Cervical Cancer

The cervix (or neck of the uterus) is the lower portion of the uterus that opens into the vagina. The cervix has a special surface that does not exist elsewhere in the uterus. When cervical cancer develops, it starts here in what is known as the “transformation zone”. Cervical cancer is completely different from other cancers that can be found elsewhere in the uterus.

Cervical cancer is the second most frequent female cancer worldwide. It is usually diagnosed in women in their 40’s or 50’s. Fortunately, thanks to screening and treatment methods, the number of deaths associated with this type of cancer have dropped in Quebec (and industrialized countries) over the past few decades.

There are two types of cancer precursor: mild precancer and severe precancer. Most cases of mild precancer (more than 80%) disappear by themselves. On the other hand, because some of them progress to severe precancer, they must be closely monitored. Nearly 30% of severe precancer cases develop into cancer over a period of 30 years. They must therefore be treated. Precancerous lesions do not cause any symptoms. The only way to detect them is to consult a doctor so that he/she can perform a screening test. Various treatments exist for precancerous lesions. The women treated can still become pregnant.

WHAT METHODS ARE USED TO SCREEN FOR CERVICAL CANCER?

A screening test can detect a disease before it produces any symptoms. There are various ways to detect precancers and cervical cancer.

CYTOLOGY

Today, a Pap smear is the recommended test to determine the presence of precancers or cervical cancer early on. It was developed in the 1940’s by Dr. George Papanicolaou, hence the name PAP.

Your doctor will carry out a Pap test during a gynecological or pelvic examination. When he/she inserts the speculum, the outside surface of the cervix becomes visible. The surface of the cervix differs from the rest of the uterus and this makes it vulnerable to the action of certain human papilloma viruses (HPV). Your doctor knows the cervical zone at risk and will take a sample from that area. For a quality specimen, it is preferable that you are not menstruating.

A wooden or plastic spatula, or perhaps a tiny brush, is used for the test which is quick and painless. Cells are taken and immediately spread on a microscope slide and treated with a fixative. In the laboratory, the slide is stained and the cells examined under a microscope to detect whether there are any signs of precancer or cancer.

There is a new technique, “Liquid-Based Cytology”, but it is rarely available in the public system. The most recent and most comprehensive studies have been unable to establish its superiority over so-called conventional cytology in terms of detecting severe precancer or cancer itself.

The result sent to your doctor will fall into one of the following categories: normal, atypical (ASC-US), mild precancer (LSIL), severe precancer (HSIL), or cancer. If your results are abnormal, your doctor will tell you whether it is preferable to repeat the test, have a different test or have a diagnostic examination.

The first PAP test should be done at age 21. If everything is normal, it can then be done every 2 years or as your doctor advises.

A new form of cytology has been available for some years (liquid-based cytology). If your doctor selects this method, he/she will take a sample in the same way but will place it in a tube containing a special liquid instead of spreading it on a microscope slide. The advantage of this form of cytology is that it gives clearer slides that cytology technicians can read more easily (they can also read more of them in a day). In addition, if atypical cells are found, an HPV test (see next section) can be done on the remaining liquid without you having to return to your doctor’s office to provide a second sample. However, there is no evidence that this type of cytology is “better” than conventional cytology in identifying severe precancer and cancer itself.

COLPOSCOPY

The diagnostic examination is called a “colposcopy”. It gives a magnified view of the cervix. A little vinegar (5% acetic acid) is applied so that secretions can be cleaned away and any abnormal zones seen. A weak iodine solution is sometimes used at the end to outline suspicious areas.

The doctor can also perform a biopsy (3-5 mm), and take a small scraping from inside the cervix. If these specimens show severe precancer is present, your doctor will suggest treatment to remove this infected tissue. It is estimated that around 30% of severe precancers will develop into cancer over a period of 30 years. The treatment will prevent this progression. It may involve freezing the cervix (cryosurgery), laser vaporization, removal using an electrosurgical loop or, alternatively, a scalpel. The treatment is effective in 85-90% of cases, and complications are rare (less than 10%). These treatment methods do not affect your ability to become pregnant. Some follow-up visits are suggested afterwards to ensure the treatment has been successful.

HPV TEST

An HPV test is a simple, safe way to determine whether you have an HPV infection of your cervix. It is very similar to a PAP test: a cervical sample is taken and sent to the laboratory to check whether cancer-causing HPVs are present. The test is read by an automated machine. The result is shown as the presence or absence of cancer-causing HPVs. It should be noted that there is no clinical test to detect low-risk HPVs.

For the time being, the HPV test is mainly recommended for the “triage” or sorting of atypical cytology results. If your cytology gives this type of result (atypical or ASC-US), there are three ways to follow-up:

• Repeat the PAP test after six months, and have a colposcopy if the result is still atypical or abnormal.
• Have a colposcopy immediately.
• Have an HPV test, and then a colposcopy only if the HPV test is positive.

A number of studies have shown that the HPV test following atypical cytology results allows more precancers to be detected, while minimizing colposcopies in women with no cervical abnormality.

Some researchers and physicians believe that the HPV test could be used for screening purposes, replacing the PAP test or with the PAP test. We do not have sufficient evidence at this point to suggest that the HPV test should replace cytology; however, adding the HPV test to cytology may be considered in certain circumstances.

When the HPV test is used for detection, it should only be in women over thirty (30) years of age. Most HPV infections in women under 30 are temporary and there are no consequences. If the PAP and HPV test results are negative, you can be reassured that you have no precancer and the test need only be repeated in 3-5 years, which some women may see as an advantage.

If the PAP test and HPV test results are abnormal, your doctor will advise you to have a colposcopy. If the PAP test is atypical and the HPV test abnormal, your doctor will also advise a colposcopy. If the PAP test is clearly abnormal, your doctor will advise a colposcopy even if the HPV is negative.

Finally, if your PAP test is normal and only the HPV is positive, your doctor will advise to you to repeat both tests in 12 months’ time. If one of the results is again abnormal, he/she will refer you for a colposcopy.