Is this the beginning of the end for cervical cancer?
A recently approved vaccine that could prevent most cervical cancers is causing quite a commotion. In fact, its integration to the universal immunization schedule could greatly reduce the number of women who will suffer from the disease. Thanks to recent technological advances, another revolution in the prevention of cervical cancer is also under way, although much more quietly.
A recently approved vaccine that could prevent most cervical cancers is causing quite a commotion. In fact, its integration to the universal immunization schedule could greatly reduce the number of women who will suffer from the disease. Thanks to recent technological advances, another revolution in the prevention of cervical cancer is also under way, although much more quietly.
Cervical cancer develops from precancerous lesions caused by different types of viruses of the sexually transmitted human papillomavirus (HPV) family. Although these infections are most often benign, they can in some cases, morph into precancerous lesions that can evolve into cervical cancer if they remain untreated.
There are 120 different types of HPV, but not all have carcinogenic powers. The recently approved vaccine targets the two most carcinogenic strains of HPV, reducing the risk of cervical cancer by 70%.
For now however, the Papanicolaou test, commonly called “Pap test”, is the mainstay in the screening of precancerous lesions on the cervix. First, cells are scraped from the surface of the cervix during a gynaecological exam, then are spread onto a slide and studied under a microscope. Since the introduction of the Pap test over 25 years ago, the deaths attributed to cervical cancer have decreased remarkably. In spite of this, 1,500 Canadian women will receive a cervical cancer diagnosis this year alone, and close to 420 will die from it. The majority of them will either not have been screened at all, or have had an irregular cancer screening.
The biggest weakness of the Pap test is that it only detects between 50 to 80% of all precancerous lesions. The Pap test is effective only because it is performed on a yearly basis. It may take 10 years for a lesion to become cancerous, so the Pap test will eventually find it. This is also partly responsible for its downfall. Genetic tests that can detect the human papillomavirus (HPV) with great accuracy could soon play a predominant role in cervical cancer screening and…Pap tests would not have to be done annually!
The HPV genetic test currently in trial targets 13 carcinogenic strains of the virus. Unfortunately, the samples are gathered the same way as for a Pap test, so women will still have to get into stirrups. However, this test can detect over 90% of precancerous lesions, with a lot less ambiguity than the Pap test. Greater accuracy will help reduce unnecessary biopsies and lower the number of cervical cancer cases.
Although the test will not be used in clinical practice for a few years, we are quite certain women will be happy about this giant scientific step!