Counselling
Cervical cancer can be prevented
01/SEP/08
The appearance in the pharmaceutical market of a Tetravalent Vaccine for the prevention of High Grade Cervical Dysplasia, Cervical Cancer and Genital Warts causally related to virus types 6, 11, 16 and 18 of HPV (Human Papillomavirus), requires gynaecologists to carry out a series of considerations for information purposes.
1. Epidemiologic studies show that the Human Papillomavirus is the agent that causes cervical cancer and that certain types of HPV - High Grade types - are found in practically all cervical cancer cases.
2. Cervical cancer is the second most frequent cancer in women throughout the world. 93% of the cases represent 15% of female cancer. In general, the lowest rates are found in Europe with less than 15% per 100,000 and the highest in east Africa with 42% and the Caribbean with 33%. In Spain, the rate varies between 3.4% in Cuenca and 12% in Majorca. This data has been taken from the Tumour Register.
3. So far more than 100 types of papillomavirus have been identified, of which 40 are usually found in the genital tract. 15 of these 40 are related to cervical cancer and are classified according to their carcinogenic risk: low or high. The most significant aspect is the prevalence of these infections, given that 70% of women with an active sex life have had some contact with HPV. In around 85% of cases the women’s immune systems have managed to make the virus disappear and only around 15% are persistent cases. Types 16 and 18 are the most carcinogenic as they are highly persistent.
4. Therefore, in order to establish the progression of the disease the infection need to be prevalent and this depends, in addition to the type of virus and its viral load, on a series of cofactors that foster prevalence and therefore cervical cancer:
- Immunological and genetic factors.
- Starting sexual relations at a young age with a major increase in the number of lovers or having sexual relations with promiscuous males.
- Tobacco consumption.
- Having had sexually transmitted diseases in the past (chlamydia, herpes, etc.).
- Multiparity.
- Consumption of anovulants for more than 10 years.
- Food and socio-economic factors. The consumption of fruit and vegetables seems to reduce the risk.
Conclusions
For primary prevention of cervical cancer it is advisable to avoid sexually transmitted diseases by using condoms, avoiding starting to be sexually active at a young age, avoiding promiscuity, not smoking, improving diet, etc. Special care needs to taken in states of low immunity.
Vaccine?
The recently launched vaccine is mainly indicated for girls aged between 9 and 14, before they start to be sexually active, in a prepubescent phase in which there is a greater immunological response as more neutralising antibodies are produced.
Furthermore, it is indicated for women up to the age of 26, although all women that have started to be sexually active may benefit from it. It is advisable for women to undergo a virus typing test in order to exclude HPV contamination.
This vaccine protects against types 16 and 18, which are the most frequent types and present in 78% of all cervical cancers. It does not protect against all types and we do not know the duration of the immunity and whether a booster may be required some years later. It must be taken into account that in women natural infections maintain antibodies for more than 10 years and that a vaccine is 80 times more powerful with regard to the production of antibodies, so in the worst case scenario, women will be immune for the period of most risk. Furthermore, there is talk of crossed protection with regard to other types of HPV. In view of the above, I am in favour of the use of the vaccine as it radically reduces the incidence of cervical cancer. The fact that we think that a booster may be required some years later or that new vaccines covering more types may be produced in the future does not invalidate this.
The vaccine will not replace cervical screening. What it will do is reduce its frequency of repetition to once every 4 or 5 years and make it unnecessary for vaccinated women to start screening before the age of 30.
Nevertheless, women should consult their gynaecologists for more detailed and personalised information in this regard. Vaccination should not replace periodical gynaecological check-ups.
