Pap test
The Pap test, or Pap smear, is a screening procedure designed to detect abnormal cells in the cervix, helping to identify cases of cervical dysplasia that could lead to cervical cancer. Recommended primarily for women aged 21 to 65, the test is typically performed every three years, with specific guidelines regarding HPV testing and the continuation of screening based on individual health history. During the procedure, a healthcare provider collects cells from the cervix using a speculum, spatula, and cytobrush, which are then analyzed in a laboratory.
The introduction of the Pap test in the early 1940s has significantly reduced the incidence of invasive cervical cancer, although it remains a leading cause of cancer among women globally. While the primary purpose of the test is cancer screening, it can also reveal incidental findings such as infections. The procedure is generally safe, with minor risks like slight spotting afterward. Additionally, a related screening method, the anal Pap test, is used for high-risk populations to monitor anal dysplasia and cancer. Overall, the Pap test plays a crucial role in women's health and cancer prevention.
Pap test
Also known as: Pap sampling, Pap smear
Anatomy or system affected: Genitals, reproductive system, uterus
Definition: A sampling of cells from the cervix or vagina used to screen for dysplasia (precancer) and cancer
Indications and Procedures
Formerly, Pap testing was recommended for all women over the age of eighteen or for women who are sexually active. Revised guidelines were issued by the American Cancer Society, the American College of Obstetricians and Gynecologists, and the Preventive Services Task Force, part of the US Department of Health and Human Services. These updated guidelines generally stipulate that women between the ages of twenty-one and sixty-five have Pap screening every three years, with human papillomavirus (HPV) testing depending on age and previous results.
The guidelines also recommend less frequent Pap testing for women who have had three consecutive negative tests; the guidelines also call for a cutoff to Pap testing in older women without abnormalities. Pap testing guidelines for women who have had a hysterectomy (with sampling of the vaginal cuff) vary depending on whether the hysterectomy was done for benign or malignant causes. The guidelines recommend that only women who have had malignant disease continue Pap testing.
A Pap test is performed easily during an office visit. Generally, the patient lies on her back with legs flexed and knees apart, although alternative positions can be utilized for women with limited mobility or with disabilities. A speculum is then carefully inserted into the vagina, and the cervix is visualized. A spatula is used to gently scrape off cells from the transition zone of the cervix. A cytobrush samples cells from the cervical canal. These cells are then placed in a preservative and sent to a pathology laboratory for analysis. The term “Pap smear” derives from the fact that before the advent of liquid preservative methods of collecting samples, samples were “smeared” on a glass slide and then sent to a laboratory for analysis.
Uses and Complications
The main use of Pap testing is to identify asymptomatic cases of dysplasia (abnormal growth) of the cervix and vagina. With early treatment of dysplasia, the incidence of and number of deaths from cervical cancer have decreased dramatically. Although cancer screening is the primary purpose and use of Pap testing, incidental findings may include vaginal infections of bacteria, fungi, or parasites. In rare cases, Pap tests may also detect abnormal cells shed from the endometrium.
There are no serious risks from the procedure. Women may see a small amount of spotting after the procedure as a result of abrasions from the spatula or cytobrush.
Perspective and Prospects
The Pap test was introduced in 1943 by George N. Papanicolaou and Herbert F. Traut. Since then, the incidence of invasive cervical cancer has decreased dramatically, although cervical cancer remains the second most prevalent malignancy among women worldwide, according to the World Health Organization.
A screening test analogous to cervical Pap sampling, called the anal cytology, or "anal Pap test," has been developed to screen for anal dysplasia and cancer. It has been used primarily on high-risk patients, such as those with human immunodeficiency virus (HIV), women who have had cervical or vulvar cancer, and HIV-negative men who have sex with men.
Bibliography
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"Cervical Cancer: Screening." US Preventive Services Task Force, 21 Aug. 2018, www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/cervical-cancer-screening. Accessed 19 July 2023.
"Cervical Cancer Screening." National Cancer Institute, US Department of Health and Human Services, 27 Apr. 2023, www.cancer.gov/types/cervical/patient/cervical-screening-pdq. Accessed 19 July 2023.
Kumar, Vinay, et al., eds. Robbins Basic Pathology. 10th ed., Elsevier, 2018.
Lobo, Rogerio A., et al. Comprehensive Gynecology. 8th ed., Elsevier, 2022.
"Pap Test." MedlinePlus, US National Library of Medicine, medlineplus.gov/ency/article/003911.htm. Accessed 19 July 2023.