Cervical cancer is cancer of the cervix -- the opening of the uterus, extending into the upper end of the vagina. Some 12,000 American women will be diagnosed with cervical cancer this year. Thanks to effective screening, which can detect cervical precancers and cancers early, most of them can be cured.
With the advent of widespread screening by a vaginal smear test developed by George Papanicolaou in the 1950s (commonly known as the "Pap smear"), the number of deaths from cervical cancer has fallen dramatically -- from more than 35,000 per year to about 4,000 per year today.
Cervical cancer usually grows slowly over many years. Before true cancer cells develop, the tissues of the cervix undergo changes -- called dysplasia, or precancers -- that a pathologist can detect in a Pap smear. These changes range from mild dysplasia or cervical intraepithelial neoplasia (CIN1) to moderate (CIN2) to high-grade lesions (CIN3). They can also resemble cancer cells without invasion, also known as carcinoma in situ.
If left untreated, these precancers have the propensity to invade and become cancerous. Once they spread beyond the borders of the cervix, they can invade tissues more deeply, into either the vagina or the uterus, and ultimately metastasize to other parts of the body.
There are two main types of cervical cancer:
Cancers that have features of both cell types are known as mixed, or adenosquamous, carcinomas.
The most significant risk factor for cervical cancer is infection with the human papillomavirus (HPV), which can be transmitted during sex.
Papillomaviruses have been known to cause cervical dysplasia, or precancers, for more than two decades. More recently, DNA from these viruses has been found to exist in virtually all cervical squamous cell carcinomas (the most common type of cervical cancer).
By avoiding the following known risk factors for HPV infection, women can reduce their likelihood of developing cervical cancer:
Women without these risk factors rarely develop cervical cancer. Although all women can help protect themselves from disease by having their sexual partners use condoms, condoms do not provide complete protection from HPV infection because this virus (unlike HIV) can be spread by contact with any infected area of the body.
Cervical cancer, especially in its earliest stages, often causes no symptoms. That's why it's so important to see your doctor for regular screening with a Pap test.
When symptoms do occur, they may include the following:
These symptoms can be caused by cervical cancer or by a number of serious conditions, and should be evaluated promptly by a medical professional.
A Pap test is used to detect the possibility of a cervical cancer or dysplasia (precancer).
If a Pap test shows an abnormality, your doctor will perform a biopsy (by removing a sample of cervical tissue for microscopic examination). A gynecologist will often use a colposcope (a viewing tube attached to magnifying binoculars) to find the abnormal area and remove a tiny section of the surface of the cervix, which a pathologist will examine to see if it contains precancer or cancer cells. He or she may also perform a Schiller test, in which the cervix is coated with an iodine solution. Iodine causes the healthy cells to turn brown, while abnormal cells appear white or yellow.
If the diagnosis isn't clear, a surgeon may remove a slightly larger, cone-shaped piece of tissue (called a cone biopsy). At Tata Memorial Centre, cone biopsies are often performed by loop excision, in which an electrical current is passed through a thin wire loop to remove the sample tissue. Loop excision takes only about 10 minutes under local anesthetic. The cone biopsy is also a treatment, and can completely remove many precancers and early cancers. More than 90 percent of cervical cancers can be halted with this technique without further treatment.
Cytoscopy & Other Imaging Tests
If your doctor suspects that the cancer may have spread beyond the cervix, you may have cytoscopy (examination of the bladder using a lighted tube), proctoscopy (examination of the rectum), a chest x-ray, or other imaging tests -- such as a computerized tomography scan (CT scan) of the abdomen and pelvis to check for metastatic disease, or magnetic resonance imaging scan (MRI scan) of the pelvis to check the extent of local disease.
Options for treating cervical cancer depend chiefly on the stage of disease -- the size of the cancer, the depth of invasion, and whether the cancer has spread to other parts of the body. The primary forms of treatment are surgery and combined radiation therapy and chemotherapy.
Carcinoma In Situ
These cancers are preinvasive and can be treated conservatively, sparing the uterus. Options for treatment include
These treatments are almost always effective in removing precancers and stopping them from developing into true cancers.
Early Cervical Cancer (Stages I-IIA)
For early cervical cancers that are confined to the cervix, surgical options may include hysterectomy (removal of the uterus), sometimes along with the tissue next to the uterus. Lymph nodes from the pelvis are also removed and examined for cancer cells. If the cancer is associated with "high-risk" features -- such as involvement of the pelvic lymph nodes, invasion of the lymph channels or blood vessels of the cervix, or involvement of the tissue along the uterus -- doctors recommend chemotherapy combined with radiation therapy.
Advanced Cervical Cancer (Stages IIB-IVA)
If cervical cancer has spread beyond the cervix and into the surrounding pelvic tissues, surgery alone is usually not an effective cure. Patients with this degree of invasive cancer have traditionally also been treated with radiation therapy (the use of x-rays or other high-energy waves to kill cancer cells and shrink tumors), either alone or in addition to surgery.
In recent years, however, there has been a major shift in the treatment of advanced cervical cancer. Based on the results of large clinical trials, the standard of care for regionally advanced cervical cancer is now chemotherapy combined with radiation therapy. The radiation therapy may be delivered externally and/or internally (by placing an implant to deliver radioactive material immediately around the cervix).
Stage IVB & Recurrent Cervical Cancer
For women whose cancer spreads beyond the pelvis (into the lungs or liver, for example) or who have recurrent disease, treatment is aimed at reducing cancer-related symptoms in order to improve a patient's quality of life, and hopefully to prolong her survival. Chemotherapy is the primary modality of treatment for these patients, and several drugs are available for treating these women.
For women whose disease recurs in the pelvis, extensive surgery may be the only curative option and requires a highly experienced multidisciplinary team.