Background
Virtually all cases of cervical cancer are caused by high-risk HPV types. In most cases, HPV is transient and spontaneously regresses without any implications. In a small percentage of the population, an HPV infection can persist for many years and can cause cell changes that may become cancerous.
HPV testing detects HPV DNA, and can determine if high-risk strains of the virus are present, identifying women at risk of having cervical cell changes often before the changes occur. Pap testing identifies changes to the cells of the cervix once they have already occurred.
Cervical cancer is almost entirely preventable if pre-cancer is detected and treated early enough.
HPV FOCAL Study
Results of the HPV FOCAL study, conducted collaboratively by BC Cancer, the BC Centre for Disease Control, and the University of British Columbia, were recently published in the Journal of the American Medical Association (JAMA)[1]. This study was the first of its kind to directly compare HPV testing to cytology (Pap testing).
The study demonstrated that HPV testing every 4 years detected cervical pre-cancer earlier than Pap testing every 2 years. At the 4 year study exit, fewer women in the HPV tested group were found to have pre-cancer than women in the Pap tested group, due to the fact that HPV testing identified women eligible for further follow-up and treatment earlier. Women who were screened for HPV were almost 60% less likely to have a pre-cancerous lesion 4 years later compared to those who had Pap testing.
Clinical implications
HPV FOCAL findings demonstrate that HPV testing can be performed less frequently, in addition to detecting cervical pre-cancer earlier. These findings could have implications for the future of cervical screening in BC. The Pap test has been the standard of care for cervical cancer screening for decades, but these study results indicate HPV testing for screening could replace the Pap test as the primary screening tool.
BC Cancer is working with the BC Ministry of Health and other stakeholders to assess the future of HPV testing in the provincial cervical screening program. HPV FOCAL provides vital information needed to inform this process.
References
- Ogilvie GS, van Niekerk D, Krajden M, et al. Effect of screening with primary cervical HPV testing vs cytology testing on high-grade cervical intraepithelial neoplasia at 48 months: The HPV FOCAL Randomized Clinical Trial. JAMA. 2018 Jul 3;320(1):43-52. doi: 10.1001/jama.2018.7464