I’ve written somewhere north of 60 articles about the cancer preventing HPV vaccine, which I think is one of the most powerful tools in preventing some deadly cancers. Mostly, I concentrate on discussing the safety and effectiveness of the vaccine in blocking human papillomavirus (HPV) infections. Since HPV is considered the cause of a handful of serious cancers, it is a powerful cancer prevention tool. Now there’s a report that the HPV vaccine prevents skin cancer – time to see if there’s much evidence.
In a new article published in JAMA Dermatology, the authors reported that the HPV vaccine caused a significant reduction in two types of skin cancer. Before we start cheering in the streets, I better mention that data is from case studies of two, yes two, patients.
In my hierarchy of scientific evidence, case studies aren’t exactly near the top, because they really function as observations (upon which, a hypothesis can be generated). Case studies lack controls, include a very small number of subjects, and rely upon a lot of post hoc leaps of faith to show correlation and causality. However, this type of evidence will allow future researchers to form a hypothesis that the HPV vaccine prevents skin cancer, and create a series of experiments, actually clinical trials, to either support or refute that hypothesis.
Let’s take a look at the study to see what the researchers were observing.
Two adult patients, who had been previous cases of skin cancer, were given three doses of Gardasil (quadrivalent HPV vaccine). The first patient had a 62.5% reduction in squamous cell carcinomas and a 100% reduction in basal-cell carcinomas, the most common skin cancer. Moreover, patient 2 had a 66.5% reduction in squamous cell and a 100% reduction in basal-cell carcinomas. Those are pretty large reductions.
Before we slam the door on this study because it only included two patients, there’s something else that we need to consider – is it biologically plausible for an HPV vaccine to prevent two types of skin cancer? There seems to be a lot of evidence that HPV infections are related to squamous cell carcinomas, including a meta-analysis of all of the HPV and skin cancer research that concluded:
This study serves as added evidence supporting β-HPV as a risk factor for cSCC (cutaneous squamous cell carcinoma) in healthy individuals. The subgroup analysis highlights this significant association for HPV 5, 8, 17, 20, and 38, which may help to direct future prevention efforts.
As opposed to some case studies on the HPV vaccine that I’ve reviewed in the past, this one has a significant amount of biological plausibility. The physicians in this study obviously thought that they might be able to prevent, or at least decrease the rate, of certain skin cancers if the patients received the vaccine.
Based on these two patients, the authors concluded:
A reduction of SCCs and BCCs was observed in 2 patients after administration of the quadrivalent HPV vaccine. These findings highlight the possibility that cutaneous SCC development, and perhaps BCC development, may be driven in part by HPV in immunocompetent patients. Human papillomavirus vaccination may represent an efficacious, cost-effective, readily available, and well-tolerated strategy for preventing KCs.
Can we say that the HPV vaccine prevents skin cancer? The evidence is way too preliminary to make anything but a guess. Should we get the HPV vaccine based on this study? Not really.
But let’s look at this way. We already know that the HPV vaccine prevents a long list of cancers – cervical, penile, oropharyngeal, and a few others. That alone should be sufficient reason to get the vaccine. No other argument is necessary to convince most rational people to get a vaccine that can prevent a whole raft of cancers – and as we know, there aren’t a lot of choices in preventing cancer.
On the other hand, if the HPV vaccine prevents skin cancer, then that’s more or less a bonus. If it doesn’t, you’re still preventing other cancers. If it does, it’s truly going to move into the realm of a “miracle” vaccine.
If you’re on the fence about getting Gardasil for yourself or your children, then maybe, just maybe, you can look at this data and decide that potentially preventing one more cancer is well worth it.
The HPV vaccine prevents cancer. The HPV vaccine saves lives.
- Chahoud J, Semaan A, Chen Y, Cao M, Rieber AG, Rady P, Tyring SK. Association Between β-Genus Human Papillomavirus and Cutaneous Squamous Cell Carcinoma in Immunocompetent Individuals-A Meta-analysis. JAMA Dermatol. 2016 Dec 1;152(12):1354-1364. doi: 10.1001/jamadermatol.2015.4530. PubMed PMID: 26720285.
- Hampras SS, Reed RA, Bezalel S, Cameron M, Cherpelis B, Fenske N, Sondak VK, Messina J, Tommasino M, Gheit T, Rollison DE. Cutaneous Human Papillomavirus Infection and Development of Subsequent Squamous Cell Carcinoma of the Skin. J Skin Cancer. 2016;2016:1368103. PubMed PMID: 27891253; PubMed Central PMCID: PMC5116506.