14.1. Procedure of Pap Smear Test
A Pap test should not be done when a woman is menstruating. However, Pap smears can be performed during a woman’s menstrual period, especially if the physician is using a liquid-based test; if bleeding is extremely heavy, endometrial cells can obscure cervical cells, and it is therefore inadvisable to have a Pap smear if bleeding is excessive.
The patient’s perception of the procedure ranges from no discomfort at all to severe discomfort (especially in women with cervical stenosis). Many women experience spotting or mild cramping afterward.
The physician or operator collecting a sample for the test inserts a speculum into the patient’s vagina, to allow access to the cervix. Samples are collected from the outer opening or Os of the cervix using an Aylesbury spatula and an endocervical brush, or (more frequently with the advent of liquid-based cytology) a plastic-fronded broom. The broom is not as good a collection device, since it is much less effective at collecting endocervical material than the spatula and brush. The cells are placed on a glass slide and checked for abnormalities in the laboratory.
The sample is stained using the Papanicolou technique, in which tinctorial dyes and acids are selectively retained by cells. Unstained cells cannot be visualized with light microscopy. The stains chosen by Papanicolou were selected to highlight cytoplasmic keratinization, which actually has almost nothing to do with the nuclear features used to make diagnoses now.
14.2 Whom to screen for Pap Smear Test
Guidelines on whom to screen vary from country to country. In general, screening starts at age 20 or 25 and continues until about age 50 or 60. There is probably no benefit screening women aged 60 or over whose previous tests have been negative.
There is little or no benefit to screening women who have not had sexual contact. HPV can be transmitted in sex between women, so women who have only had sex with other women should be screened, although they are at somewhat lower risk for cervical cancer.
Guidelines on frequency of screening vary – typically every one to three years for those who have not had previous abnormal smears. Women should wait no more than three years after the first time they have intercourse to start screening since most women contract HPV soon after becoming sexually active. It takes an average of a year, but can take up to four years, for a woman’s immune system to control the initial infection. Screening during this period may show this immune reaction and repair as mild abnormalities, which are usually not associated with cervical cancer, but could cause the woman stress and result in further tests and possible treatment. Cervical cancer usually takes time to develop, so delaying the start of screening a few years does not pose much risk of missing a potentially precancerous lesion.
Pap smear screening is still recommended for those who have been vaccinated against HPV, since the vaccines do not cover all of the HPV types that can cause cervical cancer. Also, the vaccine does not protect against HPV exposure before vaccination.
14.3. Other Prevention Measures for Cancer of Cervix
- Limiting the number of sexual partners
- Using a latex condom for intercourse
- Stopping smoking