usually done during the first week after a menstrual period. It takes only a few minutes, so you should be in and out in less than an hour. During cryotherapy, the abnormal tissue is frozen. This tissue dies, and the tissue that grows back is most often normal. There is no cutting or bleeding. You may be given medication to take ahead of time to relieve any cramping you might feel during the treatment.


And In Conclusion...

The Pap test is the best way to find conditions that may lead to cervical cancer. By treating precancer, cervical cancer can usually be avoided. The Pap test may find problems before you are aware that anything is wrong.

See your doctor once a year for a pelvic exam. For most women, this visit will include a Pap test. Be sure to see your doctor right away if you notice abnormal vaginal spotting, bleeding or discharge. These are signs that something might be wrong.

If you do have an abnormal Pap test, do not panic. Follow your doctor's advice. Only a small number of women with abnormal Pap test results have invasive cancer. Thanks in part to the Pap test, deaths from cervical cancer have decreased over the last 40 years. However, the rate of abnormal cells found in Pap tests in young women is rising. This means that the Pap test is more important than ever to prevent an increase in cervical cancer. By understanding the Pap test and how results are reported, you can take an active part in your health care.