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World Cancer Day 2017: how to prevent cervical cancer cases around the globe

Category: Science blog February 8, 2017 Emma Smith 3 comments

In the second part of our World Cancer Day series, we take a look at cervical cancer rates in different parts of the world. Explore the map below to see how these rates vary, and read on to find out what can be done to prevent the disease in the future.

There are more than 3000 new cases of cervical cancer diagnosed in the UK each year, making it the 13th most common cancer in women.

But worldwide it’s a different picture. Cervical cancer is the 4th most common cancer in women based on global stats, with more than 527,000 new cases being diagnosed every year (8% of all female cancer cases). It claims more than 265,000 lives a year.

But the impact of the disease is not shared equally around the world.

More than 8 in 10 cervical cancer deaths (85%) are in low- to middle-income countries. As shown in the map above, women living in Africa, South America, and parts of Asia are hardest hit by this inequality.

This largely reflects the lack of cervical screening programmes in these countries. Despite its huge success in the UK and other developed countries, accessible and effective cervical screening isn’t available everywhere. And it means hundreds of thousands of women are dying from what is mostly a preventable cancer.

An ounce of prevention is worth a pound of cure

Nearly all cervical cancers have a single, known cause: a virus. Thanks to the work of Professor Harald zur Hausen and research following his discovery, it’s known that persistent infection with high risk types of the human papillomavirus (HPV) can cause genetic changes in cervical cells that sometimes lead to cancer (something we’ve covered in detail before).

Crucially, this discovery has led to effective ways to prevent the disease. In 2007, Australia became the first country to roll out a national HPV vaccination programme. The UK followed suit in 2008, offering school girls vaccinations to protect them from infection with two high risk HPV types (HPV16 and HPV18), which between them cause 7 in 10 cases of cervical cancer.

By mid-2016, 65 countries had introduced HPV vaccination programmes. Most of these are developed countries, but the list includes an increasing number of middle- and low-income countries.

But decades before the vaccine was available, researchers had developed another way to protect women from cervical cancer: cervical screening.

The UK’s national cervical screening programme was introduced in 1988. It’s largely thanks to the screening programme that the rates of cervical cancer have decreased by 44% in the UK since the late 1970s, saving thousands of lives from the disease each year. And similar screening programmes are offered to women in other developed countries around the world, helping cut the number of women getting cervical cancer in these countries too.

So why isn’t cervical screening available everywhere?

The hold up

For low-income countries there are large financial and practical barriers to setting up an effective national cervical screening programme.

Most cervical screening programmes aim to detect early changes in cells before those cells become cancer, and require trained staff to carry out the screening test and any follow up tests needed (such as a colposcopy). They also require specialists to examine any samples of cells removed from the cervix.

For women who choose to take part in screening in the UK, it means making an appointment for a cervical screening test when they receive an invitation through the post, plus extra visits to see doctors if results come back abnormal.

But the situation in Somalia, for example, is very different.

There’s poor access to free healthcare and the nearest affordable hospital can be many miles away with little means of transport. If you make it to a hospital the queues there are likely to be long and the facilities are often poorly equipped and lack trained staff. Many women simply can’t afford to lose a day’s income, and for those who can, the whole trip would be futile anyway as there aren’t any trained specialists to examine the sample; not a single one in the whole country.

And this is a story that’s told time and time again in many low-income countries.

The cervical screening programme that works so effectively in the UK  ̶  preventing thousands of cervical cancer cases and deaths – is simply not feasible in these locations.

So scientists are looking for cheaper and more practical alternatives, such as using rapid HPV testing kits and improving visual inspection of the cervix to spot patches of abnormal cells.

But until all countries are able to offer vaccination against HPV as well as cervical screening, women will continue to die from an almost entirely preventable disease.

Why are women still dying in developed countries?

National cervical screening programmes work, so why do developed countries still see cases of cervical cancer?

No test is 100% perfect. Screening can sometimes miss abnormal cells, and some women may develop cancer between screens. And as screening is usually only offered to women between certain ages based on evidence of how the benefits and harms stack up (in the UK it’s offered to women aged 25 to 64), there are some cases where women who aren’t in this age bracket for screening might develop cancer.

But the main reason that women develop cervical cancer in countries with a screening programme is that they don’t participate.

Dr Jo Waller, a Cancer Research UK scientist at the UCL Department of Behavioural Science and Health, carries out research into people’s reasons for not taking up the invitation for cervical screening.

Dr Jo Waller

And she says there are 4 main groups of people who don’t attend.

“The first group isn’t aware of the programme. This is particularly a problem for women whose first language isn’t English – they might not understand the invite.

“The second group is aware, but choose not to go. The third group intend to go, but for various practical reasons they don’t actually attend an appointment. And lastly, there is a group of women who have attended a screening appointment but don’t wish to go again – maybe due to a bad experience.”

In some ways, says Waller, cervical screening might be a victim of its own success.

“Because it works so well and cervical cancer isn’t common in women in the UK, some people don’t see the point of attending screening because they perceive cervical cancer as a low risk,” she says.

The next steps are to use this information to help tackle some of these barriers. Some are fairly straightforward, like making sure everyone who’s eligible for screening receives information they can understand.

Wherever they live in the world, we’d like to see all women being able to make an informed choice about cervical screening, having access to it, and having minimal barriers getting in the way if they want to participate

– Dr Jo Waller

Waller’s team is also carrying out research into ways to raise awareness of screening and address any misconceptions around the test. They are also looking into cultural barriers that may put some women off, like whether male staff in clinics may be an issue and if attending screening is difficult for some women because it conveys the message that they’re sexually active.

Another interesting study is testing whether women would find a home testing kit acceptable so they could collect a sample at home. This test, which already exists, could identify women infected with high-risk types of HPV, who are at higher risk of developing cervical cancer. “This could help address some of the practical barriers to going to the GP for a screening test,” says Waller. “And it overcomes limited access to healthcare too, so it could be useful in low to middle-income countries as well.”

Although screening is a very effective way to prevent cervical cancer, not every woman will want to take part, and their views need to be respected. But there are still things that need to be done to reach the ideal situation.

“Wherever they live in the world, we’d like to see all women being able to make an informed choice about cervical screening, having access to it, and having minimal barriers getting in the way if they want to participate,” Waller says.

And for low-income countries without effective screening programmes, and high cervical cancer rates, the healthcare system is a long way from that goal.

Emma