Wednesday, June 11, 2008

Cancer of the Cervix

Many would recall that the late Hong Kong celebrity Anita Mui lost her life to cancer of the cervix in 2003. And many wondered: Isn’t cancer of the cervix supposed to be a largely preventable disease? What have we understood about the disease?

Cancer, in general, is number one killer in Singapore. One in every three Singaporeans will develop cancer at some point in their lives. One in four Singaporeans is destined to loose his or her life to the disease.

Against such alarming statistics, cancer of the cervix represents one of the success stories in our continuous struggle against cancer. In countries with a good health-care system in place, the consistent application of the three-pronged strategy of prevention, early detection and improved treatment has, to a significant extend, tamed the beast that is cervical cancer. While cancer of the cervix is the second commonest cancer affecting women all over the world, it has been relegated to the sixth position in Singapore. Cervical cancer, however, has not become a disease just of the developing world. It remains a significant scourge in developed societies.

What is cervical cancer? What causes it? Who are at risk? How can women be protected against it?

The cervix is located at the lower end of the womb; it is the entrance of the womb, so to speak. The growth of cancer in this region is closely related to infection of the area by a family of viruses known as the human papilloma virus (HPV). This virus can be transmitted by sexual contact. Hence, women who are sexually active, particularly women with multiple sexual partners, are more at risk. The other significant risk factor for cervical cancer is smoking. There is controversy surrounding the use of oral contraceptive and multiple childbirths leading to increased risk.

The Pap (Papanicolaou) smear is the main test, since its introduction in the 40’s, for detection of pre-cancerous changes in the cervix so that therapy can be instituted before a full-blown cancer develops. This simple test has reduced the incidence of cervical cancer by 70%. A Pap test can be done in a doctor’s office or a hospital. While a woman lies on an examination table, the clinician inserts a speculum into her vagina to widen it. A sample of cells is taken from the cervix with a wooden scraper and/or a small cervical brush. The specimen (or smear) is placed on a glass slide and preserved with a fixative, or is rinsed in a vial of fixative, and is sent to a laboratory for examination. Current general guidelines recommend that women have a Pap test at least once every 3 years, beginning about 3 years after they begin to have sexual intercourse, but no later than age 21. It is safe to wait 3 years, because cervical cancer usually develops slowly. Testing for the presence of the causative human papilloma virus is also increasingly used.

The latest breakthrough in the fight against cervical cancer is the availability of vaccines against human papilloma viruses. The currently available vaccine GardasilĂ” confer immunity to the common strains of human papilloma viruses that causes approximately 70% of all cervical cancer cases. Vaccination is estimated to be able to eventually prevent half of all aggressive pre-cancerous changes and two third of all cervical cancers. The vaccine is generally safe and well tolerated. The current recommendation is that the vaccine should be administered to all girls and women between the ages of 9 and 26.

While the human papilloma virus vaccine is a major advance in the prevention of cervical cancer, but it will not replace the need for other preventive strategies, such as the Pap smear. Pap smear screening is of paramount importance since HPV immunization is not effective in clearing infections or pre-cancerous changes that are already present.

The strategy for prevention of cervical cancer in future is likely to combine vaccination with screening by regular Pap smear. Not forgetting, the best that medical technology offers, will have little impact on the disease if the strategies do not gain widespread implementation and acceptance by women at risk. Medical advance has delivered the solution. It is up to us now, let’s get the word out and relegate cancer of the cervix to the pages of history.

Dr Wong Seng Weng
MBBS (Singapore), MRCP (UK), FAMS (Medical Oncology)
Consultant Medical Oncologist & Physician
The Cancer Centre, Paragon Medical