A cone biopsy, also known as conization, is a surgical procedure that involves removing a cone-shaped piece of tissue from the cervix. The name comes directly from the shape of the excised tissue, which includes the transformation zone where most cervical cell changes originate. The procedure serves two purposes: it provides a large, deep tissue sample for a definitive diagnosis and often removes all the abnormal tissue, serving as a primary treatment.
Indications for the Procedure
A cone biopsy is recommended when initial screening suggests the presence of high-grade abnormal cells that could become cancerous. This usually follows an abnormal Pap test and colposcopy with directed biopsies that leave questions about the extent or nature of the cellular changes. The procedure is necessary to confirm the diagnosis of high-grade Cervical Intraepithelial Neoplasia (CIN), specifically CIN 2 or CIN 3, or to rule out microinvasive cancer.
A cone biopsy is also required if a colposcopy is deemed “unsatisfactory,” meaning the transformation zone where abnormal cells form could not be fully visualized. When smaller initial biopsies are inconclusive or suggest a lesion extending into the endocervical canal, the cone biopsy provides a deeper, more comprehensive tissue sample.
Details of the Surgical Process
A cone biopsy is performed in an outpatient surgical center or hospital setting and usually takes 15 to 30 minutes. The patient is placed in a position similar to a pelvic exam, and the procedure requires anesthesia, which may be local, regional, or general. The surgeon inserts a speculum to access the cervix and may use a magnifying instrument, called a colposcope, to guide the tissue removal.
There are two primary methods for excision: Cold Knife Conization (CKC) and the Loop Electrosurgical Excision Procedure (LEEP). CKC uses a surgical scalpel to remove the tissue and is typically performed under regional or general anesthesia. CKC yields a larger specimen with less thermal damage to the margins, which is advantageous when suspicion for invasive disease is high and precise margin assessment is needed.
The LEEP technique uses a thin wire loop heated by an electrical current to cut away the abnormal tissue. LEEP is often preferred because it is faster, can frequently be performed in an office setting with local anesthesia, and results in less blood loss. The electrical current can cause thermal artifact at the edges, making margin assessment slightly more difficult for the pathologist compared to a CKC specimen. After the tissue is removed, the surgeon controls any bleeding using sutures, cauterization, or a surgical paste.
Recovery and Post-Procedure Care
Patients commonly experience mild to moderate cramping following a cone biopsy, similar to menstrual discomfort, which can be managed with over-the-counter pain medication. Vaginal discharge is expected and may initially appear as light bleeding or spotting. This bloody or brown discharge will transition to a clear and watery consistency over the next two to three weeks before resolving.
To prevent infection and allow the cervix to heal fully, patients must avoid placing anything into the vagina for four to six weeks, or until a doctor confirms healing. This includes abstaining from sexual intercourse, douching, and the use of tampons. Strenuous activity, heavy lifting exceeding ten pounds, and soaking in baths, hot tubs, or pools should also be avoided during recovery.
Immediate medical attention is necessary if serious complications arise. Warning signs include heavy vaginal bleeding (soaking more than one sanitary pad per hour for two consecutive hours) or the passage of large blood clots. Other signs are a fever of 101°F (38.3°C) or higher, chills, or foul-smelling vaginal discharge indicating infection. The next menstrual period may arrive late or be heavier than usual, which is a temporary effect.
Interpreting Pathology Results and Follow-Up
The removed tissue is sent to a laboratory where a pathologist examines it under a microscope to determine the precise diagnosis and the status of the margins. The most significant finding is the status of the surgical margins, referring to the edges of the removed tissue. A “negative” or “clear” margin means no abnormal cells were found at the edges, suggesting all affected tissue was successfully removed.
If margins are reported as “positive” or “involved,” abnormal cells were found at the edge of the specimen, indicating some abnormal tissue may remain on the cervix. A positive margin does not automatically require another procedure, as remaining abnormal cells often resolve on their own if the diagnosis was not invasive cancer. However, a positive margin may prompt a discussion about a repeat excision or more frequent follow-up.
Regardless of the margin status, a comprehensive follow-up plan monitors the cervix for any recurrence of abnormal cells. This typically involves repeat Pap tests and Human Papillomavirus (HPV) testing, often beginning six months after the cone biopsy. If surveillance tests consistently return normal results, the patient can return to a standard screening schedule.