Cervical Cancer

Laboratory Tests

Screening tests

Pap smear
The conventional Papanicolaou (Pap) smear, in which cervical cells are collected, smeared on a glass slide, and specially stained for microscopic examination, is widely used to screen for precancerous or cancerous changes in cervical cells. More recently, a liquid-based technique has been introduced and is currently the method of choice. While either technique is acceptable, the liquid-based process eliminates unwanted slide-drying artifacts as well as interfering substances such as lubricant, contaminating menstrual blood, or any discharge. The latest technology provides an even greater comprehensive review using computerized slide analysis systems that screen a greater number of cells on a slide looking for any abnormalities. These changes to the traditional Pap test are aimed at improving the detection of a small number of abnormal cervical cells that may be present early on in the disease process.

The guidelines from various organizations for intervals for cervical cancer screening with a Pap smear differ somewhat:

• The American College of Obstetricians and Gynecologists (ACOG) recommends that women younger than 21 years old not be screened because of the very low risk of cervical cancer. Routine screening may lead to unnecessary and harmful overtreatment due to normal changes that commonly occur in this age group. Women between the ages of 21-29 should be screened with a Pap smear every two years.
• The American Cancer Society and the U.S. Preventive Services Task Force recommend that women should begin getting Pap smears about 3 years after becoming sexually active, but no later than 21 years of age. They should get tested annually until age 30.
• The guidelines for all three organizations for women 30 years of age and older are the same: those who have no new risk factors and have had normal Pap smears 3 years in a row should be tested every 3 years. However, if any risk factors exist, such as exposure to DES (diethylstilbestrol), previous diagnosis of cervical cancer, high-risk sexual behavior, HIV infection, or a compromised immune system, then testing should occur more frequently than every 3 years.
• ACOG recommends discontinuing Pap smears between the ages of 65 and 70 if there have been no abnormal Pap smears for 3 years and no other abnormal test results for 10 years. However, screening may still be appropriate if any risk factors, such as those listed above, are present.

HPV test
HPV testing and typing is available. The American College of Obstetricians and Gynecologists (ACOG) released guidelines in August 2003 recommending that women 30 years or older be offered an HPV DNA test in addition to their Pap smear and pelvic exam as an additional screening tool for cervical cancer. (It was not recommended for screening those under 30 because there is an increased prevalence of HPV in this age group, but it rarely causes cancer). The HPV DNA test detects the presence of the most common high-risk HPV types, although it does not determine the specific type. According to ACOG, if both the HPV DNA test and Pap smear are negative and the woman does not have an underlying health condition, such as HIV or immunosuppression, then the patient can wait for three years before having another Pap smear and HPV DNA test (but should continue to have their annual pelvic exam).

The HPV DNA test and Pap smear may be ordered on a more frequent basis to monitor positive HPV tests, abnormal Pap smear changes, and those patients who have underlying medical conditions, such as HIV or immunosuppression.

It is not usually necessary to determine the specific type or strain of HPV present but, if it is required, other DNA testing methods may be used. Determining the presence and specific strain of HPV in women who have abnormal Pap smears may offer doctors additional information about their patients’ risk of developing cervical cancer. Although studies have shown that persistent infection with certain high-risk strains of HPV are the cause of most cases of cervical cancer, most women who are infected with HPV do not develop cervical cancer, and a few women who do have cervical cancer do not have HPV. Additional research in this area is needed to show whether HPV testing may be most useful as either an adjunct test to or replacement for the Pap smear.

Diagnostic tests

• Colposcopy - a follow-up test that involves putting a vinegar-like solution on the cervix and then using a bright light and magnifying instrument to look closely at the cervix, checking for abnormal areas. A Schiller test may also be done in which iodine is placed on the cervix, causing normal cells to turn brown and abnormal cells to show up as white or yellow.
• Biopsy - if abnormal areas are found on the cervix, small pieces of tissue will be removed for examination by a pathologist. A biopsy and microscopic evaluation is the only way to tell for sure whether abnormal cells are cancerous, precancerous, or reactive for some other reason.