Pap smears are screening tests for cervical cancer in which a swab introduced into the vagina is used to collect cell samples. Pap smears have been instrumental in decreasing the number of cases of cervical cancer in North America by detecting a precancerous condition called dysplasia.

Dysplasia is an alteration in the skin of the cervix, vagina, vulva or anus that has the potential to progress to cancer if left untreated. It usually doesn’t cause any symptoms but sometimes can be associated with abnormal bleeding or spotting.

Pap smears are an excellent way to detect dysplasia of the cervix, which is the most common site for dysplasia in women. The test is the most effective form of cancer prevention available to women. It has recently been adapted as a screening test for the anus, to detect anal dysplasias and cancer. It is recommended that females, age 25 to 65, who have had sex get regular Pap smear tests. Guidelines on test frequency vary, from annually to every five years.

In North America, about 2-3 million abnormal Pap smear results are found each year. Sometimes, pap smears can be abnormal when there are no pre-cancerous conditions present. Some common types of abnormal pap smears are:

• Insufficient — There was not enough material to ensure that no abnormal cells were present.
• Obscuring — There was an infection or bleeding that limited the pathologist’s ability to read the pap smear.
• Atypical — The cells don’t look quite normal, but it is difficult to tell what exactly is going on.

Once dysplasia has been detected on a pap smear, the genital area should be examined under magnification — a procedure known as colposcopy — to identify exactly where the dysplasia is located, followed by removal of the dysplasia if indicated.

There are a number of ways to remove the abnormal cells created by dysplasia. They include:

• Loop excision — This technique uses a fine wire loop with electrical energy flowing through it to remove the abnormal area of the cervix. The removed tissue is sent to the laboratory for examination.
• Cone biopsy — This is an outpatient surgical procedure in which a cone-shaped section of the cervix is removed using a scalpel. The tissue is then sent to the laboratory for examination.
• Laser therapy — Laser therapy uses a tiny beam of light to vaporize abnormal cells. The laser is directed through a colposcope so that the area and depth of treatment can be controlled precisely.
• Cryotherapy — In cryotherapy, a probe is used to cool the cervix to sub-zero temperatures. The cells damaged by freezing are shed over the next month in a heavy watery discharge.

For other abnormal pap smears, the next step usually is to repeat the test. Sometimes, the practitioner will prescribe antibiotics or hormones, either oral or vaginal, before repeating the pap smear.