Pap Test - Indications

Indications

Screening guidelines vary from country to country. In general, screening starts about the age of 20 or 25 and continues until about the age of 50 or 60. Screening is typically recommended every three to five years, as long as results are normal.

Women should wait a few years after they first have intercourse before they start screening, and should not be screened before age 21. American Congress of Obstetricians and Gynecologists (ACOG) and others recommend starting screening at age 21 (since that is a few years after initial sex for most American women). Many other countries wait until age 25 or later to start screening. For instance, some parts of Great Britain start screening at age 25.

Most women who contract HPV do so 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 poses little risk of missing a potentially precancerous lesion. For instance, screening women under age 25 does not decrease cancer rates under age 30.

There is little or no benefit to screening women who have not had sexual contact. For example, United States Preventive Services Task Force (USPSTF) recommends waiting at least three years after first sex. 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 three to five years for those who have not had previous abnormal smears. Some older recommendations suggested screening as frequently as every one to two years, however there is little evidence to support such frequent screening; annual screening has little benefit but leads to greatly increased cost and many unnecessary procedures and treatments. It has been acknowledged since before 1980 that most women can be screened less often. In some guidelines, frequency depends on age; for instance in Great Britain, screening is recommended every 3 years for women under 50, and every 5 years for those over.

Screening should stop about age 65 unless there is a recent abnormal tests or disease. There is probably no benefit screening women aged 60 or over whose previous tests have been negative. If a woman's last three Pap results were normal, she can stop at age 65, according to the USPSTF, ACOG, ACS and ASCP; England's NHS says 64. There is no need to continue screening after a complete hysterectomy for benign disease.

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.

More frequent Pap smears may be needed to follow-up after an abnormal Pap smear, or after treatment for abnormal Pap or biopsy results, or after treatment for cancer.