It feels as though we need a good news story at the moment. And I was reading recently about the incredible success of the Human papillomavirus (HPV) vaccine. It really is yet another amazing example of the power of science. HPV is a large group of viruses that are common in humans but normally do not cause any problems. A small number of them though can lead to cancers and are deemed “high risk”. Harald zur Hausen isolated HPV strains in cervical cancer tumours back in the 1980s and theorised that the cancer was caused by HPV. This was subsequently proved right: in fact we now think 99.7% of cervical cancers are caused by persistent HPV infection. This understanding along with vaccine technology led to the development of these amazing vaccines, which are incredibly as much as 99% effective against the high risk virus strains. And the results speak for themselves, as you can see in the graphic above. This shows the percentage of women at age 20 diagnosed with cervical cancer by birth year and that the numbers have dropped dramatically as the vaccination rates have increased. zur Hausen won the Nobel Prize for medicine for his fundamental work that has impacted human health to such a degree.
What had me intrigued particularly about this story is that here in the UK, there has been public concern that the frequency of testing for cervical cancer (via the “smear test”) is being reduced – in Wales specifically. The concern is that this is about reducing the cost of the screening programme. The reason the frequency is being reduced from 3 to 5 years is scientifically supported however, because the test has changed. In the past, the test involved taking a smear and then looking for cancerous cells through a microscope. This test had various problems. First, the smear may not have come from a cancerous part of the cervix. Second, as it involves a human looking through a microscope, they might miss seeing a cancerous cell in the early stages.
The new test, though, looks for the high risk HPV strains. If there is HPV present, it will be throughout the cervix and so will be detected regardless of where the test is from. And it doesn’t involve a human looking through a microscope. But there is an added, huge, benefit. Detecting the high risk HPV strain doesn’t mean there is cancer – it is a risk factor. And so further screening can take place if this test is positive. This means that cancer can be detected at an earlier stage. Because the new test is so much better, and gives an earlier detection, there is more time to act. Cervical cancer normally develops slowly.
In Risk-Based Quality Management (RBQM) in clinical trials, we identify risks, evaluate them, and then try to reduce the highest risks to the success of the trial (in terms of patient safety and the integrity of the trial results). One way to reduce a risk is to put a measurement in place. People I work with often struggle with understanding how to assess the effectiveness of a risk measurement but I think this cervical cancer testing gives an excellent example. The existing test (with the microscope) can detect the early stages of cancer. But the newer test can actually detect the risk of a cancer – it is earlier in the development cycle of the cancer. The newer test detects with more time to act. And because of that, the test frequency is being reduced. The best measurements for risk provide plenty of time to take action in order to reduce the impact – in this case, cervical cancer.
This example also demonstrates another point. That understanding the process (the cause and effect) means that you can control the process better. In this case by both eliminating the cause (via the HPV vaccine) and improving the measurement of the risk of cancer (via the test for high risk HPV strains). Process improvement always starts with process understanding.
Vaccines have been in our minds rather more than usual over the last couple of years. It is sobering to think of the number of lives they have saved since their discovery in 1796 by Edward Jenner.
Text: © 2022 Dorricott MPI Ltd. All rights reserved.
Image – Vaccine Knowledge Project https://vk.ovg.ox.ac.uk/vk/hpv-vaccine