Lee --
Welcome to OCF. You'll get a lot of support and help here.
Be sure to look through the
main part of the site, which contains tons of information -- including
this discussion of staging (the letters and numbers) and grading (well differentiated, moderately well differentiated, etc.).
The chart on page 6 of
the .pdf file referenced on the staging/grading page goes into greater detail and will tell you what that (a) means. (In your case, it's oropharynx. The letter has to do with the extent the cancer has moved into surrounding areas.)
Keep coming back, and encourage your wife and other family members to sign on as well -- there is information here that will help them, too.
All the best,
Leslie