I've been playing D&D with the same people -- same GM, same world, same characters -- since 1981. I was a latecomer to the game, which started in 1978. I believe it's the longest-running D&D game with the original players in the world.
To me, that is really impressive, but I confess that this is a world I know very little about, so I'm turning my question over to the experts - is he right? To summarize:
What is the longest running game of D&D with the same original players, characters, and GM?
Keeping with the quote, it does not have to be the same campaign, although I'm not sure you can rule that out from his comment - there are no further details given.
Someone asked in a comment about the "regularity" I would consider valid. For these time spans (35+ years), I would be happy with at least one session per year, but I'm not sure there has to be a strict rule about that.