HPV positive African Americans with throat cancer have better outcomes

Excerpts from an interview with Dr. Cohen

A report published in January in the Journal of the National Cancer Institute noted that the rate of HPV-related oropharyngeal cancers is rising, but there is no etiological data on what’s causing the increase. What do you think is causing the increase?

We are still trying to figure that out, but there are some things we can be confident about and some things we have to surmise. We can be confident that the number of HPV-positive and tobacco-unrelated cancer patients are definitely increasing. Also, no doubt these are sexually transmitted entities and that HPV oropharynx cancer is a sexually transmitted disease. The epidemiology strongly favors that and there likely is an immune-host component to this — the ability to eliminate the virus completely versus allowing the virus to integrate into DNA. What we do not know is why. Why are we seeing an increase in the incidence? Why do people not clear the virus? And in the subgroup of those patients, do they eventually develop cancer?

There is a parallel with oral herpes infections and the rise of HPV oropharynx cancer. There is a parallel with a change in sexual practices to more oral sexual activity versus other forms of sexual activity. And there is a parallel to a younger age of sexual activity where, because of concerns about contraception and sexually transmitted diseases, oral sexual activity may be preferred in younger individuals versus older people who are having sex to conceive.

Those may be demographic factors that are beginning to favor the emergence of HPV-positive cases. And, of course, these are things that have been going on for decades, not just now, because the virus takes 20 to 30 years to produce cancer. These are exposures that happened 20 years ago. They are trends that would parallel what we are seeing in terms of hosts that are not clearing the virus.

There may be modulating factors. We know that males are more likely to harbor the infection than females and that males have a much higher incidence — a 3-to-1 ratio — of HPV-related oropharynx cancer than females. There may be something hormone-related or differences in the immune systems that somehow protects females from developing oropharynx cancer. There may be an interaction with smoking, and some have cited an interaction with marijuana and the development of this cancer. How those may play a role in the ability of the immune system to clear this virus we still have to elucidate. But clearly there are host factors that in some individuals do not allow clearance of this virus, and we do not understand those completely.