Reading time: 4 minutes
Imagine a world in which cancer is no longer a threat to the world. Naturally, the task sounds unachievable. But much like Ethan Hunt and his Impossible Missions Force team, the Australian government has accepted this mission in the hopes of eliminating cervical cancer from the country. Now, a group of researchers has taken the bold step to provide a timeline for the campaign (Hall et al., 2018), which is free for all to read (Bonus: it won’t self-destruct).
Success is not going to be an easy task. Just the mere concept of cancer elimination from a population is rather new and for the most part, still exists only in planning and roadmap forms. Australia is the first country to make an attempt to score a victory against this menacing nemesis. Thankfully, they have a very promising plan that incorporates two complementary and evidence-based methods.
First, they are attempting to equal two other impossible elimination efforts from the past. These were aimed at two of humanity’s worst microbial enemies, smallpox and polio. Eventually, the viruses were beaten using one of our best defense weapons, vaccines.
In the same way, Australia hopes to eliminate one of the major causes of cervical cancer, human papillomavirus (HPV) infection. It is responsible for over 70% of cases of cervical cancer (World Health Organization) and has been targeted as Public Enemy #1 in this realm. Since 2007, the government has made access to the vaccine and close to three-quarters of the youth are now appropriately vaccinated. If these levels are maintained, the number of cervical cancer cases will be cut in half from about six cases for every 100,000 people today to three.
While this outcome is rather impressive on its own, it’s not elimination. Getting to that milestone requires a partner in cancer crime fighting. In this case, it’s HPV screening.
For years, the Australian government has been screening women every two years for signs of cancer using a pap test. While this has been the gold standard, its success in identifying abnormalities is known to be less than perfect (Nanda et al., 2000). Now, the administration is implementing a program in which women are tested every five years for signs of HPV infection. The accuracy of this test is better than routine screening and may improve prevention by as much as 70% (Ronco et al., 2014). With this in mind, the number of cervical cancer cases would drop significantly from three in every 100,000 to just one.
While this is an incredibly impressive rate, technically speaking, this is not the official definition of elimination from an infectious disease perspective (Dowdle, 1998). To reach that benchmark, the number would have to be zero. However, in light of the current situation in Australia, this would suffice to allow the country to say, “Mission Accomplished!”
As with every study, there are going to be limitations and certainly, this goal comes with a few concerns. The most important happens to be the rate of vaccine uptake. While the levels continue to be high, the potential for a reduction in light of anti-vaccination messages could put the mission in jeopardy. A loss in the high uptake would derail the mission and send it off the tracks.
Another issue is the realization that HPV isn’t the sole cause of cervical cancer. By going to an HPV-exclusive test, there is the potential to miss cancers that originate in the body and are not caused by the virus (Chen et al., 2013; Koliopoulos et al., 2017). These types are quite rare and may be picked up using traditional Pap smear screening as well as through an analysis of the genome and/or lifestyle behaviors.
The end result of this ambition attempt to perform the impossible will take at least a decade or more to realize meaning we’re just going to have to wait for the ending. Yet, the direction of the Australian government is promising. Much like in the days of smallpox and polio, the idea of cancer elimination has been little more than an idea without any real direction. But as cervical cancer is, for the most part, preventable, this is an excellent start to a new direction in the fight against this disease. If the Australian government can accomplish this mission, their efforts may open the door to a number of sequels in which another “impossible mission force” tackles and tries to defeat other long-time cancerous villains.
Chen, D., Juko-Pecirep, I., Hammer, J., Ivansson, E., Enroth, S., Gustavsson, I., . . . Gyllensten, U. (2013). Genome-wide association study of susceptibility loci for cervical cancer. J Natl Cancer Inst, 105(9), 624-633. doi:10.1093/jnci/djt051
Dowdle, W. R. (1998). The principles of disease elimination and eradication. Bulletin of the World Health Organization, 76 Suppl 2(Suppl 2), 22-25.
Hall, M. T., Simms, K. T., Lew, J. B., Smith, M. A., Brotherton, J. M., Saville, M., . . . Canfell, K. (2018). The projected timeframe until cervical cancer elimination in Australia: a modelling study. Lancet Public Health. doi:10.1016/s2468-2667(18)30183-x
Koliopoulos, G., Nyaga, V. N., Santesso, N., Bryant, A., Martin‐Hirsch, P. P. L., Mustafa, R. A., . . . Arbyn, M. (2017). Cytology versus HPV testing for cervical cancer screening in the general population. Cochrane Database of Systematic Reviews(8). doi:10.1002/14651858.CD008587.pub2
Nanda, K., McCrory, D. C., Myers, E. R., Bastian, L. A., Hasselblad, V., Hickey, J. D., & Matchar, D. B. (2000). Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review. Ann Intern Med, 132(10), 810-819.
Ronco, G., Dillner, J., Elfstrom, K. M., Tunesi, S., Snijders, P. J., Arbyn, M., . . . Meijer, C. J. (2014). Efficacy of HPV-based screening for prevention of invasive cervical cancer: follow-up of four European randomised controlled trials. Lancet, 383(9916), 524-532. doi:10.1016/s0140-6736(13)62218-7
World Health Organization. (n.d.). Human papillomavirus (HPV) and cervical cancer.
Retrieved from: http://www.who.int/news-room/fact-sheets/detail/human-papillomavirus
Adapted from http://www.virology.wisc.edu/virusworld/viruslist.php?virus=hpv
Leave a Reply