Cervical cancer screening is an essential part of a woman’s routine health care. Nearly all cases of cervical cancer are caused by infection with sexually transmitted oncogenic, or high-risk, types of human papillomavirus, or HPV 16 and 18. The primary goal of screening is to identify precancerous lesions caused by HPV so they can be removed to prevent invasive cancers from developing. A secondary goal is to find cervical cancers at an early stage, when they can usually be treated successfully. Routine cervical screening has been shown to greatly reduce both the number of cervical cancer cases and deaths from the disease.
Screening Methods
There are several methods for cervical screening for prevention. These can be used alone or in combination:
- VIA looks for suspicious precancerous lesions. The cervix is swabbed with vinegar, which causes any precancerous lesions to turn white.
- Pap smears take cell samples from a woman’s cervix to assess for abnormal cells.
- The HPV DNA test looks for the presence of high-risk HPV strains that cause cancer. Women found positive are further screened with VIA or a pap smear to look for precancerous lesions or abnormal cells. Facilities without HPV DNA testing may simply offer Visual Inspection with Acetic Acid (VIA) or Pap smears for screening.
Precancers can be detected and removed with preventive therapy before it develops into cancer through simple outpatient procedures.
Types of preventive therapy for precancerous lesions include cryotherapy, thermocoagulation, Loop Electrosurgical Excision Procedure (LEEP), and conization.
Preventive therapy may be performed immediately after screening or could require referral to another facility with these services.
Remember: Precancer is not actually cancer. Precancer refers to early abnormal cellular changes that may develop into cancer if not treated with preventive therapy. Health care providers remove these cells to prevent them from developing into cancer.
How is cervical cancer screening done?
Cervical cancer screening can be done in a medical office, a clinic, or a community health center. It is often done during a pelvic examination.
While a woman lies on an exam table, a health care professional inserts an instrument called a speculum into her vagina to widen it so that the upper portion of the vagina and the cervix can be seen. This procedure also allows the health care professional to take a sample of cervical cells. The cells are taken with a wooden or plastic scraper and/or a cervical brush and placed in a vial of liquid preservative. The slide or vial is then sent to a laboratory where the cells are tested for the presence of high-risk types of HPV and/or examined under a microscope with an automated liquid-based Pap cytology test. When both tests are done using the same sample, this is referred to as “cotesting.”
Researchers have found that screening may be less effective for obese women, possibly because of challenges in visualizing the cervix and obtaining a cell sample. Approaches to improve cervical visualization in obese women, including the use of larger speculum, may be helpful.
When should a woman begin cervical cancer screening, and how often should she be screened?
Women should talk with their doctor about when to start screening and how often to be screened. The screening guidelines are as follows:
- Women ages 21 through 29 should be screened with a Pap test every 3 years
- Women ages 30 through 65 should be screened with any of three tests:
- every 5 years with high-risk HPV testing alone
- every 5 years with Pap and high-risk HPV cotesting
- every 3 years with a Pap test alone
- Women with certain risk factors may need to have more frequent screening or to continue screening beyond age 65. These risk factors include:
- being infected with the human immunodeficiency virus (HIV)
- being immunosuppressed
- having been treated for a precancerous cervical lesion or cervical cancer
Screening for cervical cancer is not recommended for:
- women younger than 21 years
- women older than 65 years who have had adequate prior screening, with normal results, and who are not otherwise at high risk for cervical cancer
- women who have had a total hysterectomy (surgery to remove the uterus and cervix) and have no history of high-grade cervical lesions or cervical cancer
