DOI: https://doi.org/10.20529/IJME.2010.016
Cervical cancer is the most common cancer among women in the less developed countries which account for 80% of the global burden of the disease and over 80% of the global mortality due to cervical cancer. Latin America and the Asia-Pacific region account for about 60% of cervical cancer cases worldwide. An estimated 2,05,496 new cases and 1,19,097 deaths due to cervical cancer will occur in India by 2020, contributing to 29% and 30% respectively of the global burden of cervical cancer cases and mortality (1).
The human papilloma virus (HPV) as a causative agent for cervical cancer was first proposed in the 1970s and was soon shown to be the primary etiology of the disease (2, 3, 4). Several studies later established that all cervical cancers were the outcome of a process that was initiated by infections due to a specific group of high-risk human papilloma viruses (5, 6, 7, 8, 9, 10)
Randomised controlled studies suggest that VIA (Visual Inspection with Acetic Acid) is an attractive alternative to Pap smear screening (11, 12, 13). A recently published report from India indicates that screening women once in their lifetime at the age of 35 with HPV DNA testing reduced the lifetime risk of cervical cancer by up to 36%, at a cost of less than $500 per life saved (14). Low cost HPV tests that would provide quality results within one working day and would allow for screen-and-treat protocols have been recently tried in China (15). When available, these tests would help reduce the costs of the cervical screening programmes significantly worldwide, making them sustainable even in the less developed countries.
HPV vaccines are certainly a major breakthrough in the primary prevention strategies for cervical cancer and vaccine trials till date have shown very good immunogenicity in HPV-naive girls and have been reported to be generally safe. The currently licensed HPV vaccines – quadrivalent HPV 16, 18, 6, 11(Gardasil(r), Merck &; Co., Inc., Whitehouse Station, NJ USA) and bivalent HPV 16, 18 (Cervarix(tm), GlaxoSmithKline Biologicals, Rixensart, Belgium) – contain virus-like particles and are expected to prevent an estimated 70% of cervical cancers. Immunisation of young women with virus-like particles of oncogenic HPV types 16 and 18 has been shown to confer almost 100% protection against infection and disease related to these virus types (16, 17, 18, 19, 20, 21, 22, 23).
Vaccine pricing, cost of vaccine delivery to the eligible population, eligible population coverage, long term sustainability and cultural acceptability should be the driving variables in the adoption of any population-based vaccination programme. The HPV vaccines currently available have not been proven to be therapeutic, necessitating the identification of very young pre-pubertal girls who are likely to be HPV naive for vaccination. This is likely to raise cultural and ethical issues. Besides the final proof of vaccine efficacy – reduction in cervical cancer mortality – is yet to be proven and might take another 10-15 years to be conclusively demonstrated.
Reviewing countrywide HPV vaccination strategies in the above context, I would advise a limited number of pilot programmes that study, in depth, vaccine efficacy, safety, acceptability and sustainability in girls of different age groups in a variety of population groups across the country. Such data and the evidence therein, when available in the next four to five years, should form the basis of future national policies on the subject.