A few weeks ago I wrote an article about Emma Mhic Mhathúna was a 37-year-old Irish mother of five who died in October 2018 from cervical cancer – an easily diagnosed and treated cancer if discovered early. She died because of a pap smear scandal in Ireland that led her to receive a false negative on her two pap smear tests in 2016. As a result of this scandal, HPV vaccine uptake has increased for preventing cervical cancer.
Preventing cervical cancer primer
The most important risk factor for cervical cancer is an infection by the sexually-transmitted human papillomavirus (HPV). There are at least 147 strains or subtypes of HPV that can infect humans – however, only 40 of these strains are linked to one or more different cancers. Of those 40 strains, most are fairly rare – HPV types 16 and 18 are, by far, the most common types linked to cervical cancer.
The virus causes over 43,000 cancers a year in the USA, including, according to the CDC, nearly 12,000 cervical cancers every year.
One of the best methods to detect and identify the type of cervical cancer, the Pap test, is named after the inventors, doctors Georgios Papanikolaou and Aurel Babeș. It is also known as the Pap smear, cervical smear, cervical screening, or smear test (depending on where you live in the world).
The test is used to screen cervical cells to detect potentially pre-cancerous and cancerous cells in the cervix, the opening of the uterus. If these cells are found, the woman is usually directed to follow up with more diagnostic procedures to eliminate false positives or proceed with the treatment of cervical cancer.
The cervical smear test, when combined with appropriate follow-up, can reduce cervical cancer deaths by up to 80%. As opposed to the claims made by way too many adherents of the anti-vaccine religion, the Pap smear is not even close to a perfect strategy for preventing cervical cancer.
The Irish Pap smear scandal
In 2008, the Irish HSE began CervicalCheck,“a quality-assured, organised and population-based screening programme” to provide free cervical screening to women aged 25 to 60. The CervicalCheck women’s charter says the service is “committed to providing a safe and reliable service to women.”
In 2008, the HSE awarded a contract to Quest Diagnostics to examine the tests followed by a 2010 contract to Clinical Pathology Laboratories. A hospital in Dublin also was involved in the testing but lacked the ability to process so many tests at one time.
Here’s where the problem started. According to Dr. David Gibbons, the former chair of the cytology/histology group within the quality assurance committee of the National Cervical Screening Programme, argued that US labs have a 1/3 lower detection rate for abnormal cells than those in Ireland. Although this is horrific for over 200 Irish women who may have received false negatives, think about what this means for women in the USA. There are hundreds or thousands more tests done on American women (as a result of a substantially larger population) – this could mean thousands of American women who have false positives.
Dr. Gibbons resigned in April 2018 because his findings were ignored.
Pap smears are much more subjective than many other diagnostic tests for cancers, despite the test’s importance in preventing cervical cancer. The cells from the Pap smear must be examined under a microscope by a technician. Or an image from the microscope is sent to an offsite (or even offshore) group of technicians to review those images.
And the results from those analyses are influenced by everything from fatigue to incompetence to bad images. What really matters, however, is that false negatives can lead to a woman’s false relief from a cervical cancer diagnosis. What began as a noble and important plan for an important women’s health issue ended up being a disaster.
As a result of this Pap smear scandal, Ms. Mhathúna sued the HSE and the US clinical laboratory, Quest Diagnostics, which performed the tests. She settled in court for €7.5 million from HSE and Quest. Another US-based clinical laboratory, Clinical Pathology Laboratories (CPL) of Austin, TX, was involved in a similar lawsuit from another Irish woman, Vicky Phelan, who also received a false negative – they settled with for €2.5 million.
Increased HPV vaccine uptake for preventing cervical cancer
By 2014-15, HPV vaccine uptake in Ireland had hit 87% for girls 12-13, when the vaccine is recommended. This was an impressive number, far exceeding the HPV vaccine uptake in the USA which hovers around 50% as recently as 2017.
As a result of the unfortunate, and easily debunked, myths and tropes from the anti-vaxxers about Gardasil, HPV vaccine coverage dropped to around 51% in Ireland by 2016. Let’s be clear – this drop in uptake did not result from the cost of the vaccine that caused this drop (it’s free for Irish teens). It was caused by the lies and misinformation about the vaccine pushed by vaccine deniers that have flooded the internet.
The Irish Pap smear scandal has caused Irish parents to re-evaluate the HPV vaccine – coverage increased from 51% to 63% in 2017. Although we don’t have evidence as to the reasons for the increase, it’s certainly partially related to the realization that Pap smears are overrated as a method for preventing cervical cancer.
Preventing cervical cancer is the best choice
Still, I never understood the argument that the Pap smear was more important than the HPV vaccine. It’s like saying that it’s OK to smoke cigarettes because we can detect lung cancer. Preventing cervical cancer with the HPV vaccine is so much better and easier than getting diagnosed for it with the Pap smear. And preventing lung cancer by quitting smoking is so much better and easier than getting diagnosed with lung cancer.
The narrative pushed by the anti-vaccine religion is that the HPV vaccine is worthless because cervical smears catch “most” cervical cancers early. First, most HPV-related cancers are not cervical cancer, the HPV vaccine prevents those cancers. Second, this narrative wrongly assumes that getting an early diagnosis of a potential cancer is somehow comforting. It’s not. It’s more important to prevent cancer than to get a diagnosis – anyone who has had a cancer diagnosis would embrace that without too much thought.
And given the weakness of the Pap smear in catching all cervical cancers, the anti-vaccine fake facts about the uselessness of the HPV vaccine falls right on its face.
We have powerful evidence that the HPV vaccine is critical to preventing cervical cancer. Let’s prevent cancer rather than diagnosing it, especially with a flawed testing method.
Citations
- Arbyn M, Anttila A, Jordan J, Ronco G, Schenck U, Segnan N, Wiener H, Herbert A, von Karsa L. European Guidelines for Quality Assurance in Cervical Cancer Screening. Second edition–summary document. Ann Oncol. 2010 Mar;21(3):448-58. doi: 10.1093/annonc/mdp471. PubMed PMID: 20176693; PubMed Central PMCID: PMC2826099.
- Van Dyne EA, Henley SJ, Saraiya M, Thomas CC, Markowitz LE, Benard VB. Trends in Human Papillomavirus-Associated Cancers – United States, 1999-2015. MMWR Morb Mortal Wkly Rep. 2018 Aug 24;67(33):918-924. doi: 10.15585/mmwr.mm6733a2. PubMed PMID: 30138307.
