Abnormal Pap Smears
It is scary to hear that your Pap test results are "abnormal." But abnormal Pap test results
usually do not mean you have cancer. Most often there is a small problem with the
Some abnormal cells will turn into cancer. But most of the time, these unhealthy cells will go away on their own. By treating these unhealthy cells, almost all cases of cervical cancer can be prevented. If you have abnormal results, to talk with your doctor about what they mean.
Different Levels of Abnormal Paps
Most laboratories in the United States use a standard set of terms called the Bethesda System
report test results. Under the Bethesda System, Pap test samples that have no cell
are reported as "negative for intraepithelial lesion or malignancy." Samples with cell
abnormalities are divided into the following categories:
- ASC - atypical squamous cells. Squamous cells are the thin flat cells that form the surface of the cervix. The Bethesda System divides this category into two groups:
- ASC–US - atypical squamous cells of undetermined significance. The squamous cells do not appear completely normal, but doctors are uncertain about what the cell changes mean. Sometimes the changes are related to human papillomavirus (HPV) infection (see Question 13). ACS–US are considered mild abnormalities.
- ASC–H - atypical squamous cells cannot exclude a high-grade squamous intraepithelial lesion. The cells do not appear normal, but doctors are uncertain about what the cell changes mean. ASC–H may be at higher risk of being precancerous.
- LSIL - low-grade squamous intraepithelial lesion. Low-grade means there are early changes in the size and shape of cells. The word lesion refers to an area of abnormal tissue. Intraepithelial refers to the layer of cells that forms the surface of the cervix. LSILs are considered mild abnormalities caused by HPV infection.
- HSIL - high-grade squamous intraepithelial lesion. High-grade means that there are more marked changes in the size and shape of the abnormal (precancerous) cells, meaning that the cells look very different from normal cells. HSILs are more severe abnormalities and have a higher likelihood of progressing to invasive cancer.
What do abnormal results mean?
A physician may simply describe Pap test results to a patient as "abnormal." Cells on the
of the cervix sometimes appear abnormal but are very rarely cancerous. It is important to
remember that abnormal conditions do not always become cancerous, and some conditions are
likely to lead to cancer than others. A woman may want to ask her doctor for specific
information about her Pap test result and what the result means.
There are several terms that may be used to describe abnormal results.
- Dysplasia is a term used to describe abnormal cells. Dysplasia is not cancer, although it may develop into very early cancer of the cervix. The cells look abnormal under the microscope, but they do not invade nearby healthy tissue. There are four degrees of dysplasia, classified as mild, moderate, severe, or carcinoma in situ, depending on how abnormal the cells appear under the microscope. Carcinoma in situ means that abnormal cells are present only in the layer of cells on the surface of the cervix. However, these abnormal cells may become cancer and spread into nearby healthy tissue.
- Squamous intraepithelial lesion (SIL) is another term that is used to describe abnormal changes in the cells on the surface of the cervix. The word squamous describes thin, flat cells that form the outer surface of the cervix. The word lesion refers to abnormal tissue. An intraepithelial lesion means that the abnormal cells are present only in the layer of cells on the surface of the cervix. A doctor may describe SIL as being low-grade (early changes in the size, shape, and number of cells) or high-grade (precancerous cells that look very different from normal cells).
- Cervical intraepithelial neoplasia (CIN) is another term that is sometimes used to describe abnormal tissue findings. Neoplasia means an abnormal growth of cells. Intraepithelial refers to the layer of cells that form the surface of the cervix. The term CIN, along with a number (1 to 3), describes how much of the thickness of the lining of the cervix contains abnormal cells.
- Atypical squamous cells are findings that are unclear, and not a definite abnormality.
Cervical cancer, or invasive cervical cancer, occurs when abnormal cells spread deeper into the cervix or to other tissues or organs.
What to do if Pap test was "abnormal"
There are many reasons for "abnormal" Pap test results. If results of the Pap test are
show a small change in the cells of the cervix, your doctor will probably repeat the Pap
If the test finds more serious changes in the cells of the cervix, the doctor will suggest more powerful tests. Results of these tests will help your doctor decide on the best treatment. These include:
- Colposcopy: The doctor uses a tool called a colposcope to see the cells of the vagina and cervix in detail.
- Endocervical curettage: The doctor takes a sample of cells from the endocervical canal with a small spoon-shaped tool called a curette.
- Biopsy: The doctor removes a small sample of cervical tissue. The sample is sent to a lab to be studied under a microscope.
How are human papillomaviruses associated with the development of cervical cancer?
Human papillomaviruses (HPVs) are a group of more than 100 viruses. Some types of HPV cause
common warts that grow on hands and feet. Over 30 types of HPV can be passed from one person
another through sexual contact. Some of these sexually transmitted HPVs cause wart-like
on the genitals but do not lead to cancer. About 15 sexually transmitted HPVs are referred
"high-risk" because they are more likely to lead to the development of cancer.
HPV infection is the primary risk factor for cervical cancer. About 6 million new genital HPV infections occur each year in the United States. However, although HPV infection is very common, only a very small percentage of women with untreated HPV infections develop cervical cancer.
Do women who have been vaccinated against HPVs still need to have Pap tests?
Yes. Pap tests continue to be essential to detect cervical cancers and precancerous changes,
in women who have been vaccinated against HPVs.
The U.S. Food and Drug Administration (FDA) recently approved Gardasil®, a vaccine that is highly effective in preventing infection with four types of HPV. These vaccines do not protect against all HPV types that cause cervical cancer. In addition, they do not protect or treat women who are already infected with HPV. Therefore, it is important for vaccinated women to continue to undergo cervical cancer screening as is recommended for women who have not been vaccinated.