cervical cancer screening and prevention

1. What is Cervical Cancer?
Cervical cancer is a malignant cancer of the cervix. The cervix (or neck of the uterus) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. Cervical cancer is the 6th most common cancer affecting women in Singapore. It is however the second most common cancer affecting women worldwide with 500,000 women diagnosed per year. This means a woman dies of cervical cancer every 2 minutes worldwide.


2. How is Human Papillomavirus (HPV) linked to Cervical Cancer?
Contrary to what many people think, cervical cancer is not a hereditary condition. In fact, the majority of cases are caused by a virus called Human Papillomavirus or HPV. HPV is a very common virus and it was found that in USA, up to 50% of couples who have ever been sexually active are likely to be infected with an HPV virus at some time in their lives. The risk is increased with earlier age of intercourse and increase number of sexual partners. There are over 100 types of HPV but only 15 of them are high risk types associated with cervical cancer and these are the ones of concern. 90% of women are able to clear the HPV infection. In 10% of women with persistent or recurrent HPV infections however will progress to pre-cancer and finally cervical cancer if nothing is done to detect this change and to treat it. The virus cancer link works by triggering alterations in the cells of the cervix once infected leading to pre-cancer changes called CIN I, II, III (occurs mainly in the 20s to 40s). If this is not detected or treated, it will progress to cervical cancer (occurs mainly in the 30s to 50s). It takes months from the time of infection to develop CIN but about 10 years to progress to cancer. HPV infection does not lead to long term natural immunity so every woman is at risk. Women who have problems with their immune system are at increased risk of cervical cancer, especially if they have been exposed to HPV. Factors that affect your immune system and can increase your risk of cancer of the cervix are:
• Smoking
• Human immunodeficiency virus (HIV) infection


3. Prevention of Cervical Cancer
Primary prevention
Getting vaccinated with Gardasil or Cervarix vaccines can prevent the initial HPV infection at the point of exposure. Being immune to HPV infections would reduce the risk of cervical precancer and cancer. To be most effective, the HPV vaccines should be given before a person starts having sexual intercourse and is licensed for as young as 9 years old. In the United States, UK, Western Europe, Australia, New Zealand and South Korea for example, these vaccines are routinely given to 12 year old girls while they are still in school. We do not have this type of vaccination policy in Singapore yet. Women who are already sexually active will also benefit from HPV vaccination especially if they have not been infected with HPV infection yet.  Women who previously have had abnormal cervical cytology, genital warts, or precancerous lesions can also be vaccinated, although the protection may be less effective but the vaccines would still offer them protection from the other common strains in which they have not been infected with yet.
Since the initial approval for the use of HPV vaccination were for women up to 25-26 years old, new evidence suggests that the HPV vaccines are effective in preventing cervical cancer for women up to 45 years of age so much so that in countries like Australia, New Zealand, Japan, Israel, most of South East Asia, Africa, Central and South America for example, these vaccines are now licensed for use in females up to 45 years of age for the prevention of cervical cancer. It will probably be a matter of time before the majority of countries follow suit. Women who are currently pregnant and those who already have cervical cancer should not be vaccinated.
Although there are 15 types of HPV that are associated with cervical cancer, the 2 commonest are HPV type 16 and 18 which are associated with 70% of cervical cancer.  There are 2 vaccines that can protect women from these HPV infections. Gardasil® protects against HPV types 16, 18, 6 and 11 (type 6 and 11 cause 90% of genital warts) and Cervarix® protects against types 16 and 18. It is important to realize that these vaccines do not protect against all cancer-causing types of HPV (you may be still at risk of getting the remaining 30%), so routine pap smear tests are still necessary.

Secondary prevention
Routine regular pap smears remain the gold standard for the early detection, diagnosis and treatment of HPV-associated pre-cancerous lesions and this is universally accepted all round the world. Pap smears and HPV vaccination can be the greatest defenses for cervical cancer. The purpose of a pap smear is to collect cells from your cervix, which is the lower end of your uterus. The pap smear can detect pre-cancerous changes early which can be removed before they turn cancerous. In Singapore the risk of a woman getting cervical cancer is 1:180 if she goes for regular pap smears, this risk decreases to 1:200 if she has completed her HPV vaccination but the best would be if she has her regular pap smears and completes her HPV vaccination as her risk decreases to 1:500. Only sexually active women need a pap smear test and they should start from the age of 25 onwards in Singapore (it is 21 years old in western countries). If a woman is sexually active for 3 years even if she is under 21 years of age, a pap smear is also recommended. The minimal standard is for pap smears to be repeated at least every 3 years until 65 provided there are no abnormalities.

Other methods of prevention
Limit the amount of sexual partners you have. Studies have shown women who have many sexual partners increase their risk for cervical cancer as they also are increasing their risk of developing HPV infections which are the main cause for cervical cancer.
Quit smoking or avoid secondhand smoke. Smoking cigarettes increases your risk of developing many cancers, including cervical cancer. Smoking combined with an HPV infection can actually accelerate cervical dysplasia. Your best bet is to kick the habit.
If you are sexually active, use a condom. Having unprotected sex puts you at risk for HIV and other STD's which can increase your risk factor for developing cervical cancer.


4. Are there any symptoms?
The early stages of cervical cancer often cause no symptoms. This is why it is so important to have regular cervical pap smear tests - they are currently the recommended way of screening and detecting abnormal cervical cell changes and the early signs of cervical cancer.
If cervical cancer does cause any symptoms, the most common one is abnormal bleeding from the vagina, either between periods (mistaken as a result of hormonal imbalance) or after sex (mistaken as a result of dryness or infection). In post-menopausal women there can be post menopausal bleeding. Other symptoms include unpleasant-smelling vaginal discharge (mistaken as a result of vaginal infections) and pain during sex (mistaken as a result of dryness). If you have any of these symptoms it is important that you visit your gynaecologist. There may also be non-specific symptoms like loss of appetite, weight loss, heavy menses, pelvic pain, back pain, leg pain and fatigue for example.


5. Diagnosis of Cervical Cancer (i.e. Pelvic exam, Pap smear test, vaccine?)
Routine pap smears are still the most common method for detecting cervical cancer. It accurately detects 90% of cervical cancers, even before symptoms develop. A colposcopy and biopsy is another method and is usually performed following an abnormal pap smear. This provides a magnified view of the abnormal cervix. In this minor procedure, acetic acid and iodine is applied to the cervix to highlight the abnormal areas and biopsies of the abnormal areas are then taken for further evaluation.


6. Types of Treatment
The treatment for cervical cancer really depends on the stage of the cancer. Early stage disease equates to better prognosis and survival. For early stage invasive cancer, surgery is the treatment of choice followed by maybe radiotherapy and chemotherapy. In more advanced disease, radiation combined with chemotherapy is commonly employed. In patients with disseminated disease, chemotherapy or radiation provides the best symptom palliation as the chance of a curative treatment is low.

Disclaimer: The information in this website is for general health education only. Please consult a doctor if you have symptoms or questions on medical conditions or illnesses.

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