[Top: Picture of Cervarix, one of the two cervical cancer vaccines approved for use in Singapore.]
By Prof Tay Eng Hseon
At least half of all sexually active women will get an HPV infection at some point in their life - is this true? Why are HPV infections so common?
Every sexually active man and woman is at risk of human papilloma virus (HPV) infection. HPV is transmitted through skin-to-skin contact. About 50 per cent of women will acquire an HPV infection in their lifetime and condom usage may not adequately protect them from HPV. But only about 10 to 20 per cent of women are infected by the cancer-causing high-risk types of HPV (HPV types 16 and 18). Most are relatively harmless, and usually do not cause symptoms and go away on their own. On the other hand, genital warts are caused by HPV types 6 and 11 and do not lead to cancer.
It is only with persistent HPV infection that cervical cancer may develop. The infection is contained in the skin of the cervix and in most cases, our body is able to get rid of this virus through our immune system. But there are many women who are not able to do this and with persistent infection, the skin of the cervix develops into pre-cancer and cancer.
The best preventive measures are HPV vaccination and early detection through Pap smear screening.
Are there warning signs of HPV infection?
Most HPV infections have no signs or symptoms. The virus can be transmitted even when no symptoms or visible signs are present.
Are there early warning signs of cervical cancer?
There are no early warning signs for the very early stages of cervical cancer. Symptoms normally appear at a much later stage when a tumour has developed on the cervix. These could include vaginal bleeding after intercourse, between periods or after menopause; watery, bloody vaginal discharge that may be heavy and have a foul odour; and pelvic pain or pain during intercourse.
More than one case of cervical cancer is diagnosed in Singapore every two days. Every five days, a woman dies of cervical cancer.
Hence, it is crucial for women to get vaccinated and undergo regular Pap smear screening.
Are there factors that make a woman more vulnerable to cervical cancer? If so, what are they?
All women are at risk, but co-factors like smoking and a weakened immune system (for e.g., a patient with autoimmune disease) promote cancer formation.
I read that having sex before 18 increases the risk of HPV infection. Is this true?
A possible explanation is the greater vulnerability of the cervical tissues at the younger age to the carcinogenic effects of high-risk HPVs. Another explanation could be that girls who become sexually exposed at a very young age are likely to have more sexual partners during their life-time, hence increasing their chances of coming in contact with the cancer-causing types of HPVs.
What are the treatment options for cervical cancer, and what are the chances of survival?
They are surgery to remove the cervix and/or uterus, and radiation treatment either with or without chemotherapy.
If detected in the earliest stage – the cure rate is close to 100 per cent. The survival falls rapidly with increasing stages and becomes incurable in Stage IV. Unfortunately, the overall survival rate for women with cervical cancer in Singapore is only about 60 per cent because many women still do not go for screening and present themselves early for treatment.
How does this cancer impact a women's ability in future to conceive?
A woman may lose her womb through surgery. Radiation treatment also destroys the function of the womb making it unable to carry a pregnancy. A standard field radiation therapy will definitely destroy the function of the uterus. The women are normally rendered menopausal following full treatment.
I heard the take-up rate of cervical cancer vaccination is low. Why?
Less than 1 per cent of women or about 6,600 of 1,807,000 women in Singapore go for cervical cancer vaccination.
A full course of vaccination cost about $600. We seldom get a chance to prevent a cancer by vaccination. The only other example is the Hepatitis B vaccine, which reduces the risk of liver cancer.
Given its potential to prevent cancer and save a life, the cost of cancer treatment, and the cost of researching on and producing the vaccines, this amount for cervical cancer vaccination is reasonable. Of course, if the cost can be reduced, it will facilitate greater take-up of the vaccines.
-Answers provided by Assoc Prof Tay Eng Hseon, Medical Director of Thomson Women's Cancer Centre at Novena Medical Centre and Senior Consultant Gynaecologist at Thomson Medical Centre
