Screening for cervical cancer
Cervical Cancer Screening is testing of all women at risk of cervical cancer, most of whom will be without symptoms.
Cervical Cancer Screening aims to detect precancerous changes, which, if not treated, may lead to cancer.
Cervical Cancer Screening is only effective if there is a well organized system for follow-up and treatment.
Women who are found to have abnormalities on cervical cancer screening need follow-up, diagnosis and possibly treatment, in order to prevent the development of cancer or to treat cancer at an early stage.
Several tests can be used in screening for cervical cancer. The Pap smear (cytology) is the only test that has been used in large populations and that has been shown to reduce cervical cancer incidence and mortality. Other tests (VIA, VILI, HPV) show promise but there is as yet no comparable evidence on their effectiveness. Large studies are still under way.
Regardless of the test used, the key to an effective programme is to reach the largest proportion of women at risk with quality cervical cancer screening and treatment.
Organized cervical cancer screening programmes designed and managed at the central level to reach most women at risk are preferable to opportunistic screening.
PAP TEST / PAP SMEAR:
A Pap test is a procedure to collect cells from the surface of the cervix and vagina. A piece of cotton, a brush, or a small wooden stick is used to gently scrape cells from the cervix and vagina. The cells are viewed under a microscope to find out if they are abnormal. This procedure is also called a Pap smear. A new method of collecting and viewing cells has been developed, in which the cells are placed into a liquid before being placed on a slide. It is not known if the new method will work better than the standard method to reduce the number of deaths from cervical cancer.
VISUAL INSPECTION WITH ACETIC ACID (VIA):
VIA involves inserting a vaginal speculum and swabbing the cervix with 3% to 5% acetic acid solution (ordinary table vinegar) before doing a cervical inspection. Normal squamous epithelium is light pink in color and the columnar epithelium is red. CIN lesions will turn white for a few minutes after application of acetic acid. The effect of acetic acid is thought to depend on the amount of nuclear proteins and cytokeratins present in the cervical epithelium, which increases in CIN. The health care provider doing the test identifies one of the three categories for results: the test is positive with an acetowhite area present (VIA-positive), negative with no acetowhite areas (VIA-negative), or suspicious for cervical cancer. Careful training is needed to minimize the rate of false-positive results. A high false-positive rate with VIA could lead to overtreatment and unnecessary referral of women free of actual cervical abnormalities. Nurses, midwives, or other health care providers can perform the procedure, if they have adequate training, which usually takes 1 to 2 weeks. The procedure itself does not require sophisticated equipment, it is low in cost, and results are immediately available, making treatment at the same visit a possibility. All required supplies and equipment are readily available in all geographic settings. Like cytology, VIA may be less effective for older women in their 50s or 60s because of the tendency of the transformation zone and any lesions within it to recede into the endocervical canal.
HUMAN PAPILLOMAVIRUS TEST
The human papillomavirus (HPV) test detects the presence of the human papillomavirus, a virus that can lead to the development of genital warts, abnormal cervical cells or cervical cancer.
Your doctor might recommend the HPV test if:
- Your Pap test was abnormal, showing atypical squamous cells of undetermined significance (ASCUS)
- You’re age 30 or older
The HPV test is available only to women; no HPV test yet exists to detect the virus in men. However, men can be infected with HPV and pass the virus along to their sex partners.
Why Its Done?
The HPV test is a screening test for cervical cancer, but the test doesn’t tell you whether you have cancer. Instead, the test detects the presence of HPV, the virus that causes cervical cancer, in your system. Certain types of HPV — including types 16 and 18 — increase your cervical cancer risk.
Knowing whether you have a type of HPV that puts you at high risk of cervical cancer means that you and your doctor can better decide on the next steps in your health care. Those steps might include follow-up monitoring, further testing, or treatment of abnormal or precancerous cells.
Routine use of the HPV test in women under age 30 isn’t recommended, nor is it very helpful. HPV spreads through sexual contact and is very common in young women, so, frequently, the test results will be positive. However, HPV infections often clear on their own within a year or two. Cervical changes that lead to cancer take several years — often 10 years or more — to develop. For these reasons, you might follow a course of watchful waiting instead of undergoing treatment for cervical changes resulting from an HPV infection.