How to prevent cervical cancer: Vaccinate early and go for follow-up screenings

For cervical cancer, human papilloma virus (HPV) is now considered the primary etiological agent. Nevertheless, HPV infection is often intermittent and ultimately, only a small number of women with chronic infection develop cervical cancer. Behavioural and lifestyle variables, as well as sexually transmitted infections such as bacterial-vaginosis, Chlamydia trachomatis, HSV and HIV have been identified as potential co-factors in cervical cancer.

WHAT ARE RISK FACTORS?

These include long-term use of oral contraceptives, high parity, low socio-economic status, smoking, HIV co-infection, sexual debut at a young age, teenage pregnancy, multiple sexual partners, a shorter inter-pregnancy interval and sexually transmitted infection (STI).

WHAT ABOUT PREVENTION MEASURES?

The World Health Assembly adopted a global strategy to accelerate the elimination of cervical cancer by 2030. Targets have been set to accelerate the process of elimination. The 90–70–90 targets are set which are supposed to be achieved by the countries striving for cervical cancer elimination. This means the following:

•Approximately 90 per cent of girls to be completely vaccinated with the HPV vaccine by the age of 15 years.

• Approximately 70 per cent of women to be screened by the age of 35 years, and undergo repeat screening by 45.

• Approximately 90 per cent of women suffering from cancer (pre-invasive and invasive disease) to be identified and treated

• As a result, a target of 4 per 100,000 women every year can be achieved as a part of the cervical cancer elimination goal.

WHAT ARE VACCINATION OPTIONS?

Among women never infected with HPV, the vaccination causes prevention of cancer in almost 100 per cent of cases. Vaccines which protect against HPV 16 and 18 also have cross-protection against other less-common high-risk HPV-types. WHO considers all three vaccines equally protective against onset.

In women with a normal immune system, it may take 15 to 20 years to develop cancer in case the infection with high-risk is persistent. But in women with immune-compromise, it may take only 5-10 years to develop the cancer. Girls, who start the vaccination between 9 and 14 years, need only two doses at intervals of six months. Teens, who start the vaccination after 15 years, need three doses of the vaccine. The girls, who are immune-compromised, also need three doses. The schedule for three doses is 0, 2 and 6 months. The best is to give the vaccination before sexual debut. But in case the women are already exposed and are sexually active, the vaccine will protect them against strains to which they have not been exposed. Most women contract HPV infections within five years of becoming sexually active. HPV vaccines do not treat HPV infections.

India now has its own vaccine being developed by the Serum Institute of India. This is a quadrivalent vaccine, meaning it protects against the four most common strains of the virus known to cause cancers HPV 16, 18, 6, and 11.

The three HPV-vaccines, which are available, approved by the US FDA and recommended by CDC, include:

• Bivalent-vaccine (Cervarix) can be given to women up to 45 years

• Quadrivalent-vaccine (Gardasil) can be given up to 45 years

• Quadrivalent-vaccine has the capacity to protect against HPV 16,18 together with HPV types 6 and 11
• It is licensed for use in men.

COMMON SIDE EFFECTS

• Pain over the injection site

• Fever

• Dizziness

• Nausea

• Fainting attacks (Sitting or lying down for 15 minutes precautionary).

This vaccine is not recommended during pregnancy. In case a woman gets the first dose of the vaccine and then gets pregnant, then she should postpone the remaining doses till after delivery. No need for MTP if the patient takes the vaccine during ongoing pregnancy. This vaccination is safe during lactation. Women can be given this vaccine in the post-partum period.

Women vaccinated with HPV vaccine still need to be screened by Pap Smear or by LBC or by primary HPV-DNA testing periodically as per local guidelines.

HPV vaccination and regular cervical screening are the most effective ways to prevent cervical cancer. Parents/caregivers of children must be educated about HPV vaccination. We need to start early to reduce the risk of developing cancer considerably.