A test for cervical cancer has a 100 percent success rate, significantly beating out the tests we currently use like the Pap smear and HPV test.
HPV, aka the human papillomavirus, is responsible for the vast majority of cervical cancer cases worldwide. There are over 100 different types of HPV, a small handful of which are known to cause cancer. It is mainly transmitted through sexual activity.
The current HPV test detects the presence of the virus rather than actual cancer risk. HPV often doesn't cause any problems, so many women who test positive in an HPV test undergo unnecessary stress. The Pap smear involves taking a sample of cells from the cervix and examining them under a microscope. Neither test is 100 percent effective.
So a team of researchers, led by Queen Mary University of London, developed a new test and conducted a randomized clinical trial of 15,744 women aged 25 to 65 in Canada to see how well it worked. It spotted all eight of the invasive cervical cancers that developed in the women, while the Pap smear only detected a quarter of the cancers, and the HPV test detected half.
Therefore, the new test is a significant step in the right direction when it comes to catching cancer early. The findings are published in the International Journal of Cancer.
“This is an enormous development. We’re not only astounded by how well this test detects cervical cancer, but it is the first time that anyone has proven the key role of epigenetics in the development of a major solid cancer using data from patients in the clinic,” said lead researcher Professor Attila Lorincz in a statement. “Epigenetic changes are what this cervical cancer test picks up and is exactly why it works so well.”
Epigenetics refers to how genes are expressed, i.e. whether specific genes are turned "on" or "off", rather than changes to the genetic code itself. Professor Lorincz told IFLScience that the new test detects changes in both the HPV and the patient, making it a "combined classifier" and enhancing its performance.
“In contrast to what most researchers and clinicians are saying, we are seeing more and more evidence that it is in fact epigenetics, and not DNA mutations, that drives a whole range of early cancers, including cervical, anal, oropharyngeal, colon, and prostate,” he said in the statement.
The team also looked at 257 HPV-positive women selected from their larger cohort. The new test managed to detect 93 percent of pre-cancerous lesions. A combination of the Pap smear and HPV test had an 86 percent success rate, while the Pap smear alone only detected the lesions 61 percent of the time.
It’s important to note that the test will likely take about five years to become an established method that’s used in clinics and hospitals. Nevertheless, it could have a significant positive impact in the future.
“This really is a huge advance in how to deal with HPV-infected women and men, numbering in the billions worldwide, and it is going to revolutionise screening,” said Lorincz.