Recent advances in cervical cancer prevention mean that controlling the disease in developing countries is becoming feasible for the first time, experts say.
Developments such as highly effective vaccines against the human papilloma virus (HPV) and promising new screening tests provide an unprecedented opportunity to tackle the disease in poor countries, where pap smear screening has largely failed because it is too expensive and too complicated to implement, the experts said in a series of papers on the topic unveiled Thursday at the World Cancer Congress of the International Union Against Cancer in Geneva.
The papers are contained in a monograph published in the journal Vaccine. They present the best global thinking on cervical cancer prevention with vaccination and screening, as well as fresh regional and national research and insights to guide governments and donors in building plans. An independent collaboration of more than 180 leading experts, the monograph evaluates which strategies are most promising and likely to be most cost-effective and affordable and sets out various scenarios for programmes.
Every year, about 500,000 women worldwide are diagnosed with cervical cancer and more than 250,000 die from the disease. It is the leading cancer in women in half the countries of the world and mostly affects relatively young poor women. About 80%of cervical cancer deaths occur in developing countries.
"Recent estimates indicate that if trends continue the way they are, developing countries will face a 75% increase in the number of cervical cancer cases because of growth and aging of the population in the next two decades. But it doesn't have to turn out that way," said the coordinator of the monograph, Professor Francesc Xavier Bosch of the Catalan Institute of Oncology in Barcelona, Spain. "The discovery of HPV as the cause of cervical cancer has shaken a field that was stagnating and we are now in a new era where developing countries no longer have to be left behind."
The monograph presents the first broad analysis of the cost-effectiveness of introducing HPV vaccination and new screening methods into the hardest hit regions of the world - Asia-Pacific, Latin America and the Caribbean. The benefits varied, depending on the size and make-up of the population and the burden of cervical cancer in each country. Future monographs will address the situation in Africa, the Middle East and Eastern Europe.
The experts determined that in the Asia-Pacific region, which accounts for more than half of the world's cervical cancer cases, vaccination would be cost-effective - even in the poorest countries - if the cost per vaccinated girl was between $10-$25. For Latin America and the Caribbean, the cost per vaccinated girl, including delivery and logistics costs, would have to be less than $25 to be cost-effective for all countries. In the most developed populations in the region, vaccination would be cost-saving if the cost per vaccinated girl is between $25 and $60, and cost-effective at higher prices.
"Efforts are needed now to adapt the current price of the vaccines so they meet what individual countries can afford; the solution may be tiered pricing according to gross national income per capita and according to the scale of country efforts," Bosh said. Currently the vaccine's price in the private sector is about $120 per dose, or $360 per vaccinated girl. Many countries will need subsidies for some time."
The monograph also presents updated evidence on the efficacy of various new screening alternatives and how they compare to pap smear testing, as well as a discussion of innovative funding mechanisms for bringing HPV vaccination to poor countries, such as the sale of highly-rated vaccine bonds to investors.
New screening methods that are increasingly proving themselves in pilot studies provide viable alternatives to pap smears for the first time, the experts said. One such method, known as visual inspection with acetic acid, or VIA, involves painting the cervix with vinegar. It is an attractive alternative because it is cheap, seems to be very effective in detecting pre-cancerous lesions, entails only one visit and a simpler treatment that can be performed by nurses immediately and is less dependent on having a strong health infrastructure. A recent large study in India showed a significant reduction in cervical cancer cases and deaths in areas using VIA.
Testing for HPV DNA is also a recent screening advance considered important for the developing world, especially as new rapid test kits being developed especially for poor countries are expected to be cheaper and easier to use. Studies have consistently shown that HPV testing works better than pap smears as the primary screening test because it is better at picking up suspicious cases.
"The models provide a useful roadmap for testing promising strategies in the field. More research is needed to determine an efficient combination of these new approaches and each country will have to decide which is best for them, but we are confident we have provided a valuable starting point for going forward," Bosch said.