Cervical Cancer - Diagnosis

Classifying Cervical Cells and Determining Further Testing

The cells viewed in a cervical smear sample are classified on a scale representing the spectrum of cell changes from normal to cancerous. The smear is first characterized as either "normal" or "abnormal."

Once abnormal cells are identified, the doctor must decide whether the patient needs only repeat Pap smears, a test for the HPV virus, or colposcopy (a procedure used to magnify the cervix and permit detection of lesions for biopsy). To help the doctor make the decision, the abnormal cells are divided into categories, depending on the degree of abnormality. These classifications are based on the 2001 Bethesda System (TBS) which is formulated to standardize the reporting of Pap test results.

Atypical Squamous Cells (ASC). Atypical squamous cells (ASC) are mildly abnormal cells on the surface of the cervix. They may simply represent inflammation. Over 80% of these cells normalize, but unfortunately, between 5 - 17% of these women have a chance for having CIN II and III dysplasia (potentially invasive cells). Experts have now further categorized ASC as the following:

• ASCUS. This category identifies atypical squamous cells of undetermined significance. They are the lowest risk abnormal cells. Women with ASCUS should be tested for human papillomavirus infection (HPV). If results indicate they are infected with HPV, they should be given colposcopy, a more invasive diagnostic procedure to determine if the condition is actually at a more aggressive stage. If they do not have HPV they are simply monitored with repeat Pap smears.
• ASC-H. This category refers to the presence of atypical squamous cells, but a doctor cannot exclude possible high-grade squamous intraepithelial lesions. Such women have a 24 - 94% chance of having CIN II and III. All are referred for colposcopy.

Among those with ASC, immunosuppressed women and those with high-risk human papillomavirus infections are at higher risk for CIN II and III and should always be given colposcopy. Postmenopausal women with normal immune systems have a lower risk than younger women. It should be strongly noted, however, that actual risk for cervical cancer in general in women with ASC is only 0.1 - 0.2%.

Low Grade Squamous Intraepithelial Lesions (LSIL). Low-grade squamous intraepithelial lesions (LSIL) are typically associated with human papillomavirus changes, with or without early dysplasia (CIN I). Between 15 - 30% of women with LGIL, however, may have CIN II or III on biopsy. Women with LSIL are either monitored with repeat Pap smears or given colposcopy. Experts recommending colposcopy argue that these are high-risk women and there is a risk for delaying a diagnosis of cancer using only repeat Pap smears.

High-Grade Squamous Intraepithelial Lesions (HSIL). High-grade squamous intraepithelial lesions (HSIL) are associated with moderate dysplasia and other CIN II or III. Such women are always referred to colposcopy for biopsy. Even if colposcopy results report only CIN I, over a third of these women are likely to have CIN II or III. Experts, therefore, recommend a careful review of the tests in such cases. Pregnancy poses a problem since it increases the chance in HSIL for both normal and abnormal results. In nonpregnant women, particularly when fertility is not an issue, immediate treatment with loop electrosurgical excision procedure (LEEP) may be appropriate.

Atypical Glandular Cells (AGS). Atypical glandular cells are uncommon, but pose a higher risk for cancerous changes than ASC or LSIL. Between 9 - 54% have some CIN, between 0 - 8% have carcinoma in situ, and between 1 - 9% have invasive cancer. Experts recommend that the next step should be a colposcopy (rather than a repeat Pap smear).