The research that saves thousands of women every year

It is one of the great successes in the world of cancer research: in just 30 years, a virus has been identified as the cause of a type of cancer and a vaccine has been developed that effectively prevents the disease. Professor Susanne Krüger Kj?r has been leading the way.

-?????? I have researched HPV my entire career. And it is the strongest risk factor for the development of cancer that I have seen. In all studies, we see the same sure connection between HPV and the risk of cervical cancer. Popularly speaking: No HPV – no cervical cancer.

This is what one of the world's leading experts in HPV and cervical cancer, Professor Susanne Krüger Kj?r, says about the HPV vaccine. Over the her the effect of which she has documented in her research, and will prevent thousands of cancer cases in the future.

HPV causes cervical cancer

HPV is the cause of nearly 700,000 cases of cancer worldwide each year. More than 550,000 of them are cervical cancer.

But thanks to research, it seems that within the foreseeable future we in the Western world will have the same relationship with HPV-related cervical cancer as we do today with measles and smallpox: It will be a disease that we know the name of, but to which we otherwise do not give so much thought.

In 1984, the young doctor Susanne Krüger Kj?r was employed as a scientific assistant at the Danish Cancer Institute in Copenhagen, alongside her clinical work as a doctor.

-?????? I wanted to specialise in gynaecology, and that required research experience on my CV. My boss gave me free rein to choose an area. I had heard a little about HPV and about zur Hausen's work and thought it sounded interesting. So I took the plunge, says Susanne Krüger Kj?r.

Today, 40 years on, Susanne Krüger Kj?r is professor of cancer epidemiology, senior physician at Rigshospitalet and research leader at the Danish Cancer Institute. She is one of the world's leading experts in the connection between HPV and cervical cancer and has, among other things, researched the effect of the HPV vaccine.

A vaccine against cancer

The major breakthrough in HPV research came with the German virologist, Professor Harald zur Hausen in 1984. He was the first to describe, among other things, that HPV is present in cancer cells from cervical cancer. He made it probable that a chronic infection with HPV types 16 and 18 in particular could lead to cervical cancer.

Harald zur Hausen's discovery was the start of a journey towards being able to prevent cervical cancer. Because it was a virus, research turned to developing a vaccine to prevent HPV. The basis for this was a colossal amount of research, which provided knowledge that could form the basis for vaccine development, and here Susanne Krüger Kj?r and her research team have put Denmark on the map. Research that was a unique collaboration between researchers from many different disciplines.

One of the first vaccines was the so-called 4-valent HPV vaccine with the name Gardasil. It was designed to protect against four types of HPV, including types 16 and 18, which are responsible for around 70 per cent. of all cervical cancer, as well as types 6 and 11, which cause around 90 per cent. of all genital warts.

The vaccine was tested, among other things, in the so-called FUTURE II trial. Here, around 12,000 girls and women from all over the world were vaccinated from January 2002 to March 2003 with either the vaccine or a placebo. The results were so good that in 2006 Gardasil became the first approved vaccine against HPV.?

In 2009, HPV vaccination was included in the Danish childhood vaccination programme for girls, and there was great support for the new vaccine. Denmark quickly became one of the countries in the world that had the highest support, which in some years was as high as 90 per cent.

Vaccine in the real world

Research is a big part of the process when new drugs like the HPV vaccine are being made. A large part of the research takes place before the remedy is approved, to document that it is safe and effective. But just as important is the research that follows the drug's effect once it has been used. This also applies to the HPV vaccine, where Susanne Krüger Kj?r, not least, has been leading a number of studies that have gathered knowledge about the vaccine after it was approved. Because the use of the vaccine in the real world is less controlled than it is in the clinical trials that precede approval. This is where the vaccine stands its final test.

-?????? We gather knowledge about the vaccine in 'free dressage'. This is where patients may not receive the vaccine doses at the exact recommended interval, perhaps a dose is skipped, and those who receive the vaccine in "real life" may be different from those who choose to participate in the clinical trial trials - for example, they may have other illnesses that would exclude them from participating in the clinical trials at the pharmaceutical companies, says Susanne Krüger Kj?r.

Based on these studies, Susanne Krüger Kj?r and her research team have shown that the incidence of cervical cancer has been reduced by up to 86 per cent. among women vaccinated against HPV before the age of 20 compared to women who are not vaccinated.

-?????? It was fantastic to be involved, together with Sweden, in being the first to document that the vaccine also works on cervical cancer in the real world, Susanne Krüger Kj?r says.

The importance of the HPV vaccine in the real world could also be seen when the statistics on how many women get cervical cancer in Denmark came out in 2023. It showed that the number of women who got cervical cancer decreased. In 2021 274 women got the disease, while the ten years earlier – in 2012 – the number was 367.

The decrease occurred after the HPV vaccine was introduced, and it is precisely the effect of the vaccine that contributes to the fact that we can now see the decrease in cancer numbers, Susanne Krüger Kj?r says.

Next step: Individual screening programme

Today, the HPV vaccine has been thoroughly researched, and its effect is extremely well substantiated. Thanks to the vaccine, thousands will avoid getting cancer in the future.

But the research has the potential to improve our health even more. Because there is such a good effect of vaccination against HPV, screening against cervical cancer will have to be adjusted in the future, according to Susanne Krüger Kj?r.?

In a large implementation study, she and a number of colleagues are already testing screening, where the woman's HPV status determines which examination offers she will subsequently receive, and at what interval. HPV status means an analysis of whether the woman is infected with HPV and, if so, which type(s).

-?????? Whereas today all women aged 23 to 64 are offered a cell scraping every three or five years, I think that in the future we will get a more tailored offer for the individual woman, based on a risk assessment. This will both provide safer screening and at the same time save women from unnecessary examinations, says Susanne Krüger Kj?r.

An incredible journey

For Susanne Krüger Kj?r, her career's focus on HPV and the vaccine has been a fantastic journey:

-?????? It has been a huge gift for me to be involved from start to finish in the work with HPV and the vaccine. Both personally and societal, it is absolutely fantastic that in so few years we have found such an effective prevention against a form of cancer. I also work with other gynaecological cancers, including ovarian cancer, where the progress has not been the same, and where the women still have a low survival rate and risk severe late effects. With cervical cancer, the picture now looks different, and it has been a huge gift to be able to contribute to this, Susanne Krüger Kj?r says.

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