Technology & Science

Cervical cancer

Nearly 1,400 Canadian women will be diagnosed with cervical cancer in 2006 and approximately 390 will die from the disease, health officials predict.

Cervical cancer incidence and death rates have dropped steadily over the past few decades, in large part owing to regular Pap test screening. According to the Canadian Cancer Society, incidence rates have declined two per cent per year from 1995 to 2004.

Still, nearly 1,400 Canadian women were diagnosed with cervical cancer in 2006, according to health officials. They say this cancer can be prevented and, in most cases, can be cured if treated early.

What is cervical cancer?

This type of cancer begins in the cervix, the lower part of the uterus or womb, which opens into the vagina. 

Cervical cancer quick facts:

  • The human papilloma virus (HPV) causes the majority of cervical cancers.
  • There are over 100 types of HPV and only a few are high-risk types. Only a fraction of women infected with high-risk types will develop cervical cancer.
  • Cervical cancer is called the 'silent infection.' Women don't necessarily feel it because it causes effects at the cellular level of the cervix.
  • The only way to detect cervical cancer is with a Pap smear. Cells are taken off the cervix and sent to a lab for testing.

Health Canada guidelines:

  • Get a Pap test at age 18 as part of your routine health examination, or as soon as you become sexually active.
  • A second test should be taken after one year, especially if you begin screening after age 20.
  • If your first two tests show no abnormality, you should be re-screened every three years to age 69. However, you do not need to be re-screened if you have never had sexual intercourse or if you have had a hysterectomy and your previous tests were normal.

Sources: Health Canada, Canadian Cancer Society, U.S. Centers for Disease Control and Prevention

Early changes in the cells of the cervix can happen without pain or other symptoms. If not found and treated, cell changes in the cervix can grow into cancer, which can spread to other parts of the body.

There are two main types of cervical cancer. The most common type, squamous cell cancer, starts in the cells that line the surface of the cervix. Adenocarcinoma, which is less common, starts in the mucous-secreting glandular tissue of the cervix. The cervix has these gland cells along the inside of the passageway that runs from the cervix to the womb.

What causes cervical cancer?

A virus called human papilloma virus (HPV) is responsible for most cases of cervical cancer. HPV is spread through sexual contact. The virus is said to infect half of all sexually active women between ages 18 and 22 in North America. In most women, the virus clears up on its own, but if the infection persists, it can lead to cervical cancer.

On July 2006, Health Canada approved a vaccine that protects against the human papilloma virus. Gardasil has been approved for females between nine and 26 years of age.

"Until now, we have only been able to react to the effects of HPV in women," said Dr. Guylaine Lefebvre, the president-elect of the Society of Obstetricians and Gynecologists of Canada.

"Now we are talking about preventing most of the serious diseases caused by HPV." Since the vaccine doesn't prevent infection from all strains of HPV, women would still need to get a Pap test to screen for the virus.

Other factors that appear to increase the risk of cervical cancer include: 

  • Multiple sex partners or a partner who has had a number of sexual partners.
  • Sexual activity at a young age.
  • Smoking.
  • Suppression of the immune system by drugs after an organ transplant or condition such as AIDS.

What are the symptoms?

In general, early cervical cancer produces no signs or symptoms. As the cancer advances, the following symptoms may appear: 

  • Abnormal bleeding after intercourse, between periods or after menopause.
  • Increased vaginal discharge.
  • Health officials say these symptoms may be caused by cancer or by other health problems. Contact your doctor if you have any of these symptoms.

How is cervical cancer detected?

The Pap test is used to detect cervical cancer before it has fully developed and when treatment can be effective.

During the test, the doctor brushes cells from the cervix, smears them onto a glass slide, and then sends the sample to a lab.

According to Health Canada, the death rate from cervical cancer has dropped almost 50 per cent since the introduction of the Pap test.

What treatments are available?

Treatment depends on the stage of the cancer. It may include the following:

  • Surgery, which involves removing cancerous cells.
  • Radiation therapy, which uses high-energy x-rays or other types of radiation to kill or shrink the cancer cells.
  • Chemotherapy, which utilizes drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing.