Cancer that arises near the tonsils or the base of the tongue, deep at the back of the mouth where the throat begins, is called oropharyngeal cancer. Yet even when the cancer sits in the same spot, the course can be quite different from one patient to the next. Some people finish treatment and go on for years without much trouble, while others walk a harder road despite being at the very same stage. One of the biggest forks in that road is whether the HPV virus was involved.
HPV is usually thought of as the virus behind cervical cancer, but it can actually settle on the lining at the back of the throat as well. Unlike the traditional form of oropharyngeal cancer, which carries the deep marks of long-term drinking and smoking, HPV-driven cancer is often found in relatively younger people, including those who have barely smoked at all. Many discover it only after going to the doctor because they felt a lump on the neck. Since you cannot tell the two apart by appearance alone, checking HPV-related markers after a biopsy is treated as an important step.
Looking purely at prognosis, when the stage is the same, HPV-positive cancer is known to respond better to treatment and to have better long-term survival. Many experts believe the cancer itself behaves differently and responds more readily to chemotherapy and radiation. For that reason, the staging criteria were even changed so that the two are scored separately. That means the same label of "T3" can sit in a different place depending on the virus status - which, from a patient's point of view, can be confusing: "My stage number is the same, so why is the explanation different?"
Still, it is a mistake to boil it down to "positive means relax, negative means despair." It is often pointed out that even in HPV-positive cancer, a long history of smoking eats away at that advantage. Conversely, there are clearly people with HPV-negative tumors who do well when the cancer is caught early and treated properly. Statistics tell you the broad trend; they do not decide the course for the one person sitting in front of you. That is why, rather than always reaching for the most aggressive treatment, there is ongoing research into ways to reduce side effects for people who are HPV-positive and have few risk factors.
In the end, what a patient needs to take care of is surprisingly simple: clearly confirm with your doctor whether your cancer is related to HPV, and how much other risk such as smoking overlaps. Even with the same diagnosis, the treatment plan and the picture of recovery can change depending on these two things. And one more thing - if you feel an unexplained lump in your neck, or one tonsil keeps feeling swollen for weeks on end, do not just brush it off; get it checked at least once.
What is written here is only general information meant to aid understanding, and the actual diagnosis and treatment should always be decided in consultation with your own medical team.