If you have an “abnormal” pap smear, what does it mean? What should you do?
Since the development of the pap test (or pap smear) in the 1940s, rates of cervical cancer have declined dramatically. According to the National Institutes of Health, cervical cancer is only the 14th most common cancer among women. Although cervical cancer is not occurring as frequently as it once did, women in the United States are still at risk for cervical cancer. Because of frequent and routine pap testing, cervical cell abnormalities can be identified and treated before those abnormalities go to cancer. Although the rates of cervical cancer are declining, there are many women who will have an “abnormal” pap smear in their lifetime. This month we will discuss how to understand an abnormal pap test result. Next month we will discuss the follow-up and management of abnormal pap test results.
The number one cause of cervical cancer in women is the human papillomavirus (HPV). There are many different types of HPV, and some are more likely to cause cancer than others. Over 70 percent of cases of cervical cancer are caused by type 16 or 18 of the human papillomavirus. HPV is a very common virus, and it has been estimated that 75 to 80 percent of sexually-active adults will come in contact with HPV by age 50.
However, not every woman who has HPV will go on to develop cervical cancer. Often the body’s immune system will clear the HPV infection. If HPV is not cleared and the infection is persistent, it is more likely that HPV will cause cellular changes to the cervix. There is a very wide range of cervical changes that can occur, and the average time it takes from initial infection to invasive cervical cancer is 15 years. There are some cases of this process occurring more rapidly; however, for the most part, it takes years for cervical cancer to develop.
Routine pap tests and HPV testing are designed to identify abnormalities in the cells of the cervix before they can go to cancer. This is why it is vital that all women have routine pap testing performed by their healthcare provider. Often there are no symptoms in early cases of cervical cancer, which is why it is important to get this screening test.
The pap test is performed during a pelvic examination in women age 21 and older. A flexible plastic brush sweeps the surface of the cervix, and these cells are placed in a transport medium and sent to a laboratory where the cells are examined under a microscope. A doctor (or pathologist) can determine if the cells are normal or abnormal.
When your healthcare provider goes over the results of your pap smear, there are a number of different findings that can be present. It will depend on your age and/or the result of the pap test if HPV testing is also performed. Because both an analysis of the cells and HPV typing may be performed, there is a wide range of results for a pap test.
When the pathologist examines the cervical cells, he or she will determine if the cells are normal or abnormal. A “normal” test result is straightforward—it means that no abnormalities were detected. An “abnormal” pap test will be classified based on what is seen under the microscope.
Squamous Intraepithelial Lesion (SIL) is a term that is used when describing abnormal cervical cell changes seen on pap tests. “Squamous” refers to the cell type that lines the outer cervix and the vagina. SIL may be low grade or high grade. Low-grade squamous intraepithelial lesion, or LSIL, is a milder abnormality of the cells, most often caused by HPV and will often go away on its own. High-grade squamous intraepithelial lesion, or HSIL, is a more serious abnormality that is more often associated with cancer and precancer.
There are three other classifications of abnormal pap results that are used to describe findings. Atypical cells of undetermined significance, or ASCUS, is somewhat of a borderline classification. This classification means that changes in the cervical cells were seen, but they cannot be classified as LSIL or HSIL. Sometimes HPV testing will be performed for an ASCUS result to give the provider more information to guide follow-up.
Atypical squamous cells, cannot exclude HSIL, or ASC-H, means that cervical cell changes are detected, and there is a concern that a high-grade lesion could be the cause. Atypical glandular cells, or AGC, is a finding of glandular cells in the pap sample. Glandular cells are found in the inner lining of the cervix, but they are also found in the endometrium, or inner lining of the uterus. An AGC finding could raise suspicion of endometrial cancer, especially if a woman has additional risk factors.
HPV testing may or may not be performed along with the pap test, depending on different factors. HPV co-testing (or HPV testing along with pap testing) is done routinely in women age 30 and older. Laboratories might also run HPV testing as a reflex test. This means that if certain criteria are met, such as an atypical finding on the pap test, then the HPV test will be added on, after the fact, to give the healthcare provider more information.
HPV test results are reported as positive or negative. If HPV is negative, then that means that the virus was not detected. A positive HPV result may be reported in a number of different ways, depending on the laboratory and the way the test was ordered. Sometimes more specific HPV typing will be performed to see if a high-risk type of HPV was detected. This is often testing for type 16 and 18.
All of this information will be taken into account when your healthcare provider is developing a plan for follow-up. If you have questions about your pap test or HPV result, it is always a good idea to discuss this with your provider. Next month we will discuss how abnormal pap tests are managed and treated.
Emily Nobles, WHNP, is a nurse practitioner at Atlantic Ob/Gyn located in Va. Beach and Chesapeake. For more information, call 757-463-1234 or visit www.atlanticobgyn.com.