Cervical Cancer

Pap tests are recommended for all women 18-70 years of age who have ever had sex and have not  had a hysterectomy (i.e. an intact uterus and cervix) (A). Pap tests should be performed every 2 years and should commence between 18-20 years of age, or 1-2 years after sexual activity commences, whichever is later (B). Women over 70 years of age who request a Pap test or who have never had a Pap test should be screened. Screening should be ceased for this group only after two successive negative tests. Preventive Services Task Force (USPSTF) strongly recommends screening for cervical cancer in women who have been sexually active and have a cervix. (A) The USPSTF recommends against routinely screening women older than age 65 for cervical cancer if they have had adequate recent screening with normal Pap smears and are not otherwise at high risk for cervical cancer (go to Clinical Considerations). (D)

Risk of Cervical Cancer

Pap Test Technique

An optimal Pap test sample contains sufficient mature and metaplastic squamous cells to indicate optimal sample from the transformation zone, and sufficient endocervical cells to indicate that the upper limit of the transformation zone was sampled, and to provide a sample for screening for adenocarcinoma and its precursors. It is preferable to avoid taking the smear during menstruation, if obvious vaginal infection is present, or within 24 hours of vaginal cream or pessary use. The appropriate sampling instrument to be used depends on the position of the transformation zone.

In some women, the squamo-columnar junction is within the endocervical canal – for these a cytobrush and spatula should be used. Cytobrushes should not be used in pregnant women. Cervical cells should be spread onto a glass slide and immediately fixed with spray or in alcohol. If the slide test is technically unsatisfactory, it should be repeated within 6–12 weeks. It is important to ensure that the patient obtains the result of her test. If the report shows:

• For low grade LSIL (definite or possible) the woman should have a repeat test in 12 months. There is insufficient evidence to support the use of HPV testing in triage LSIL. If the woman is over 30 years of age with no history of a negative test in the past 2–3 years, offer immediate colposcopy or repeat Pap test within 6 months
• If the test at 12 months shows LSIL (definite or possible) the woman should be referred for colposcopy. If any repeat test shows high grade changes, if the woman is symptomatic, or if she has a clinically abnormal cervix or is unduly anxious about the situation, earlier referral for colposcopy is recommended
• For high grade squamous lesions, the woman should be referred for colposcopic assessment and targeted biopsy where indicated
• For glandular abnormality or adenocarcinoma, refer for colposcopy by an experienced gynaecologist or oncologist

Clinical Considerations

• The goal of cytologic screening is to sample the transformation zone, the area where physiologic transformation from columnar endocervical epithelium to squamous (ectocervical) epithelium takes place and where dysplasia and cancer arise. A meta-analysis of randomized trials supports the combined use of an extended tip spatula to sample the ectocervix and a cytobrush to sample the endocervix.
• The optimal age to begin screening is unknown. Data on natural history of HPV infection and the incidence of high-grade lesions and cervical cancer suggest that screening can safely be delayed until 1-2 years after onset of sexual activity or until age 20, whichever comes first.
• Discontinuation of cervical cancer screening in older women is appropriate, provided women have had adequate recent screening with normal Pap results. The optimal age to discontinue screening is not clear, but risk of cervical cancer and yield of screening decline steadily through middle age. It was found evidence that yield of screening was low in previously screened women after age 65.
• Screening is recommended in older women who have not been previously screened, when information about previous screening is unavailable, or when screening is unlikely to have occurred in the past
• Evidence is limited to define "adequate recent screening." The guidelines recommend that older women who have had three or more documented, consecutive, technically satisfactory normal/negative cervical cytology tests, and who have had no abnormal/positive cytology tests within the last 10 years, can safely stop screening.
• It was found no direct evidence that annual screening achieves better outcomes than screening every 3 years. The majority of cervical cancers in the United States occur in women who have never been screened or who have not been screened within the past 5 years; additional cases occur in women who do not receive appropriate follow up after an abnormal Pap smear. Because sensitivity of a single Pap test for high-grade lesions may only be 60-80 percent, however, most organizations recommend that annual Pap smears be performed until a specified number (usually two or three) are cytologically normal before lengthening the screening interval.
• A majority of cases of invasive cervical cancer occur in women who are not adequately screened. Clinicians, hospitals, and health plans should develop systems to identify and screen the subgroup of women who have had no screening or who have had inadequate past screening.
• Newer Food and Drug Administration (FDA)-approved technologies, such as the liquid-based cytology (e.g., ThinPrep®), may have improved sensitivity over conventional Pap smear screening, but at a considerably higher cost and possibly with lower specificity. Even if sensitivity is improved, modeling studies suggest these methods are not likely to be cost-effective unless used with screening intervals of 3 years or longer. Liquid-based cytology permits testing of specimens for HPV, which may be useful in guiding management of women whose Pap smear reveals atypical squamous cells. HPV DNA testing for primary cervical cancer screening has not been approved by the FDA and its role in screening remains uncertain.
   

Created by: Dr Farouq Al-Zurba