CANCER OF THE CERVIX
The cervix is the part of the uterus connected to the upper vagina. It is the structure that dilates during childbirth to allow the baby to traverse the birth canal. There are two major types of cancer that develop from the cervix. Squamous cell cancers arise from the squamous epithelium that covers the visible part of the cervix. Adenocarcinomas arise from the glandular lining of the endocervical canal. About 85% of cervical cancers are squamous cell cancers and the remainder adenocarcinomas. Each of these major types has several subtypes that may require special treatment; otherwise they are all managed similarly. Squamous cell cancers are unique because there is a well established progression through premalignant changes before a cancer develops. These premalignant changes are easy to detect by a simple screening test called the Pap test.
The cause of cervical cancer is unknown. There is a strong association with certain subtypes of the Human Papilloma Virus (HPV) for the squamous cell cancers. HPV can be transmitted sexually, so there is an association with sexual activity. The strongest association, however, is that women who have been celibate all their lives almost never develop a squamous cell cancer of the cervix. They are at risk, however for an adenocarcinoma of the endocervix. Infection with HPV, which also causes genital warts, is common; cervical cancer is not. HPV changes are often noted on the Pap test report and should not cause alarm. If there are any premalignant changes diagnosed then they will be treated. Treatment of these premalignant changes is usually simple and almost 100% effective.
Sixty years ago cancer of the cervix was the leading cause of cancer deaths in women in this country, surpassing even those from breast cancer. The death rate began to fall in the 1940's and has continued to fall, in spite of the sexual revolution, third world immigration and the prevalence of HPV. The reason for this large decrease is unknown. It began before Pap test screening became prevalent. Cervical cancer is still the leading cause of cancer deaths in women in many third world countries. There are about 16,000 new cases diagnosed each year in the USA , with about 5,000 deaths. There are about 180,000 new cases of breast cancer each year and about 60,000 women die of lung cancer each year.
All sexually active women are at risk for the development of cervical cancer. The risk seems to be increased with smoking and promiscuity of the woman or her male partner. This is the standard text book explanation for an increased risk. But, in my experience, it is not a likely explanation for the patients that I have treated. It is not increased by the use of birth control pills, family history or the development of genital warts. Almost all cases occur in women who have not had regular screening with Pap tests. This is one cancer that can be prevented, in most cases, by screening for the premalignant changes.
Screening means to test for the presence of a cancer before there are any symptoms or findings on examination. If there are symptoms or abnormal findings on examination then a diagnostic test must be done; not a screening test. The major benefit of the Pap test is to detect changes on the cervix before they become cancerous. These premalignant changes are referred to as dysplasias or as intraepithelial neoplasias . They are easily and effectively treated.
When a Pap test is reported as abnormal a well established evaluation is begun. Only after this evaluation is completed can a diagnosis be made as to the true condition of the cervix. Only after the diagnosis is established can treatment be recommended. It is a major mistake to treat on the basis of an abnormal Pap test without a diagnosis. An abnormal Pap test is not a diagnosis. It is only an abnormal screening test that must be evaluated. This evaluation is described in ALL ABOUT PAP TESTS.
There may be no symptoms of a very early cervical cancer, but by the time it is large enough to detect visually it is usually symptomatic with abnormal bleeding. Often this abnormal bleeding occurs after sexual intercourse. Cancers must make new blood vessels as they grow. These new blood vessels are often abnormal and break easily which is why bleeding is a sign of cancer. The cancer also outgrows some of its blood supply, so portions of it are deficient in oxygen. This causes some of the cells to die and for the tissue to become infected. In the cervix this causes a watery or foul discharge that will be noticeable and resistant to most treatments for the usual vaginal infections.
As the cancer increases in size it usually grows laterally toward the pelvic wall. The tubes from the kidneys (ureters) that bring urine to the bladder pass through this area and they are easily obstructed. If that happens to both of the ureters, then this will result in renal failure, coma and death. If the cancer grows into the pelvic wall it will press on the nerves that go to the leg and cause unremitting leg pain. These are symptoms of an advanced cancer. Premalignant changes have no symptoms and are usually not noticeable on visual examination.
Cervical cancers usually do not spread early. They tend to be slow growing and cause most of their problems in the pelvis. Although distant metastases occur they are usually late events. Cervical cancers can spread by way of the lymphatic system . The lymphatic vessels drain from the cervix to clusters of lymph glands along the pelvic wall. The lymphatics follow the large blood vessels so the route of drainage is upward along the pelvic wall, then along the midline of the backbone and then to the chest. If the pelvic lymph nodes on one side of the pelvis become obstructed with cancer then that will cause swelling in the leg on that side. This is another sign of advanced cancer.
