HPV and Cancer, with Howard Bailey, MD

December 1, 2016
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In today’s podcast, Dr. Howard Bailey will discuss human papillomavirus, or HPV, and explain why it’s associated with certain types of cancer. He also discusses HPV vaccines, and how they can help lower the risk of these cancers. 



ASCO: You’re listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the world’s leading professional organization for doctors who care for people with cancer.

In today’s podcast, Dr. Howard Bailey will discuss human papillomavirus, or HPV, and explain why it’s associated with certain types of cancer. He also discusses HPV vaccines, and how they can help lower the risk of these cancers. 

Dr. Bailey is the Director of the University of Wisconsin Carbone Cancer Center, and a professor of Medicine at the UW School of Medicine and Public Health. ASCO would like to thank Dr. Bailey for discussing this topic.

Dr. Bailey: This is Dr. Howard Bailey of the University of Wisconsin Carbone Cancer Center, and on behalf of the American Society of Clinical Oncology, we're going to discuss aspects of human papillomavirus or HPV, and its relationship to cancer, and what are the various options and considerations that people should consider relative to lessening, or limiting, or stopping their risk of developing human papillomavirus or HPV associated cancers. First off, human papillomavirus or HPV is a virus that is common in that the vast, vast majority of us have been exposed to it in various ways.

It is a virus that is basically transmitted through intimate contact, most commonly related to sexual contact, and it's a virus that preferentially infects cells of the skin or of the lining of areas, whether it's the lining of our genitalia, the lining of the cervix, vagina, penis, et cetera, and also skin in other areas. These types of viruses, again, are transmitted, and then they can either provide active infections or just remain latent and not provide an infection. An active infection from the human papillomavirus means that the virus has incorporated itself into the DNA or the genetic structure of our normal cells. And how it leads to problems are that there are certain of the HPV viruses that have a very strong ability to change the way normal cells behave and in fact change those cells into cancerous cells because of the HPV infection.

HPV has many different strains or what are called genotypes—more than a 100 different types. But the main ones that we are interested in—we as patients or physicians—pertain to the viruses that are associated with either warts, whether they are common warts that you get on your hands or feet, or warts that are associated with sexual contact, which people call venereal warts. Those are not the HPV types that cause cancer, but they do cause these warts, and the most common ones that you hear about are the strains 6 and 11. But unfortunately there are multiple strains or types of the HPV virus that cause cancer. The most common types are 16 and 18, and then there are multiple others—anywhere from 5 to 8 others—that compose the vast majority of other cancer-causing HPV types. So these types, when you get exposed and have an infection, if this infection continues, they can lead to the development of cancer. And the type of cancers that are caused by HPV are predominantly cervical cancer, where all of our information both whether in the United States or worldwide implies that all cervical cancers are caused by HPV.

The next most common type, and it's increasing especially in the United States, are types of oral cancers. This is especially true in men where, as an example, in the United States the number of men with oral cancers caused by HPV will in the next 5 to 10 years exceed the number of woman developing cervical cancer from HPV. To give you an example of numbers worldwide, there's probably a half million cases every year of cervical cancer that are caused by HPV. In the United States that number is smaller—approximately 10,000 to 20,000 cases and a bit higher—and the number of oral cases, again, is starting to gradually meet that and as mentioned exceed that. But there are other cancers that are caused by HPV as well, and again it is related to the type of exposure, intimate exposure. So penile cancer are frequently caused by HPV, cancers of the vagina or vulva are caused by it, and also types of anal cancers can be caused by it. So because of this, and because unfortunately there are many men and woman who die of these cancers, there's been great interest in how we might be able to stop, or block, or prevent, or treat these HPV infections.

Over the last numerous years, there's been the development of vaccines against HPV infections. A precedent for this for, again, us as patients or providers is the fact that there are other viruses that cause cancer, and an example is hepatitis. Hepatitis B is a very common infection in parts of the world. Certainly, it occurs in the Unites States and North America, but it is very common in Asia. And in Asia because of so many people with Hepatitis B infections, there was and is a high rate of cancers caused by Hepatitis B, mainly of the liver. Many years ago—approximately 20 years ago or so—various public policies were put in place in Asia to vaccinate against Hepatitis B at a very early age. And doing that, what we're starting to see is that the numbers of people developing hepatocellular or liver cancer are starting to dramatically decline, because they're preventing these infections that cause the cancer. So with that model in mind, we've been developing across the globe HPV vaccines, and there are 3 different HPV vaccines approved in the United States and in other parts of the globe.

