High-grade squamous intraepithelial lesion (HSIL) is a finding from a Pap test or biopsy indicating the presence of significantly abnormal cells on the surface of the cervix. This condition is not cancer, but it is considered a direct precursor to cervical cancer and requires intervention to prevent progression. Treatment is highly effective, and the goal is to remove all affected tissue while preserving the function of the cervix.
Understanding High-Grade Squamous Intraepithelial Lesion
HSIL represents a severe degree of abnormal cell growth on the cervix, typically identified during routine screening. Pathologists often correlate this diagnosis with cervical intraepithelial neoplasia grade 2 (CIN 2) or grade 3 (CIN 3), which indicates that the abnormal cells have penetrated at least two-thirds of the epithelial layer. The presence of HSIL confirms a persistent infection with a high-risk type of the Human Papillomavirus (HPV).
Treatment is necessary because, unlike low-grade lesions that often resolve on their own, HSIL rarely regresses. The risk of an untreated HSIL lesion progressing to invasive cervical cancer is substantial, with estimates ranging from 5% to over 20% if left untreated for several years.
The intervention aims to remove the “transformation zone,” which is the area on the cervix where the abnormal cells originate and where the risk of malignancy is highest. By excising this tissue, the treatment simultaneously serves a diagnostic purpose, ensuring that no undetected invasive cancer is present beneath the surface of the lesion. This dual function of treatment and diagnosis makes an excisional approach the standard of care for most patients.
Primary Excisional Treatments
The definitive treatment for HSIL involves excising the affected tissue rather than simply destroying it. The two primary excisional methods are the Loop Electrosurgical Excision Procedure (LEEP) and Cold Knife Conization (CKC). Both procedures aim to remove a cone-shaped piece of the cervix that includes the transformation zone.
The LEEP, also known as Large Loop Excision of the Transformation Zone (LLETZ), is the most common technique, often performed in an outpatient setting under local anesthesia. It uses a thin wire loop heated by an electrical current to quickly and precisely cut away the abnormal tissue. This procedure is minimally invasive and typically results in a shorter recovery time for the patient.
Cold Knife Conization (CKC) is a traditional surgical method that uses a scalpel to remove the cone-shaped specimen. CKC is usually reserved for cases where the lesion extends higher into the cervical canal, if the margins of a previous LEEP were unclear, or if a glandular abnormality is suspected. Because it is performed with a scalpel, CKC typically requires general or regional anesthesia and offers the advantage of producing a tissue sample with minimal thermal damage to the edges.
The most important factor determining the success of either excisional procedure is achieving “clear margins.” This means that the pathologist examining the excised tissue confirms that the abnormal cells were completely surrounded by healthy, unaffected tissue. If the margins are found to be positive, the risk of residual or recurrent disease is significantly increased, often prompting a discussion of a second procedure or intensified surveillance.
Although ablative treatments like cryotherapy or laser ablation are generally not preferred for HSIL. Excision is favored because it provides a complete tissue sample for pathological analysis, ensuring that the diagnosis is not underestimated and ruling out the presence of occult invasive cancer.
The Patient Experience: Procedure and Recovery
The patient experience differs slightly between the two primary excisional procedures, mainly due to the type of anesthesia used. LEEP is an office-based procedure, where the patient receives local anesthesia injected directly into the cervix, minimizing discomfort during the short procedure. CKC is typically performed in an operating room under general or regional anesthesia, ensuring the patient is asleep or completely numb.
Immediately following the procedure, patients should expect some side effects as the cervix begins to heal. Mild, menstrual-like cramping is common for the first few days and can usually be managed effectively with over-the-counter pain relievers. Vaginal discharge is also expected and may initially be dark brown or black, which is often due to a paste applied to the cervix to stop bleeding, or it may be a watery, yellowish discharge for up to three weeks.
Specific activity restrictions are necessary to prevent infection and excessive bleeding during the four to six weeks it takes for the cervix to fully heal. Patients are advised to practice pelvic rest, which involves abstaining from sexual intercourse and avoiding the use of tampons, douches, or swimming. Strenuous physical activity, including heavy lifting exceeding five kilograms, should also be avoided for at least one to two weeks.
Patients are given clear instructions on signs that warrant urgent medical attention, such as soaking more than one sanitary pad per hour with bright red blood or developing a fever and foul-smelling vaginal discharge. For those who wish to become pregnant in the future, it is important to note that extensive removal of cervical tissue can slightly increase the risk of preterm birth. However, for the majority of women, this risk remains low and is a necessary trade-off for the prevention of cervical cancer.
Long-Term Follow-Up and Monitoring
Treatment for HSIL is highly successful, but it marks the beginning of a crucial period of long-term surveillance. The risk of the lesion recurring or a new lesion developing remains higher than in the general population. The primary goal of monitoring is to detect any residual or recurrent disease early.
The standard follow-up protocol involves co-testing, which combines a Pap test (cytology) with a high-risk HPV test. This combined testing method is highly sensitive for detecting any persistent or new abnormalities. The first round of co-testing is typically scheduled six months after the excisional procedure to ensure that the initial treatment was curative.
If the initial follow-up test is negative, co-testing is generally repeated annually for several years. Current guidelines recommend that surveillance continue for at least 20 to 25 years after the initial treatment, even if multiple consecutive tests are negative. This extended monitoring period is necessary because the underlying HPV infection can persist and lead to new lesions years later. Adherence to this surveillance schedule is paramount because it provides the best opportunity for early intervention should any new abnormalities arise.