The diagnosis of cervical cancer is usually not difficult. It is usually big enough to be seen and can be biopsied. If it arises from up inside the cervical canal then it may not be visible. This will require that a portion of the cervix be removed for diagnosis. These large biopsies can be accomplished by either a LEEP or cone procedure. A major mistake is to rely on a Pap test to rule out a cancer in a woman who has symptoms or findings that could be due to a cancer. A normal Pap test never excludes a cancer. Cancer can only be excluded by the proper biopsies. It is known that about 10% of women with an obvious cancer of the cervix will have a Pap test that is essentially normal. This is because there is so much inflammation and dead cell debris that it masks the cancer cells. Very rarely, the cervix may be too small or inaccessible to biopsy properly. In these situations a simple hysterectomy may have to be done for diagnosis.
Whenever a cancer is diagnosed the next step is staging. This is a determination of the extent of the cancer. For cervical cancer this is determined by physical examination, chest x-ray, kidney x-rays and looking inside the bladder and rectum. CT scans and MRI scans can be done but they are not used to assign a stage. Likewise, surgical exploration is not used to assign a clinical stage.
| CLINICAL STAGES OF CANCER OF THE CERVIX
Stage I Cancer confined to the cervix
IA Invasive cancer detectable microscopically only
IA1 Invasion less than 3 mm and width less than 7 mm
IA2 Invasion more than 3 mm but less than 5 mm
IB All others, any visible cancer
IB1 Cervix less than 4 cm in diameter
IB2 Cervix greater than 4 cm
Stage II Spread to adjacent structures
IIA Spread onto the vagina
IIB Spread laterally toward the pelvic wall
Stage III More extensive but still within the pelvis
IIIA Extends to the lower vagina
IIIB Extends onto the pelvic wall, obstructed ureter
Stage IV Distant spread or involvement of a pelvic organ
IVA Involves the inside of the bladder or rectum
IVB Distant metastases, i.e. lung, liver or bone
|FIVE YEAR SURVIVAL RATES FOR CERVICAL CANCER
Stage I 80%
Stage II 65%
Stage III 30%
Stage IV 15%
These are somewhat misleading numbers. Certainly, almost all stage IA cancers will be cured. Stage IB cancers, if the nodes are negative and the surgical margins adequate will also almost all be cured.
If the cancer recurs then the outlook is generally poor. If initially operated then the recurrence can be treated with radiation. If initially irradiated then sometimes ultra-radical surgery can still be curative. If there is a recurrence in the cervix or vagina after the pelvis has been irradiated and there is no evidence of cancer anywhere else, then ultra-radical surgery can be done. This is called a total pelvic exenteration. The uterus, tubes, ovaries, bladder, colon and vagina are removed. Sometimes the vagina can be reconstructed and the colon reattached. A continent urinary reservoir can also be done.
Isolated recurrences elsewhere such as lung or liver can be removed surgically or irradiated if not removable. The treatment of isolated recurrences can be curative since cervical cancers do not usually spread widely throughout the body. Chemotherapy for recurrent cancer has not been very effective, but is often tried.
CERVICAL CANCER DURING PREGNANCY
When an abnormal Pap test is obtained on a woman who is pregnant the evaluation is modified. In general, the pregnancy has no effect on the cervical problem and the cervical problem has no effect on the pregnancy. However, the cervix is best not manipulated or biopsied during the first trimester because the risk a spontaneous miscarriage is about 20%. Should this happen, the biopsy will be blamed, although it will not have been the cause.
There is no urgency to diagnose a premalignant condition during pregnancy. All that is really necessary is to exclude or diagnose an invasive cancer. Often this can be accomplished by a colposcopic examination, without the need for any biopsy. The premalignant conditions can easily wait until 6 weeks after the baby is born to evaluate and treat. Sometimes however, biopsies and even cone biopsies must be done. The best time for these biopsies is the early second trimester because the risk for a spontaneous miscarriage has past and cervical manipulation during the third trimester risks premature labor.
If an invasive cancer is diagnosed during pregnancy, the treatment is the same as for those not pregnant. Except, treatment can be delayed until the baby is sufficiently mature to be delivered if the diagnosis is made after the 24th week of pregnancy. The baby will usually reach lung maturity sometime between the 32nd and 36th week.
The best plan is to stay up to date with Pap test screening and prevent the development of this cancer.