A Pap smear (also called the Pap test) is a simple medical procedure during which samples of cells from a woman’s cervix are examined under a microscope to look for pre-malignant (before-cancer) or malignant (cancer) changes. In most cases, Pap smears identify cellular abnormalities before they become malignant so they are more easily treatable.
It is named after Greek Dr. George Papnicolaou who discovered that with the test cellular abnormalities could be detected before the tumor became invasive and thanks to Pap smear, cervical cancer dropped from first to third place as a cause of cancer death in women.
Women should start having Pap smears within 3 years of first sexual activity or age 21, whichever comes first.
About how often should be performed:
- American college of Obstetrics and Gynecology recommend it every year until age 30 and then if three annual Pap results were normal it can be done every 2-3 years
- American cancer society recommends it every year with exceptions: every 2 years if liquid-based kit and every 2-3 years if three normal tests in a row in women >30 years old
- US Preventative Services Task Force 2003 recommend it at least every 3 years
Women who have had a total hysterectomy for a benign condition should not have Pap smear.
At increased risk for having an abnormal Pap smear are women with infection with the genital wart virus called the human papillomavirus (HPV), women whose mother took the drug diethylstilbestrol (DES) during pregnancy, women with weakened immune system by medications, women who are smoking and women with multiple sexual partners and women who become sexually active at a young age.
Pap smear should be done when a woman is not menstruating. Also, a woman should at least two days before the test avoid spermicidal creams, foams or jellies or vaginal medicines because they can hide or wash away any abnormal cells.
During the procedure, a woman lies on her back on an examining table with the feet elevated in stirrups. A speculum is inserted to open the vaginal area with a small cervical brush, the first sample is taken and the second sample is taken from a scraping of the area surrounding, but not entering, the cervical os. Both samples are smeared on a glass slide for laboratory evaluation.
The doctor will perform a physical exam. With two fingers on one hand, the doctor will insert inside the vaginal canal and with the hand on top of the abdomen, he/she will feel the ovaries and uterus.
After the exam, the doctor will inform the woman when the results will be available and this is usually within two to three weeks.
A Pap smear report include:
- The name of the woman
- The name of the pathologist and/or the cytotechnologist who read the smear
- The source of the specimen (in this case, the cervix)
- The date of the last menstrual period of the woman or the note that women are no longer menstruating
- The woman's relevant medical history (example, "history of genital warts")
- The number of slides (either one or two, depending on the health care practitioner's routine practice)
- A description if the sample is satisfactory for interpretation
- The final diagnosis and the recommendation for follow-up
Abnormal Pap smears are categorized by medical terminology system called The Bethesda System as:
- ASC-US (atypical squamous cells of undetermined significance)
- LSIL (low-grade squamous intraepithelial lesion)
- HSIL (high-grade squamous intraepithelial lesion)
“Squamous” means the thin, flat cells which lie on the surface of the cervix, “intraepithelial” means that the surface layer of the cells is affected and “lesion” means that abnormal tissue is present.
If a Pap smear is interpreted as abnormal, there are a number of different management and treatment options including:
- Laser therapy
- Large loop excision of the transformation zone
All of these procedures have essentially the same overall cure rate of over 90%. However, the procedures do vary considerably in a number of other respects and so will be discussed separately.
It is important that women recognize that it is important to have regular Pap smears because between 60% and 80% of American women who were newly diagnosed with invasive cervical cancer have not had a Pap smear in the past five years and may never have had one.