What an LSIL Pap Smear Result Means

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A low-grade squamous intraepithelial lesion, commonly known as LSIL or LGSIL, is detected through a routine Pap smear. This shows that mild cervical dysplasia is present.

In cervical dysplasia, cells on the cervix (the lower portion of the uterus) are showing changes that are mildly abnormal, meaning the cells could turn into cervical cancer years down the line. The fact that they are considered "low-grade" means that the process is likely to be gradual if it happens at all.

Cervical dysplasia is not cancer or even pre-cancer. The term is simply used to describe abnormalities in cervical cells that suggest an increased risk of cancer.

According to a retrospective study from Brigham and Women’s Hospital in Boston, of the 1,076 people diagnosed with LSIL, 93 (8.3%) went on to develop cervical intraepithelial neoplasia (CIN), a precancerous condition.

A doctor holding a pap smear
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Cause

LSIL is almost always caused by human papillomavirus (HPV), the primary risk factor for cervical cancer. HPV is easily transmitted through vaginal, anal, or oral sex.

The good news is that the majority of people infected with HPV clear the virus spontaneously. For women whose immune systems are unable to clear the virus, cervical cancer may occur.

LSIL is only one of the possible interpretations of a Pap smear. If the cells are diagnosed as HGSIL (high-grade squamous intraepithelial lesion), it means that they have a greater likelihood of turning into cancer faster.

Detection

Guidelines for cervical cancer screening are changing, and when you visit your doctor for a checkup, you may receive a Pap smear (cytology), a primary HPV test alone, or both a Pap smear and an HPV test (cotesting).

According to 2020 American Cancer Society guidelines, the method of choice is primary HPV testing, yet this is not yet available everywhere.

A Pap smear is a procedure that tests for cervical cancer and takes just a few minutes. This procedure involves collecting cells from the cervix, which is the lower, narrow end of the uterus that's at the top of the vagina.

During a Pap smear, the person lies on an exam table and places their feet in stirrups. The doctor then inserts a medical instrument called a speculum (which is lubricated) into the vagina and uses a brush or swab to gently swipe the surface of the cervix to obtain a collection of cells. These cells are then sent to a lab to be analyzed.

HPV testing is performed in a similar manner and may be done at the same time as the Pap smear. While a number of HPV tests are available, only two are approved as a primary screening tool for cervical cancer.

These tests screen for the strains of HPV that can lead to cervical cancer (high-risk strains) including HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68. It is hoped that when HPV tests (approved ones) become widely available without barriers, these will replace cytology as a screening tool.

Screening Recommendations

In 2020, the American Cancer Society updated screening guidelines for cervical cancer in people at average risk for the disease. These apply to people who have a cervix:

  • An initial primary HPV test or combination of an HPV test and Pap smear (cotesting) should be done at age 25 (previously this was age 21).
  • If results are normal, people aged 25 to 65 should have either an HPV test or cotesting every five years until age 65. If only cytology (Pap smears) are available, the procedure should be repeated every three years.
  • At age 65, screening may be discontinued for women who have not had an abnormal test classified as CIN2 or more within the last 25 years, and have had negative screening tests over the preceding 10 years.

If LSIL Is Diagnosed

If you receive a diagnosis of LSIL, it's important to follow up with your doctor, as their recommendations on how to manage the results will differ among women depending on their age, history of prior Pap smears, results of an HPV test, and the presence of risk factors such as HIV or the use of immunosuppressant medications.

These risk factors are all considered as a physician estimates the risk that precancerous or cancerous changes could be present. Overall, there is a moderate risk that a Pap smear read as LSIL will progress to high-grade squamous intraepithelial lesions (HSIL) on follow-up or that HSIL will be present on biopsy.

In contrast, roughly half of Pap smears read as LSIL will regress (return to normal). The highest rates of HSIL are seen in people who have HPV tests positive for HPV 16 or 18.

HPV Test

If only a Pap smear was done, the first step may be performing an HPV test. An HPV test looks for the presence of certain strains of HPV associated with cervical cancer. Your doctor can usually obtain an HPV test on the same cells that were used on your initial Pap smear (the Pap smear that came back as "abnormal" because of LSIL).

If an HPV test is negative, and other risk factors are low, a physician may recommend repeating an HPV test or cotesting in one year. This is particularly true for people who are under the age of 25.

Colposcopy

colposcopy may be recommended for some people diagnosed with LSIL, including those who have a positive HPV test (especially if positive for HPV16 or HPV18), those didn't have HPV testing done, and some people who have a negative HPV test but are considered high risk based on screening history or other reasons.

For example, people with LSIL who are immunosuppressed (see below) should proceed to colposcopy even if HPV testing is negative. For people who are pregnant, colposcopy may be recommended, but can often be delayed until six weeks postpartum.

A colposcopy is an in-office procedure that allows a doctor to examine the cervix more in depth. When performing a colposcopy, your doctor will use a lighted microscope called a colposcope, which magnifies the cervix so it can be better visualized.

During the colposcopy, the doctor may also do a cervical biopsy to remove small pieces of cervical tissue. Mild cramping may occur during a cervical biopsy; however, it is relatively painless. The tissue samples are then sent to a lab for further examination.

Those With Elevated Risk of Cervical Cancer

Some people who have an increased risk of developing cervical cancer may need earlier or further follow-up. Conditions considered high-risk include:

  • People who are living with HIV, whether present from birth or contracted at any time
  • People who have received a solid organ or stem cell transplant
  • People who are immunosuppressed, such as those who are receiving immunosuppressive therapy for a rheumatoid disorder such as lupus or for inflammatory bowel syndrome
  • People who were exposed to diethylstilbestrol in utero (uncommon, and primarily older people)

This early testing and follow-up may include beginning annual Pap smears (for at least three years) one year after initiation of sexual intercourse and proceeding to colposcopy even with mild changes on a Pap smear. Guidelines are available that should be considered for anyone who meets these high-risk criteria.

Cervical Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

Treatment

A common way to treat LSIL is to take a "watch and wait" approach. In the past, doctors took a more active approach to low-grade lesions, but retrospective research has shown that the practice did nothing to reduce the risk of cancer. In fact, it was more likely to cause harm by exposing people to treatments they don't need.

Since low-grade dysplasia usually resolves on its own, medical treatment may not be needed. With that said, Pap smears and/or colposcopies may be performed at regular intervals to monitor the dysplasia and ensure it doesn't progress.

If the dysplasia progresses (as seen on colposcopy and biopsies), treatment may be needed to remove the lesion. This can usually be performed as an in-office procedure. Treatments include:

  • Loop electrosurgical excision procedure (LEEP) is a technique in which an electric current is sent through a wire loop to cauterize and remove abnormal cells.
  • Cryotherapy is a technique used to destroy abnormal tissue through freezing.
  • Cone biopsy, also known as conization, involves the removal of a larger, cone-shaped sample of abnormal tissue.
  • Laser therapy uses a tiny beam of amplified light to destroy abnormal cells.

Treatment during pregnancy is not recommended, even for HSIL (CIN2 or CIN3) due to the possibility of pregnancy-related complications, and referral to a gynecologic oncologist should be considered.

A Word From Verywell

The bottom line here is that the Pap smear result of LSIL is considered "abnormal" and requires further testing and possibly treatment. But the good news is that in most cases, it clears up on its own within two years.

Even so, regular check-ups with your doctor are critical to ensuring that any abnormal cells do not persist or progress. Remember, early detection is key to lowering your chances of developing cervical cancer.

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