A cone biopsy is a surgical procedure in which a cone-shaped tissue sample from the cervix is removed for examination. Also called cervical conization, a cone biopsy is done to diagnose cervical cancer or to remove cancerous or precancerous tissue.
The cervix is the neck-shaped opening at the lower part of the uterus. The American Cancer Society estimated that in 2003, approximately 12,200 women would be diagnosed with cancer of the cervix and 4,100 women
A cone biopsy is performed to diagnose cancer of the cervix or to detect precancerous changes. The procedure is often recommended if a Pap test indicates the presence of abnormal cells. In some cases, a cone biopsy may be used as a conservative treatment for cervical cancer for women who wish to avoid a hysterectomy (surgical removal of the uterus).
The risk of developing cervical cancer increases with age through a woman's 20s and 30s; the risk remains about the same for women over the age of 40. Minority women and women of low socioeconomic status have higher rates of cervical cancer and an increased mortality rate. According to the Centers for Disease Control and Prevention (CDC), African-American, Asian-American, and Hispanic women have a higher-than-average incidence of the disease, while African-American and Hispanic women have a higher rate of cervical cancer-related death.
The procedure is performed with the patient lying on her back with her legs in stirrups. General anesthesia is commonly used, although regional (spinal or epidural) or local anesthesia may also be used. A speculum is inserted into the vagina to hold it open during surgery.
There are several different methods that may be used to perform a cone biopsy. Cold-knife conization is the removal of a cone-shaped wedge of tissue with a scalpel (surgical knife). The tissue may also be removed using a carbon dioxide laser (called laser conization). A loop electrosurgical excision procedure (LEEP) uses low-voltage, high-frequency radio waves to excise the tissue. Some surgeons choose to cover the open cervical tissue with flaps of tissue stitched into place.
The tissue sample will then be examined under a microscope for the presence of cancerous cells. If abnormal cells are found around the edge of the biopsy, then further surgery will be required to excise any remaining cancer. If there is evidence of invasive cancer (i.e., the cancer has spread to surrounding tissues), then other treatments (more extensive surgery, chemotherapy, and/or radiation) may be recommended.
A number of tests may be performed prior to cone biopsy to determine if precancerous or cancerous cells exist. A Pap test involves scraping the cervix for a sample of cells and then staining and examining the cells for any abnormalities. Colposcopy is a procedure that allows a physician to examine a woman's cervix and vagina using a special microscope called a colposcope. A cervical biopsy involves the extraction of a smaller tissue sample and is less invasive than a cone biopsy. Based on the results of these tests, a cone biopsy may be indicated if moderate to severe cell abnormalities are found.
As cone biopsy is commonly performed under general anesthesia, the patient is usually instructed to refrain from eating and drinking after midnight on the day of surgery.
After the procedure, the patient may experience some cramping, discomfort, or mild to moderate bleeding. The biopsy site may take up to six weeks to completely heal. The patient will be instructed to avoid intercourse, tampons, and douches for at least three weeks following the procedure.
Bleeding during and after cone biopsy is the most common complication. Rarely, uncontrolled bleeding during the procedure may result in an emergency hysterectomy. Other potential complications include reaction to the anesthesia, infection of the biopsy site, injury to the uterus or other tissues, cervical stenosis (when the cervical canal narrows or becomes closed), and failure to remove all cancerous tissue. If too much tissue is removed during a cone biopsy so that the internal opening of the cervix to the uterus (called the internal os) is affected, a woman may have difficulty carrying a pregnancy to term, increasing her risk of miscarriage or premature birth.
Numerous studies have indicated that cone biopsy is successful in excising all cancerous tissue in 90% of patients with cervical cancer.
Two to 8% of women who undergo a cone biopsy will experience bleeding for up to two weeks. One study found that cervical stenosis occurs at a rate of 3–8%, depending on the method of conization.
Cryotherapy (freezing and destroying of abnormal cells) or laser vaporization (using a laser to destroy abnormal cells) may be used to treat early-stage cancer. A hysterectomy may be necessary to remove more invasive cancer. In a subtotal hysterectomy, only the uterus is removed. In a radical hysterectomy, the uterus, cervix, ovaries, fallopian tubes, lymph nodes, and lymph channels are removed. The type of hysterectomy performed depends on how far the cancer has spread. In all cases, menstruation stops and a woman loses the ability to bear children.
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American Cancer Society. 1599 Clifton Road NE, Atlanta, GA 30329. (800) ACS-2345. http://www.cancer.org .
American College of Obstetricians and Gynecologists. 409 12th St., S.W., PO Box 96920, Washington, D.C. 20090-6920. http://www.acog.org .
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Stephanie Dionne Sherk
A cone biopsy is usually performed by a gynecologist who specializes in the areas of women's general and reproductive health, pregnancy, labor and delivery, and prenatal testing. Tissue samples are analyzed by a pathologist who specializes in the diagnosis of diseases from microscopic analysis of cells and tissues. The procedure is generally done on an outpatient basis in a hospital or doctor's office.