These HPV vaccines essentially provide protection to boys or girls, or men and women, as long as they get the vaccine before they ever develop the HPV infection. So the point I want to make is the vaccination does not treat an existing infection. But all of our data and experience says it's incredibly successful at preventing the HPV infection, and all of our data and experience says that if you prevent the infection, you will prevent the later development of cancers. The vaccine approved by the Food and Drug Association vaccinates against 9 different of the HPV strains. And the key thing to note there is, by this wider coverage, that is vaccinating against approximately 90% of all the potential causes of cervical cancer, oropharyngeal cancer, penile, et cetera.

So there, again, is a lot of desire and need on our part to continue to expand and improve upon this HPV vaccination. And again, as I mentioned earlier, the reason for this is the fact that all of our evidence and data shows that if you get this vaccination before exposure, you will not then get these infections that cause cervical cancer or oral cancer. So that's why it is recommended. It's recommended by ASCO. It's recommended by any and all of the major societies, whether it's pediatric societies or gynecologic societies, primary care, etcetera, that all boys and girls should get this vaccine. Again, the data to-date also implies and shows that it's been safe. Now that's not to say that there can't be side effects from the vaccine shot. The most common is pain or discomfort at the shot. But studies following literally multiple thousands of boys and girls, and young men and young women, there has been no evidence in these studies that those who did not get the vaccine versus boys, girls, men, and women who did get the vaccine, that there was any difference in other illnesses or diseases. So our experience strongly supports and implies that the vaccines are safe. Again, the reason we are recommending that so strongly is the fact that there are far too many men and women dying of cancers related to HPV.

The reason it's recommended, again, at a young age is two-fold. As I stated earlier, the vaccine is only effective if you receive it before you get exposure. So to be blunt, for us, whether as parents, or patients, or community members, that principally means getting the vaccine given before people are engaging in sexual activity. But the other key reason for it is that there is very strong evidence and experience that when the vaccine is given to boys and girls at a younger age, the response to it, the strength of the response, if you will, is greater than when it's given at 18, or 19, or 20 years of age. So those are the reasons why we strongly recommend to parents, or guardians, or family members, that young boys and girls receive the HPV vaccine. It provides the best response, and it's the most effective time to give it before anyone is contemplating intimate activity at that time.

In terms of testing for HPV, there is more and more done mainly for women when it comes to cervical cancer screening, where HPV testing can be done to see if you have evidence of an HPV infection that's associated with cancer development. That's something you should discuss with your physicians or providers relative to that.

Ultimately for any of us, whether it's ourselves or family, the things that we should be asking our providers related to the HPV vaccine is, again, just what we've discussed. Why is it important? What are the reasons that we should consider vaccination? And obviously, as I've described, it has to do with the prevention of cancer. Again, those of us who deal with cancer patients on a daily basis cannot stress enough the fact that preventing cancer is clearly easier and more successful than trying to treat people with advanced cervical cancer, or oral cancer, or the other cancers caused by this. So you should ask about that. You should ask about, what is the schedule for HPV vaccination?

Again, from the American Society of Clinical Oncology standpoint, we want to and need to find better ways to keep people from suffering from, and more importantly, dying from these cancer types. And clearly, our experience and the precedent with other virus-caused cancers say that the best way to do that is prevent ever having this infection that cause cancer. So with that in mind, that's why the American Society of Clinical Oncology strongly supports us implementing and getting more young boys and girls to undergo the HPV vaccine. Clearly again, questions or concerns you might have, are things you should discuss with your provider.

ASCO: Thank you, Dr. Bailey. To learn more about HPV and cancer, please visit www.cancer.net/hpv. And for more expert interviews and stories from people living with cancer, visit the Cancer.Net Blog at www.cancer.net/blog.

Cancer.Net is supported by the Conquer Cancer Foundation, which is working to create a world free from the fear of cancer by funding breakthrough research, sharing knowledge with physicians and patients worldwide, and supporting initiatives to ensure that all people have access to high-quality cancer care. Thank you for listening to this Cancer.Net Podcast.