Cervical cancer is an avoidable disease – in theory, at least
Each year more than half a million women worldwide receive a cervical cancer diagnosis but, as the World Health Organization has made clear, the burden of the disease on people and health services is almost entirely avoidable. In principle, at least.
The reason is that nearly all cases of cervical cancer can be traced back to long-term infection with the human papillomavirus (HPV). Prevent the virus from taking hold, using the effective vaccines already on the market as well as screening to catch and treat abnormal cells before they turn into cancer, and rates of the disease can be slashed.
Related: Cervical cancer could be eliminated in England, experts say
HPV is not a single virus. There are more than 100 types, of which more than 40 are spread through all kinds of sexual contact, not just penetrative sex. A couple of types cause genital warts, while a dozen more can cause a range of cancers – head and neck, cervical, penile, anal, vulvar and vaginal among them.
The viruses are incredibly common and most people will pick one up at some point in their lives. But the infections themselves don’t tend to cause symptoms, so people are unlikely to know they have the virus. About 90% clear up on their own within two years.
The vaccines tend to protect against at least two types of HPV, namely HPV 16 and HPV 18, which between them account for about 70% of cervical cancers. Some vaccines prevent infection from more strains, reducing the risk of cervical and other cancers even more. In September last year the NHS brought in routine HPV vaccination for all 12- and 13-year old boys and girls in year 8. The strategy is to protect children before they become sexually active, and so before they are likely to encounter the virus. As they age and protection becomes more widespread, infection rates should plummet.
Hopes for eliminating cervical cancer, or at least reducing cases profoundly, are backed by public health studies, including work by Cancer Council New South Wales. Last year the Australian organisation calculated that high vaccination and screening rates put the country on course to eliminate cervical cancer by 2035, with high-income countries such as the US, UK, Finland and Canada able to reach the same goal between 2055 and 2059.
There is devil in the detail, however. The Australians defined cervical cancer elimination as reducing cases below four per 100,000 women, but that threshold is not universally agreed upon. It is not the most pressing concern, either. What matters more for global public health is broader access to vaccines and screening programmes, particularly in poorer countries where 90% of cervical cancer deaths occur.
In some richer nations such as Ireland, Denmark and Japan, HPV vaccination rates have been dented by unproven concerns over vaccine safety, often fuelled by anti-vaccine campaigns.
