The Meaning of an Abnormal Pap Smear

A normal Pap smear result is clear and reassuring. But an abnormal Pap smear result can seem far less definitive—and even worrisome.

Does an abnormal Pap mean cancer? Is it something to be concerned about in every case?

The answer lies in the details of your lab report. In addition to listing an abnormal result, it will provide information about the nature of the abnormal cells that were found. Each means something different about your health and what the next best steps for you may be.

Read on to learn about each of the possibilities so you can put your abnormal Pap smear results into perspective and make informed decisions about follow-up care.

ASCUS

ASCUS stands for atypical squamous cells of undetermined significance. In other words, there are squamous cells (cells that cover the surface of the cervix) that don't look normal. However, those cells are not abnormal enough to be considered dysplasia.

ASCUS is the most common abnormal Pap smear result. It is usually nothing to worry about. Although ASCUS can be caused by an early human papillomavirus (HPV) infection, an ASCUS diagnosis may also be due to irritation from sex or even bad Pap smear technique. Diagnoses of ASCUS will often resolve spontaneously over time with no intervention or treatment.

Follow-up for ASCUS is usually a repeat Pap smear at six months. If that's normal, then no further follow-up is necessary. At that point, a patient can return to the normal screening schedule.

Alternatively, patients diagnosed with ASCUS may be tested for HPV. Then, anyone who is positive for a high-risk type would be sent for further follow-ups, such as colposcopy or loop electrosurgical excision procedure (LEEP).

SIL

Squamous intraepithelial lesion (SIL) is another common abnormal Pap smear result. Squamous intraepithelial lesions are squamous cells that have been changed in a way that suggests they may eventually become cancerous.

This, however, does not mean they will become cancerous. Even without treatment, many cases of SIL will resolve on their own.

Squamous intraepithelial lesion diagnoses can be divided into two types: high grade and low grade. These correlate to cervical intraepithelial neoplasia (CIN) diagnoses of CIN 1 and CIN 2 or 3, respectively.

LSIL/CIN 1: Low grade squamous intraepithelial lesions (LSIL) are almost always a sign that a woman has been infected with HPV. This diagnosis also implies that the healthcare provider reading the Pap smear or biopsy has seen signs that look like early-stage pre-cancer.

LSIL diagnoses are relatively common. They often resolve on their own without treatment.

In very young women, follow-up is usually a repeat Pap smear in six or 12 months. For older, reproductive-age women, the American Colleges of Obstetricians and Gynecologists (ACOG) guidelines suggest colposcopy to determine the extent of the damage. They do not necessarily recommend treatment. For post-menopausal women, follow-up may be a repeat Pap smear, HPV test, or colposcopy.

Because LSIL does so often heal on its own, most healthcare providers advocate a less aggressive approach to follow-up rather than treatment. In fact, the ACOG guidelines state that CIN 1/LSIL should not be treated unless it has persisted for more than two years, progresses to CIN 2 or CIN 3, or other medical factors are involved.

Over-treatment, however, is still relatively common. Sometimes when people hear the phrase "pre-cancerous cells" they decide they'd rather be safe than sorry, even when the treatment can have significant side effects.

HSIL/CIN 2-3: High grade squamous intraepithelial lesions (HSIL) are more likely to become cervical cancer than LSIL. However, many of these lesions still regress on their own.

Carcinoma in situ (CIS) is the most serious form of HSIL and the one most likely to progress to cancer. CIS may also be diagnosed as CIN 3.

During the colposcopy procedure, lesions may be biopsied, or they may be treated by LEEP, conization, freezing (cryotherapy), or laser therapy. For small enough lesions, a punch biopsy may actually be used as treatment.

ASC-H

ASC-H stands for atypical squamous cells, cannot exclude HSIL. It basically means that the healthcare providers are having trouble making a diagnosis.

You might have HSIL, you might not. The practitioners can't tell without additional testing. Follow-up by colposcopy is recommended.

AGC

Atypical glandular cells (AGC) refers to changes to the cervix that do not occur in the squamous epithelium. Instead, abnormal glandular cells were seen in the sample. This result suggests there may be cancer in the upper parts of the cervix or the uterus.

Follow-up for AGC can include colposcopy, HPV testing, and sampling of the lining of both the cervix (the endocervix) and uterus (the endometrium). The choice depends on what specific types of abnormal cells were seen in the smear.

Treatment for AGC, if necessary, is more invasive than treatment for squamous cell lesions.

Cancer

If you have been diagnosed with cervical cancer, it means that the damage to your cervix is no longer superficial. You will probably be sent to an oncologist for further follow-up and treatment. The extent of treatment will vary by the severity of your cancer.