If you click on the link, you'll note that the URL that comes up includes this:
/homepage.html?ie=UTF8&%2AVersion%2A=1&tag=oralcancerfou-20&link%5Fcode=hom&%2Aentries%2A=0
(boldface and color added by me).
So it's done automatically.
I have saved the page that comes up after clicking on the link (the Amazon home page, but with the "tag=oralcancerfou" in the URL) as my bookmark for Amazon. That way, when I click on my bookmark, the OCF-related page comes up.