By Ama Afrah
Screening and Prevention of cervical cancer
Until 1940, cervical cancer was the leading cause of death until the introduction of PAP TEST. Cervical cancer has become a preventable cancer since the discovery of the Human Papillomavirus (HPV) as the cause of almost all cases of cervical cancer. Vaccines for HPV was first approved in 2006 after discovery of the virus.
Pap test which has been approved as the most specific of all cervical cancer screening tests, involves looking at a sample of cells from the cervix under a microscope to see if there are any that are abnormal. It is a good test for finding not only cancer, but also finding cells that might become cancerous in the future. Other advantages of the Pap Test is that other infections apart from HPV can be picked up; Chlamydia, Herpes simplex virus, bacteria, parasitic infections (genital schistosomiasis), yeast or Candida infection as well as a woman’s hormonal status since the cells that makes up the ecto-cervix and vagina mature under influence of female hormones (estrogen, progesterone).
PAP test is part of a routine pelvic exam at recommended intervals.
Pap test is most reliable than colposcopy; there are more false positives and false negative associated with colposcopy.
RECOMMEND GUIDELINES OF SCREENING FOR WOMEN BETWEEN AGES 21-65:
• Women should not be screened before age 21 (if sexual debut was10 years, you are to start before age 21 years).
• Women 21 to 29 should be screened with the Pap test alone (conventional or liquid-based) every three years. HPV testing should NOT be used for screening in this age group.
• For women 30 and over, the preferred approach is the Pap test plus HPV testing (“co-testing”) every five years. Continued screening with the Pap test alone (without HPV testing) every three years is an acceptable alternative. While screening with HPV testing alone is promising, at this time it is not recommended for most clinical settings.
• Screening is not recommended for women over age 65 who have had at least three consecutive negative Pap tests or at least two negative HPV tests the last 10 years, with the most recent test in the last 5 years. Women in this age group who have a history of cervical pre-cancer (CIN2 or a more severe diagnosis) should continue routine screening for at least 20 years, even if this extends beyond age 65.
• Women who have undergone a hysterectomy (with removal of the cervix) for reasons not related to cervical cancer or pre-cancer should not be screened anymore.
• Women who have been vaccinated against HPV should follow the age-specific recommendations in these guidelines (for unvaccinated women). Currently, there are no alternative screening recommendations for women vaccinated against HPV.
The new guidelines are not intended for women with a history of cervical cancer, exposure to DES during a pregnancy, or women who are immunosuppressed (e.g. HIV positive).
It is important for women to know if a Pap test was performed because it is possible to have a pelvic exam without a Pap test. It is also important that women know and understand their Pap test results and follow through with any recommendations made by their healthcare provider.
Some abnormal Pap tests will be followed by colposcopy (examination of the cervix using a magnifying device to see the cervix more clearly) and biopsy of any abnormal appearing areas on the cervix. Any pre-cancerous areas can then be seen and, if needed, treated by a woman’s healthcare provider.
Current cervical cancer screening guidelines state that women with a slightly abnormal Pap test result (called “ASC-US”) and a negative HPV test can be screened again with co-testing in 3 years, or with the Pap test alone in 3 years. Women with a negative Pap result but a positive HPV test can either be rescreened with co-testing in one year, or tested with a test that can determine specific types of HPV (HPV16 and HPV 18).
FDA approved the HPV DNA test for women 25 and older for use alone to help a healthcare professional assess the need for a woman to undergo additional diagnostic testing for cervical cancer. The test also can provide information about the patient’s risk for developing cervical cancer in the future.
Using a sample of cervical cells, the cobas HPV Test detects DNA from 14 high-risk HPV types. The test specifically identifies HPV 16 and HPV 18 for now.
Screening for cervical cancer, whether with the Pap test or HPV test, remains a critical prevention step. However, the FDA approval in 2006 of the first vaccine to prevent cervical cancer represents the opportunity to eradicate this cancer. Now there are three vaccines, all given in a series of three injections into the muscle tissue over a 6 month period.
Cervarix targets two HPV types, 16 and 18, and is approved for females ages 9-25. These two high-risk HPV types cause about 70 percent of cervical cancers an even higher percentage of some women.