I have read that not all
HPV oropharynx cancers react positively, some behaving more aggressively like tobacco related, and believe it's type B, there is type A too, and for some unknown reason, some show an increased rate of failure after 5 years in distant areas, while tobacco related cancers level off after 2 years. These distant failure rates are not the typical areas associated with metastesses, and believe bone, and kidney were mentioned. There were articles on this, and may have been posted here previously. If I find any articles, I'll post here.
Here is one article, "Risk Varies in
HPV positive Oropharynx Cancer"
http://www.medscape.com/viewarticle/779682